Portable data processor which selectively activates and deactivates internal modular units and application processor to conserve power

BACKGROUND OF THE INVENTION

This invention relates generally to portable data collection and data processing apparatus, and more particularly to microprocessor operated circuits for controlling the operation of such apparatus.

Portable, hand-held electronic data processing units have taken on an increasingly significant role in business control systems. Battery powered, hand-held data collection terminal units are used for inventory control in warehousing and merchandising operations. Other uses of such terminal units include invoicing, delivery route and order taking operations, and fast check-out and return control in automobile rental operations.

Portable terminal units may typically include radio communications modules which maintain a real time communication link with a host computer and hence with a comprehensive business system.

Certain limitations affecting the use of these terminal units relate to communication route loading, namely to the limited number of terminal units which may conveniently become linked to a host over the same communication channel, or at best over a limited number of channels. Multiplexing and time slot access protocols typically establish upper limits for the number of data terminal units in any one system. To accommodate a larger number of terminals within any one system radio access becomes a premium. Data manipulation and compression prior

0 to transmission and on-board data storage may be

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- 2 implemented to increase data transmission rates and reduce access requirements. Typically, increased data processing capabilities are also accompanied by comparative increases in power consumption. In a hand-held, portable data collection and processing terminal an increased power consumption is, however, undesirable because of a resulting shorter operating cycle between battery recharge operations. Power saving improvements for such hand-held units are therefore highly desirable and are the subject of development effort.

Many diverse uses of hand-held terminal units or apparatus in present day business systems would ideally require a great number of distinct models of the terminals, each having a specific configuration tailored to one of the many particular uses. When changes in the hardware configurations of data collection terminals are implemented to meet specific needs, the manufacturing costs of the respective terminals tend to increase unreasonably. It has been attempted to reduce manufacturing costs due to model changes by providing functional modules which may selectively be used in distinct combinations to make up various models of a data collection and processing terminal apparatus.

However, interconnecting modules in a number of different combinations tends to increase problems of communication among the selected modules. A particular problem relates to a decrease in product reliability when a great number of specialized data connections are needed. Simplification and further improvements are desirable to electrically couple in a simple manner any of a great number of combinations of functional modules for different models of portable data collection and processing terminal units.

Typically, the hand-held terminal units are controlled by microprocessor devices which operate

PCT/US93/05648 ~ 3 under the control of stored programs. Such devices are ideally suited for controlling various data processing operations. In general, microprocessor controlled operations of data terminal units involve data Input-Output (I/O) functions including displaying information on a screen, transmitting data messages by radio, receiving data inputs from data scanners or bar code readers and responding to keyboard inputs. Microprocessors also perform internal control functions such as monitoring power. Data processing operations or manipulations involve sorting, storing and retrieving both text and numerical data, as well as updating and controlling information in data bases. Popular data terminals also make use of various prompts and menus which may appear in a number of stacked levels. The speed of presenting updated menu information, requested data or other written instructions is considered a significant element in rating the performance of a data terminal unit. Although it is desirable to provide more powerful microprocessor functions to increase user friendliness by faster processing speeds, a resulting increase in power requirements for such more powerful microprocessors negates the feasibility of such improvements.

It is known in the art to use two or more microprocessor devices for more complex control operations. The processors typically operate in parallel, speeding up operations while maintaining comparatively lower clock speeds. Complex operations are thus completed at any given clocking rate in a relatively shorter time than with a single processor. A power increase due to an added microprocessor is offset by the greater computing power implemented without the need to drive a single microprocessor at a higher speed or to use a single microprocessor of a more complex architecture. However, portable data terminal units which require

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- 4 extended operating time before having their power units recharged typically would not employ such multiple microprocessor enhancement.

To improve the usefulness of state-of-the-art 5 portable, hand-held data collection terminal units, it would be desirable to implement further power saving circuit structures and operations and to provide interconnections among modules which are simple and reliable. Such improvements are seen as minimizing the cost of providing specialized configurations of data collection terminals, providing greater versatility and greater user friendliness.

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- 5 SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a power efficient control circuit for a portable data collection terminal or data terminal unit.

A further object of the invention is to provide a reliable communication method and apparatus among various functional sub-units of the data collection terminal unit.

It is a particular object of the invention to provide for high speed serial communication among various functional sub-units of the data collection terminal unit.

Another object of the invention is to provide a control circuit which minimizes idle clocking cycles of power intensive microprocessor control and data processing elements.

A further object is to speed up response time to input, output and data display demands on a data terminal unit without a typical resultant increase in power consumption of such terminal unit.

In describing the invention, terms are given their typical meanings, the following definitions of which are believed to fall within these most commonly understood meanings. A microprocessor device is a control device capable of executing a sequence of logic instructions at a speed of operation determined by the frequency of clocking signals applied to the microprocessor. A memory or storage device may be a RAM (Random Access Memory), either volatile or nonvolatile, a ROM (Read Only Memory) , or any of a number of available electrically programmable and erasable and otherwise permanent storage devices. Data are one or more numerical quantities or constants of predetermined value, representing individually or in combination intelligence or information. Data may be transferred over digital signal lines as binary signals, or as

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- 6 radio frequency signals by RF transceiver units, or the data may be stored in storage cells, either temporarily or permanently, in typical storage devices or memories. A program is a sequence of logic instructions which, when applied to a microprocessor, control the operations of the microprocessor. An application program typically denotes a specific program consisting of a series of logic instructions which control the operations of a microprocessor in its manipulation, operation on, and routing of data by the microprocessor, as well as the generation of predetermined control signals or signal sequences at certain defined points in any operational cycle. The control signals may be applied according to selected program instructions to concrol, among other things, the terminal intelligence or operational sequences of the data terminal unit.

According to the invention, data communication and processing apparatus comprises a plurality of functional sub-units or modules. Selected ones of such modules include a communication and control device. A high speed data communication bus links the communication and control devices in each of the modules.

According to a more particular aspect of the invention the data communication and processing apparatus includes a base terminal unit which includes a first microprocessor element or device which is particularly dedicated to processing data. A selective activation of the data processing device or application device is controlled by the communication and control device of the base unit. The application element becomes deactivated during idle periods and its activation is initiated by the communication and control device upon receipt of a control signal indicative of the occurrence of an

PCT/US93/05648 event which requires data processing operations on data as a result of the event.

A more general aspect of the invention includes at least one communication and control processor device and a separate intermittently operable data processing element which is controlled by at least one communication and control processors.

Accordingly, a specific aspect of the invention includes an apparatus, including a microprocessor control circuit for use in data processing apparatus which includes a first microprocessor device which is dedicated to data processing operations. A second microprocessor device controls data input and output sequences of the data terminal unit and controls a selective application of processed data to or from the first microprocessor device to or from data output or input devices of the apparatus. The microprocessor control circuit is characterized in that the second microprocessor also controls the duty cycle of the first microprocessor device and in that the first microprocessor is operational for substantially less than fifty percent of an averaged period of operation of the control circuit.

According to a particular combination the first microprocessor device may be a relatively more power intensive element, such as a 16 bit microprocessor and the second microprocessor device may be operational with relatively less power, such as an 8 bit microprocessor. The first and second microprocessor devices may be advantageously coupled to communicate through a parallel communications interface for transferring data between the two devices in response to interactive trigger or According to a particular combination, the first microprocessor device operates at least at twice the speed of the second microprocessor device and the second microprocessor device disables the first handshake signals, feature of such

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- 8 microprocessor device after it has completed any particular operation and has communicated its completion to the second microprocessor device.

Particular power saving features and advantages 5 of such combination of the first and second microprocessor devices reside in the relatively less powerful device controlling and selectively turning on and off the more powerful first device which operates at a substantially higher clocking rate than the controlling second device. One of the advantages of the resulting intermittent operation of the first device is a power reduction with respect to a microprocessor control circuit having a continuously operational single device for providing a similar rate of screen updates, menu displays and data base manipulations.

Other features and advantages will become apparent from the following detailed description, ’which may be read in reference to the drawings.

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- 9 BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic pictorial representation of a modular data collection terminal unit to which the present invention applies and showing schematically physical representation of modules of the data collection terminal.

FIG. 2 is a schematic diagram of functional interfaces among various modules of the data collection terminal shown in FIG. 1.

FIG. 3 is a schematic diagram of a control microprocessor, illustrating data bus terminals for synchronous communications.

FIG. 4 is a sequencing diagram showing schematically occurrences of a module-initiated communication sequence in accordance with features of the invention.

FIG. 5 is a further sequencing diagram illustrating schematically occurrences of a controller-initiated communication in accordance with features of the invention.

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- 10 DETAILED DESCRIPTION OF THE INVENTION Functional interconnections and power saving features of the present invention may be better understood from knowing how various building blocks or modules of a portable data collection terminal unit relate to each other. FIG. 1 shows a schematic arrangement of various physical modules or components that become integrated into the portable data terminal unit which is designated generally by the numeral 10. Hand-held terminals are of generally rectangular, elongate shape for accepted practical user friendliness, thus the modular terminal unit 10 desirably has an elongate, rectangular shape. An upper module 12 provides a sensory or physical interface to an operator of the terminal unit 10. The module 12 is referred to as a keyboard and display module 12 and features a keyboard 14 which may be a typical alphanumerical keyboard 14, including also function keys and cursor manipulation keys as part of an integrated keyboard arrangement. The keyboard 14 may be, and desirably is, a submodule 14 in itself, inserted and mounted into a mounting frame 15 of the keyboard and display module 12. In a typical manner, the depression of molded keytops 16 generally closes electrical contacts in a lower contact plane (not visible) of the keyboard 14. The type of keyboard 14 is, however, not critical and not considered limiting to the invention. The keyboard being a selected one of a number of available keyboards 14 is, however pertinent to the invention. For example, in one application the keyboard may be preferred to be a twenty or a twenty-four key keyboard 14. Such a keyboard 14 comprises comparatively few keytops 16 the locations and functions of which are more readily learned and accepted by an operator. Such keyboards typically do not have alphabetical key functions. Thus for many record keeping and

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- 11 merchandising operations, the keyboard 14 having an array of twenty or twenty-four keytops may be most desirable. In another operation, a greater number of keytops 16 may be required to display the letters of the alphabet, numbers, and to provide keytops 16 for the execution of various functions. Thus, a keyboard 14 having an array of fifty-six keytops 16 may be preferred for example. Numerous variations in the arrangement of the keytops 16 within the array of the keyboard 14 are additionally possible. Mechanical or touch sensitive keytops 16 may be employed. In fact, touch sensitive, keyboards which are known in the art, and which typically involve programming and bi-directional feedback, may be improved by interconnection features of the present invention which will become apparent from the detailed description as a whole.

The keyboard and display module 12 further includes an upper cavity 17 wherein a display screen 18 is disposed. The display screen 18 is preferably a state-of-the-art liquid crystal display, the liquid crystal display (LCD) technology being well established in the art. User friendliness and versatility of the display ideally calls for a dot-addressable liquid crystal array screen 18 which permits the display of various alphanumeric characters and also permits the display of graphic symbols as well as display of Chinese or Japanese character symbols. Of course, dot-addressable graphic iepresentations are known to require a substantial level of data processing and memory storage to permit the symbols to be displayed or moved about on the display screen 18 with reasonable speed. Long delays between the time that an operator pushes a keytop 16 to obtain data and the time that the requested data are displayed is considered user unfriendly and is commercially undesirable. A display technology which has become

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- 12 a standard is referred to as VGA technology. VGA screens are capable of fine gray scale or color resolutions. The display screen 18 would be part of a selected display screen module 19 of a number of available display screen modules. FIG. 2 refers to a display screen module 20 which is similar in function, yet which may included selected differences to illustrate the advantages of the modular concept in combination with other features of the present invention. Display screens may vary in size or resolution or both, such that options among a number of display screen modules 19 may be mads available to a potential user of the terminal unit 10. A display of an array of (128 by 240) pixels of, for example, (0.25 X 0.25) millimeter is an example of what is considered to be a desirable display screen resolution. Another screen array size may be (64 X 192) pixels, for example, of (0.35 X 0.50) millimeter per pixel.

The keyboard and display module 12 occupies most of the area of the terminal unit 10 which faces an operator when the terminal unit 10 is held and operationally used by the operator. Assembled to an underside 21 of the keyboard and display module 12 are preferably two major modules of the terminal unit 10. A first module is what is referred to as the terminal module 22. Whereas the keyboard and display module 12 is the major interface component between the operator and the terminal unit 10, the terminal module 22 is a major functional component of the terminal unit 10 itself, as will become apparent from the description herein. The terminal module 22 functionally controls the interaction of the various unir? sc modules as described herein, and functionally is the control unit 22 of the terminal unit 10 as a whole. The terminal module 22 houses functional submodules and microprocessor circuits. A significant, and also space consuming

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- 13 component is, of course, a power pack module 23. The power pack module may contain, for example six AA type rechargeable cells which may be arranged in a convenient flat arrangement and fitted into a battery end 24 of a housing 25 of the terminal module 22. The power pack module 23 supplies the power to various modules of the terminal unit 10, thus providing the capability for portable use of the terminal unit 10.

From the above description of potential choices of the type of display on the display screen 18, and further choices among keyboard arrangements of the keyboard 14, different requirements for electronic support circuits are indicated. One of the requirements in the support of changing functions economically is a means to provide a ready change in programmability of microprocessor circuits. Some module selections of the terminal unit 10 require less memory usage and different operational protocols than others. In accordance with a preferred embodiment, a memory module 27 may be selected as one of a number of differently programmed memory modules 27. However, in addition to being differently programmed, an alternate memory module 28, as shown in the functional diagram of FIG. 2, may include a different memory size (in cell numbers and in configuration). The terminal module 22 may further include an exchangeable memory card 30. The memory card 3 0 may be used to provide additional memory capacity as well as control programs for various desired functions of the various modules as described herein. The memory card 30 is schematically shown as being insertible laterally into a slot 32 of the housing 25 of the terminal module 22. However, the shown physical arrangement is but one of a number of equally desirable arrangements. Environmental protection of modules of the terminal unit 10 may desirably

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- 14 suggest an enclosed and sealed arrangement for the memory card 30.

A peripheral I/O module 34 is shown in one of the two longitudinally opposite ends and is disclosed as being located at a lower or inner end 3 5 of the termi al unit 10. The inner end 3 5 is typically pointed toward an operator of the terminal unit 10, as the unit is held in the operator's hand with the keyboard and display module 12 directed upward toward the operator. The I/O (Input-Output) module 34 may typically include externally of a housing 36 a standard RS-232 and RS-485 connector 37. FIG. 1 also depicts a round communication connector 38. The peripheral I/O module 34 provides an interface betwet?.n the terminal unit 10 and such diverse peripheral devices as docks which are batch transfer devices for accumulated data and battery charging devices, and cables which may connect to a code scanner, for example. The RS-232 interface may typically also become connected to a printer, for example. All these peripheral devices (not shown) are well known and are not part of the invention.

At a longitudinally opposite outer end 40 of rhe terminal unit 10, a serial I/O and scan connection module 41 may be attached. The scan connection module 41 is a high speed serial data communication module 41 which provides for serial data to be received in high volume from a scanner for example. Scanner data are typically received in a high density data string and require significant processing. As will become apparent from the further detailed description, a direct communication link to the data processing capability of the terminal unit 10 is provided through the scan connection module 41.

A further functional module of some significance is a communication module 44. Again in

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- 15 reference to FIG. 1, the communication module 4 4 may be disposed adjacent the terminal module 22 toward the outer end 4 0 of the terminal unit 10. The communication module 44 is selected from a group of available communication modules of distinct functions. The selection of one of the communication modules such as the communication module 44 in FIG. 1, may characterize or classify the operation of the terminal unit 10. For example, a communication module 44 may have been selected from a group modules which include standard FM data radio transceiver modules, spread spectrum radio transceiver modules, modem communication modules, scanner device modules, or other data input devices. FIG. 2 shows a communication module 45 as an alternate to the physical representation of the communication module 44 shown in FIG. 1 to indicate a diversity of modules available for substitution. In further reference to FIG. 1, the communication module 44 is shown as having an antenna 46, indicating the selection being a transceiver unit for radio frequency real time communication with a data system. Such a data system includes typically a further transceiver station, not shown, with which the transceiver module 44 communicates. The second transceiver station as a receiving end of a link is not shown as it is commonly understood that communication is the transfer, the transmission or reception, of information or data over a communication link established between two points. The operator of the terminal unit 10 also constitutes a second end of a communication link that is established by the operator's manipulation of the keyboard 14 and by the operator's visual perception and recognition of the data displayed on the display screen 18. Thus, ^.he term communication is understood as linking the modules to other units. The presence or absence of the

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- 16 other units is of little significance to the teachings of the present invention. These external units are therefore not shown to better emphasize the features of the invention.

Referring now to FIG. 2, there is shown a functional schematic diagram of a combination of the physical modules discussed with respect to FIG. 1 or of alternate equivalents of the modules in FIG. 1. The modules with respect to which preferred physical positioning was discussed in reference tc FIG. 1 are now shown functionally related in FIG. 2. The terminal module 22 clearly appears as a central functional device. It is to be noted that the schematic representation refers to functional or communication rather than electrical connections. The power pack 23 is typically coupled to power all electrically driven circuits of the terminal unit 10. The power pack 23 is functionally and physically coupled to the terminal module 22. While electrical power is distributed from the power pack 23 to all electrically powered or controlled modules of the terminal unit, the remaining power of the power pack is actually monitored by a function of the terminal module 22. The power pack 23 as the sole portable power source for the terminal unit 10 would, but for power saving provisions, experience a significant power drain during the operation of the terminal unit 10.

Power savings are implemented in a manner which typically implies a greater usage of power but which enables power savings by more selectively using circuit functions as they are needed. Accordingly, the terminal module includes preferably first and second microprocessors 48 and 49, respectively. The first microprocessor 48 is a data processing device and is also referred to herein as an application processor 48. The application processor may be any of a number of available microprocessors available.

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- 17 Desirably the application microprocessor 48 has the capability of processing data with greater word length or word width than the second processor 49. The term word width refers to the number of data bits that are capable of simultaneously being processed, retrieved or stored. The application processor 48 is therefore one capable, for example, of processing a 16-bit or a 32-bit data word. The processing speed and clocking rate would desirably exceed those of the second microprocessor 49. At present, the more powerful microprocessor, such as the microprocessor 48, also has a higher power requirement than the second microprocessor 49. However, even with the high power requirement during operation, power savings may be achieved by providing a rest state at which the microprocessor 48 is, for example, not clocked and thus deactivated.

The second microprocessor 49 is also referred to as a control processor 49. The second microprocessor controls the operation of the terminal module 22 and controls communication within the terminal module as well as among the various other modules of the terminal unit 10. Desirably, the control processor 49 does not have the operational power requirement as the application processor 48 for reasons that will become apparent. Control is an ongoing function. Although the operational speed of the control processor 49 is comparatively slow with respect to that of the application processor 48, the operational power consumption of the control processor 49 is also desirably lower than that of the application processor 48.

A presently preferred device for the control processor is of the characteristics that are presently found in a Hitachi H8/330 type microprocessor device. The Hitachi H8/330 processor

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- 18 features on-board memory which is convenient for its intended operation as will be seen in reference to its operational modes as set forth herein. The H8 type processor is an 8-bit processor, capable of processing data in an 8-bit word length. However, the control processor need not be an 8-bit processor. In general, the word width processing capacity of the control processor 49 would be chosen to be relatively less than that of the application processor 48. The control processor 49 does not require the processing speed that is desirable for the application processor 48, and, according to the state of the art, processors with relatively low word width processing capacity (considering processors in general) require less processing power. It is to be understood, however, that the specification of any particular device, such as was done with the Hitachi H8-type microprocessor for the control processor 49, is for illustrative purposes only. Continual development efforts in microprocessor architecture is expected to result in various commercially available devices that may be of equal or better utility than the specified exemplary devices. The features and desired functions of the invention will be helpful to one skilled in the art to select any of a number of acceptable devices to function in the desired manner as described herein.

FIG. 3 shows a schematic block representative of signal terminals of the control microprocessor 49 which are pertinent to the preferred mode of implementing the present invention. In describing the significant signal and data terminals, a bar above a designation indicates a signal low being the active state of the signal. In the specification hereof the inverse or signal low active state is described with an N preceding the letter name at the respective signal term.

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- 19 10 final product of reliability may be interconnection faults, with each advantages dissipated.

To communicate among the various described modules, four signal leads of the control processor 4 9 define the leads of a communication bus 50 referred to herein as MBUS. The MBUS 50 is a high speed synchronous serial data signal bus which may, and preferably does, operate at a signal rate of 500 kilo bits per second. Better reliability of data transfer is achieved by using the high speed data bus. In a modular structure in which the modules are readily uncoupled and reconnected to permit convenient changes during the manufacture of the the terminal unit 10, the noticeably affected by When reliability decreases additionally coupled module, the of modular structure are quickly In contrast to typical parallel data buses used to link components of electronic products or systems, the present system architecture of the modular terminal unit 10 significantly reduces the number of contacts needed to interconnect the various modules.

Reliability might be further decreased by electrical noise and interference coupled into the interconnected signal lines. With fewer signal lines to manage, it becomes feasible to protect each line from noise and interference effects by using well known shielding, impedance reduction and termination techniques. Thus, the system of the present invention provides greater reliability than modular systems with conventional parallel data transfer.

FIG. 3 shows a four signal terminal which constitutes the MBUS concept. i-ICLK is the which synchronizes the modular the control processor 49. The clocking signal provides for a bit rate of 500 kilo bits per second. The terminal labeled MTXD clocking signal counterparts of

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- 20 transfers data from the control processor onto the MBUS 50. The terminal labeled MRXD receives data from other modules over the MBUS 50. The low signal active NMATT is a control signal line which indicates that data will be communicated over the MBUS 50. These four lines effectively permit the various modules to communicate among each other,

A number of signal contention protocols are available and are commonly known for resolving potential collisions in data communication. Any of the various contention protocols will suffice to resolve priority conflicts when data are to be transferred among the various modules. It is to be understood that any standard conflict resolution procedure also may be modified if so desired to assign specific priorities for communication among the modules. For example, data received from a scanning operation may be accepted and processed on a priority basis. Keystroke inputs from the keyboard and display module 12 may be given priority over data flow from the communication module 45. Similarly data messages received via radio transmission from an external master unit (not shown) may be given priority. Program altering instructions may be embedded within a data message. The embedded instructions may affect future operations that are about to be received from one of the modules.

Further with respect to FIG. 3, corresponding data lines interfacing with the application processor 48 are indicated as parallel signal lines DBO-7 and data lines AO-3. Data communication and control procedures between the control microprocessor 49 and the application processor 48 are further described with respect to alternate embodiments.

The application processor 48 is coupled to an asynchronous device or UAR/T function 51 with an

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- 21 output coupled to a serial port 52 of the serial I/O scan connection module 41. The serial I/O scan connection module 41 further includes a scan port 53 which links to the control processor 49 and enables it to communicate control signals, such as, for example, scan trigger signals. The application processor 48 is further coupled to a VGA adapter circuit or driver 54 for driving the display screen 20. The display screen function is processor intensive. Data processing operations are, therefore, managed directly through the application processor 48. The data processing operations performed by the application processor 48 are in most instances memory-usage intensive. Consequently, the application processor 48 is linked by a conventional data bus 55 directly to the memory module 28. The memory module 28 is shown as including representative data storage functions or circuits including a 16-bit word width system FLASH-programmable memory 56, a typical 16-bit word width random access memory 57 (RAM), and additional application FLASH-programmable memory 58, also preferably 16-bit word width. The 16-bit word width storage devices or functions 56, 57 and 58 are preferred in conjunction with a 16-bit microprocessor device representing the application processor 48. Presently preferred devices may be for example a Chips and Technologies F8680 device or an Advanced Micro Devices 386SXLV processor. It must be understood, however, that other devices may exist or may become available that are equally acceptable or even better suited to function as the application processor 48. In addition, selecting a different microprocessor 48 may result in a different selection of memory device types, word widths, or storage capacitites.

The peripheral I/O module 34 may, as discussed with respect to FIG. 1, include standard connectors

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- 22 for coupling the module 34 to an external device. A particular device 59 may be a portab.le printer device, as shown in the function block 59 of FIG. 2, which may be mounted or coupled directly to the terminal unit 10. The peripheral I/O device, whether it is a printer, a reader, or other data input or output device, would functionally include a microprocessor 60. The microprocessor 60 is chosen to interact with the MBUS system and i$ coupled in each described element to function as a terminal element, i.e.. an interface communicatively coupling the respective logic circuits of the module to the MBUS. Thus, when the respective microprocessor receives a communication over the MBUS 50, a recognition of control codes may cause the microprocessor 60 to transfer data or execute a control instruction, which may entail activating or de-activating the power circuits of the respective module or conditioning the module to receive or transmit data.

The communication module 45, which, for example, may be a modem or any of a number of available radio frequency transceiver modules, also includes a compatible microprocessor 60 which interfaces with a respective communication device 61 of the module 45. The communication device 61 would, corresponding to the desired function of the module, be a modem or transceiver device, for example. To be compatible with the MBUS data format of the other described modules, the keyboard and display module also preferably includes a distinct interfacing microprocessor device (50. The keyboard and display microprocessor 60 is coupled to control various elements which are directly associated with the keyboard and display module 12. A particular function that may be conveniently controlled via the MBUS 50 and the respective control processors 49 and 60 is a backlight drive 62 function for the display

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- 23 screen 20. Another function incorporates a buzzer 63. The buzzer 63 may be programmed to signal an audible alarm as a response to an incorrect key depression by an operator. The buzzer 63 may further be used to alert an operator when a charge and power control circuit 64 detects that the power pack 23 has become discharged and a backup battery 65 is being engaged. In addition, the power control 64 may function to shut down the terminal unit 10 from further operation until the power pack has been recharged or replaced. In the preferred mode, power from the back-up battery 65 would nevertheless be maintained on the control processor to enable it to determine when the power pack 2 3 has in fact been recharged or replaced.

The processor 60 of the keyboard and display module 12 may also control other input or output devices that may be coupled to the keyboard and display module 12. For example, a pen 66 may be coupled to the keyboard and display module 12 for use in connection with a pen stylus sensitive keyboard module 14, or in connection with a pen stylus sensitive display screen 20. In this latter instance, the display screen module 20 becomes an input device in addition to being an output device. The input is received through manipulation of the pen 66 by an operator.

The application processor 48 and the control processor 49 are preferably controlled through a timing Application Specific Integrated Circuit 67 (clock control ASIC). The clock control circuit 67 may be driven from a single clock signal which is then divided to provide respectively different clocking rates to each of the processors 48 and 49. The implementation of the timing circuit 67 in a single circuit function is more efficient and provides synchronization among the components and

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- 24 modules. A second clock signal for implementing a real time clock may be provided.

In addition to the reliability advantages of coupling modules via the four-line MBUS mentioned above, the MBUS 50 also provides a space saving advantage, i.e.. more compact physical routing of cables among the modules.

Power savings which are obtained through the control of the functions of the various described modules via the MBUS 50 will be best understood from the following description in reference to FIGS. 4 and 5. To conserve power and prolong the operational time of the terminal unit 10 between recharges or replacement of the power pack 23, the control processor 49 and the related MBUS module processors 60 perform a special power-saving control function: any module which is not in active use is placed into a dormant state.

The MBUS 50 communicatively interconnects the modules of the terminal unit 10, such as the peripheral I/O module 34, the communication module 45, the keyboard and display module 12 and the terminal module 22. Other modules which in the future may be included in the active communication network of the MBUS 50 may simply be added as described herein. For each module, one of the microprocessors 60, having the data terminals of the microprocessor 49 shown in FIG. 3 (i.e.. terminals MCLK, MTXD, MRXD and NMATT) is coupled to the respective lines of the MBUS 50 to become part of the internal communication network of the terminal unit 10. The microprocessors 49 and 60 constitute the terminal elements of the communication network represented by the MBUS 50. For each module, the respective microprocessor 60, though it may be physically identical to the control microprocessor 49, functions as a subservient processor to the control processor 49. The microprocessors 60

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- 25 become a communication interface between the MBUS 50 and the functional circuits of the respective module, whether it is the communication module 45, the keyboard and display module 12 or the peripheral I/O module 34. Inputs from the respective module are accepted by the processor 60. An H8/330 microprocessor includes internal memory for receiving and temporarily storing data communications. Programmable ROM on the H8/330 permit instructions to be stored which particularly configure the microprocessor as a module processor 60. The interface operation of the microprocessor 60 differs from the controlling operation of the control processor 49 as may be realized from the description of the interaction of the processors in reference to FIGS. 4 and 5.

A normal state of the microprocessors 49 and 60 is a sub-active or dormant state. In this state, the module processors 60 and the control processor 49 are clocked at a power saving slow clocking speed. The sub-active or dormant operational state permits the module processors 60 and the control processor 49 to execute certain long-interval control functions, such as watching for a keytop depression by the keyboard and display screen processor 60 or a low battery signal to be received by the control processor 49 from the charge and power control circuit 64. Upon occurrence of an event which affects the operation of any typical communication function which is driven over the MBUS 50, all modules and the control processor are placed into a fully activated mode. The control processor 49 queries, directs and controls communication over the MBUS 50.

For example, FIG. 4 shows an activation cycle of the MBUS 50 which is initiated by one of the described modules other than the terminal module 22, i.e.. from ctne of the processors 60. The respective

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- 26 ~ processor 60 drives the NMATT line of the MBUS 50 into a low signal state. The low state of the NMATT line activates all processors 60 to receive an inquiry or instructions. At T1 in FIG. 4, all modules have been placed into the active state. During the time interval Ti to T2 the control processor sends a query or polls the activated modules over the MTXD line, which is reserved for transmissions originating from the terminal module

22, i.e., from the control processor 49. The query would typically contain at least one byte of data. The quantitative translation of the byte of data indicating to the processors 60 that it is a query in response to one of the module processors 60 having driven the NMATT line to a low state. The query shown at 71 signals the processor 60 to transmit its data message over the MRXD line of the MBUS 50. At the onset of the data transmission 72 from the respective communicating module processor

60, the NMATT line is restored to a high state, placing all other modules back into the dormant condition. As shown in FIG. 4, the data communication may proceed for a variable length-of time past the time state T2 at which the NMATT line has returned to a high state. Upon termination of data communication from the respective module processor 60 to the control processor 49 the control processor 49 sends a message 73 confirming correct receipt of the data message (at T3) . Again the confirming data message contains at least one byte of information, the decoding of which would either indicate an error code or signal the correct receipt of the data message. At that time (at T3), the communicating module processor 60 and the control processor 49 also assume the power saving dormant state.

FIG. 5 describes a very similar event in which the control processor 49 drives the NMATT line to a

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- 27 low state. Again, all processors 60 assume an active state and receive a communication 75 of typically at least one byte of information from the ccmtrol processor 49 during the time interval between Ti and T2. The information 75 contains an address of the module to which a data message from the control processor 49 will be directed. The respective module processor acknowledges its understanding of the address by a responding message 76 which may be translated by the control processor 49. In response to the receipt of the message, the control processor releases the NMATT line which assumes its normal high state and places all non-affected module processors 60 again into a dormant state. The control processor 49 then transmits its data message as indicated at 77 to the respective previously addressed module processor ¢0. At the conclusion of the communication 77 from the control processor 49, the respective module processor acknowledges receipt of the communication 77 by its response 78. On transmission and interpretation of the response 78 that the communication 7” has been received correctly, both the control processor 49 and the respective module processor 60 assume their dormant states. It is to be noted that the respective data messages shown in FIGS. 4 and 5 indicate durations of data messages. It is to be understood that the high and low states of other than the NMATT line indicate a time interval during which a great number of high or low states in synchronous time slots are transmitted essentially at the bit rate of 500 kilo bits per second. This bit rate may include start and stop intervals.

In the described communication events, power consumption by the terminal unit 10 is minimized by providing for a quasi dormant state for substantially all functions of the various modules, such that electrical power is used in pulses during

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- 28 the described query states and only in spurts by certain modules during real time performances. Highly power intensive data processing operations in the terminal module 22 provide further power savings in communication from and to the various modules.

The term data processing operation is used herein to describe the manipulation of a series of binary codes according to programmed instructions to arrive at a desired result. Because of the great number of discrete binary operations required to perform many of the most common data processing functions, higher processor speeds and more complex or powerful microprocessor circuits of those typically available are more desirable for data processing operations,,

The application processor or data processing device 48 may be an ^rflntel 80C188EB device which is 16-Bit microprocessor device, operated at a preferred speed of 9.2 megahertz (MHz). At such preferred clocking speed of 9.2 MHz, the power consumption or operating current consumed by the data processing microprocessor device 48 is approximately 55 milliamps (mA). The control processor 49 is in the particular implementation a Hitachi H8/325 device which is an 8-Bit microprocessor, operated at a speed of one-half of the speed of the data processing microprocessor 48, or 4.6 MHz. Because of the smaller physical size of the control processor 49 and the slower, preferred clocking speed, the power consumption or current required by the control processor 4 9 in its operational mode is only about 9 mA, hence less than one-fifth of the power consumed by the processor 48. Because of continuous advances in the field of microprocessors over the past decade, it is to be expected that in the future other microprocessors will be marketed which will meet or exceed the requirements of the presently preferred

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- 29 microprocessors and that these microprocessors also may operate in accordance herewith. In general, the control microprocessor circuit or the control microprocessor 49 desirably operates at a slower and less power consuming speed than the application microprocessor circuit or the application microprocessor 48. A one-to-two speed ratio for driving the respective microprocessors 49 and 48 is preferably chosen because of the power savings that are realized with respect to the portable terminal unit 10.

The clock control circuit 67 may be expanded in its function to include an interface circuit between the processors 48 and 49, which incorporates data transfer as well as clocking functions. The clock control circuit 67 would include in such coupling arrangement a typical divide-by-two timing circuit function. An original 9.2 MHz clocking signal port and a signal port with the divided by two signal would be coupled to the respective timing signal input ports of the processors 4 8 and 49, respectively, to drive the processors 48 and 49 at their respective speeds of 9.2 and 4.6 MHz. As already described, a second clock may be coupled to the clock control circuit 67 to provide a real time clock.

The preferred control processor 49 includes in its commercial implementation, in addition to typical microprocessor registers and an arithmetic logic unit, such functional circuit blocks as ROM, RAM and communications ports. According to a preferred embodiment, data communication between the processors 48 and 49 occurs via an interface circuit including, for example, two 8-bit data registers or latches (not shown) . It is to be understood, however, that the control processor 4 9 may have a direct bus interface provision and become directly coupled to the application processor 45, the coupled

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- 30 processors 48 and 49 thereby being capable of bidirectionally passing data and control signals without two 8-bit data registers or latches. Also, data latches are generally considered temporary data storage devices. Data from one device are latched into a respective data latch to be retrieved by a second device. Therefore, in general, the operation of the data latches constitutes a primitive equivalent of what is known as a dual port memory. Dual port memories or memories which are accessed via at least two ports are known in the art. The substitution of the below described latches with a dual port memory in a data storing interface is therefore considered to be within the scope of the present invention. The clock control ASIC function 67 shown in FIG. 2 should be understood to not only include the clocking signal coupling circuits to drive the respective application processor 48 and the control processor 49, but to further include the data interface or bus to permit the desired bidirectional data and control code communication between the processors 48 and 4 9 as further described herein. In further reference to FIG. 2, an integration of the processor devices 48 and 49 into a single device desirably may include the referred to function of the interface and clock control circuit 67 as an integral part of an integrated circuit (not shown).

Tests have shown that typical data processing operations performed by the application processor 48 require approximately 10 milliseconds of time, and not more than 20 milliseconds, on the average. It has further been found that a more user friendly and a more practical response time may be obtained from the terminal unit 10 with less power required when substantially all data processing operations are performed by the application processor 48 and the application processor is subsequently immediately

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- 31 deactivated, than if a single alternative microprocessor circuit were used operating at a higher rate and including sufficient computing capacity to perform all required functions in cn appropriately short time. In the preferre/₍ selection of the two processors, the combination of the application processor 48 and the control processor 49 amounts only to an approximate increase in current usage of typically about ten percent, and in the extreme, of no more than 20 percent over the normal operating current level of the control processor by itself. The combined power consumption of the application processor 48, as controlled by the control processor 49, and the control processor

49 is about one fifth of the power consumption of the application processor 48 itself when it is operated continuously. However, the display speed and data manipulation speed of the terminal unit 10 essentially is the same as if the terminal unit 10 were controlled by the more powerful application processor 48.

The operating current requirement for the application processor 48 is directly related to the number of actively switching elements in each computational operation. Though having an interrupt function, the referred to 80C188EB processor 48 does not include, in contrast to the control processor 49, any internal memory devices. FIG, 2 consequently shows a data bus 55 of the processor 48 coupled to external memory devices, such as the system FLASH memory 56 (functionally equivalent to a read-only memory or ROM), the flash electrically erasable and programmable read-only memory 58 (FLASH EPROM) and a typical random access memory

57 (RAM). The data bus 55 further couples the application processor directly to the display module 20 (LCD DISPLAY) of the terminal unit 10, such as a dot addressable LCD graphic screen module, for

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- 32 example. A direct data transfer by the high speed application processor 48 to the LCD screen is preferred because of substantial amounts of data handling or processing that is required in updating a particular screen. For example, even a small graphic screen display, such as a screen of 48X100 pixels, requires that each of the pixels be updated on a continuous basis. Typically, control circuits, which are part of the data display function of the module 2 0 and are not separately shown, and which may be specific to a particular screen display, may routinely re-apply currently displayed information dots in a cyclic refresh operation to the already identified pixels of the screen. However, to update the screen, each pixel of the screen must be updated. This is so for any updating of the screen, even for a simple display line scrolling operation which an operator may not even consider noticeable or significant. To facilitate such updating of information in a prompt, user-friendly, and power efficient manner, a data processing operation and the high speed passing of the updated data between the RAM memory 57 and the data display 20 is performed during a short operational activation of the application processor 48. More data processing with respect to the data display screen 20 may be required for routine menu operations. Menu operations are particularly desirable for such portable terminal units 10 because the typical user may not be well acquainted with computer terminals. Well defined menu operations with a number of available menu levels are found to significantly increase the user friendliness of a terminal unit. An efficient menu operation is known to involve data base searching and data retrieval in addition to the normal display screen updating operation. The described microprocessor circuit with the selectively activated data processing device 48 and

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- 33 the relatively smaller and slower control processor 49 has been found to be particularly advantageous for these purposes.

A selective activation and deactivation of the microprocessor circuit portion implemented by the data processing device or application processor 48 would also provide power savings when the operating speeds of the two processors 48 and 49 are the same. If both processors 48 and 49 are being operated at the same speed, however, the power savings is not as great as that realized in accordance with the preferred embodiment of the described invention.

FIG. 2 shows schematically an arrangement of electrical components of an exemplary terminal unit

10, and of the preferred interactive relationship of such components with the application processor 48 or the control processor 49. In the embodiment shown in FIG 2, the application processor 48 controls directly the RS-232/485 standards serial interface

34. The flash EPROM programmable read-only memory is preferred to have no less than 256K byte storage capacity. The flash EPROM may supplement or even replace standard ROM, such as memory 56 which is preferred to have at least a 512K byte storage capacity. In the preferred example of the terminal unit 10, the ROM, if used, would provide typical and normally non-variable data processing protocol instructions. Such ROM may include control instructions for standard display updating routines as well as for other routines which are typically implemented by standard keyboard instructions and which pertain to typical data input and output commands.

The random access memory 56 is in the specific emboaiment a semi-permanent static RAM type circuit. The memory may have a capacity of 512K bytes. The preferred data storage capacity has been determined to provide sufficient storage for an on-board data

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- 34 base related to typical inventory or delivery route type information. In view of the portability of the terminal unit 10, an unexpected loss of battery power may bring about a significant loss of information unless the data stored at the time of a temporary loss of battery power are protected from destruction until full battery power is restored. For example, the terminal unit 10 may be returned at an initial signal of low battery to a battery charger unit (not shown) for a recharging operation and any stored data may be transferred, even while the battery 23 is being recharged, from the terminal unit 10 to a host computer (not 16 shown in FIG. 1).

A preferred LCD display 20 is a graphic display having an array of 48 x 100 pixels. Typical menu or special graphic screen data may be pre-established for a particular terminal unit 10 or for an application group of such units and may be stored initially in the specific ROM 56 provided for the particular unit or units 10. As previously discussed, the updating of displayed data on the screen device 20 requires a significant amount of data processing. Typically, such data processing operations involve accessing permanently stored screen display information, such as from the ROM 56 or from the flash EPROM 58, the manipulation of such information, and temporary storage of such manipulated information in the random acces' memory 57. As shown in FIG. 2, the application p ocessor 48 has direct functional control over the respective devices for such data updating manipulations with respect to the LCD Display screen 20.

Another function that is desirable in connection with LCD display screen 20 is contrast control. In regards to FIG. 2, such a control may be integrally coupled to the VGA adapter circuit 54 . The contrast of the LCD display screen 20 is typically set and adjusted by an operator and is a

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- 35 matter of choice. The contrast may be adjusted for example by a typical key depression or by a keyboard sequence given by an operator. Such control input executions are within the scope of operations of the control processor 49. The contrast display may be controlled as indicated in FIG. 2 by the functional coupling of the keyboard circuit 12 to the control processor 4 9 and the further coupling of the processor 48 to the contrast control circuit and then directly to the LCD display screen circuit 20.

The LCD display screen 20 in the preferred embodiment is equipped with the back lighting drive 62. Many warehouse operations, route delivery operations and even merchandising inventory operations must often be performed under sufficiently poor lighting conditions, thereby requiring a backlighting source to be supplied as a standard feature of the LCD display screen 20. A preferred backlight drive circuit 62 is preferably coupled through the MBUS 50 to the control processor 49. A preferred backlight drive circuit for use in conjunction with the exemplary terminal unit 10 is described in applicant's co-pending PCT patent application Serial No. PCT/US9208646 filed October 12, 1992. Because an operator may wish to adjust the backlighting (i.e.. for example, its brightness or luminescence), both the application processor 48 and the control processor 49 may interact with the backlight drive circuit 62 to provide for an operator controlled brightness control sequence to be communicated to the backlight drive 62.

Besides the timing function circuits for the real time clock and its functions, the control circuit 67, as an ASIC, may also include the clocking signals to each of the two processors 48 and 49. The control circuit 67 may also provide the data communication functions between the application processor 4 8 and the control processor 4 9 by two

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- 36 latching circuits as mentioned above. Also as mentioned above, the control processor 49 functions to activate or wake up the application processor 48 for data processing operations. In one contemplated embodiment the control circuit 67 may include integrally a switching circuit function for separately switching the application processor 48 off or on. Such a switching operation may be implemented by a typical switch as part of the integrated control circuit 67 which selectively interrupts and reestablishes the clocking signal to the application processor 48. The function of deactivating and reactivating the application processor is controlled in a preferred embodiment via the control device 67 in a somewhat different manner. Instead of controlling the clocking circuit to the application processor 48 in the control circuit 67 with a control signal from the control processor 49, the control function is preferably split. In other words, the application processor 48 provides a shutdown status signal to the control processor 49 and then shuts itself down. The control processor 49 subsequently returns the application processor 48 to an active state upon the occurrence of any event which requires the operation of the application processor 48.

Further in reference to FIG. 2, a trigger control signal of the scanner module 41 may be received by the control processor 49. However the data flow from the scanner modulo 41 would be received directly by the application processor 48 for further processing and storage. Input signals which are received at speeds within the operational capability of the control processor 49 are received by and transferred through the control processor 49. For example, key depression signals from the keyboard 49 are preferably received directly by the control processor 49. A preferred keyboard size for

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- 37 the terminal unit 10 referenced herein, as indicated in FIG. 2, is a 6x8 key matrix. Such a size is optimal because of space considerations and requires that multiple functions be implemented by each of the keys. However, the selection of a preferred keyboard remains in any case one of choice and has no particular bearing on the teachings of the invention.

Because of the slow realtime key function selection by an operator in comparison to the fast processing speed of even the slower control processor, the interpretation of which key function has been selected may be made by the control processor 49, An event indication character communicated to the application processor 48 preferably reflects already which of the available functions of a particular key has been selected. The preprocessing of relatively slow occurring events has been found to limit the operational periods of the application processor 48.

The control processor further controls an input to an audible alarm circuit 63 (BUZZER). An audible alarm is a slow occurring event which alerts an operator of an alarm condition or signals that a processing operation has been completed. For example, when the application processor 48 has received a string of data from a bar code via the scanner module 41, and has further processed the received information to verify its correctness, the application processor 48 may communicate an acceptance code to the control processor 49 and be shut down from further operation. The control processor will then routinely generate an audible signal to alert the operator of the acceptance of the information. Prior to communicating the acceptance code to the control processor, the application processor may retrieve from its memory 57, for example, further information relating to the

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- 38 bar code information which has just been read and accepted, and may compile an information screen displaying such retrieved further information to the operator prior to the deactivation of the application processor 48. Thus, by the time the operator is alerted by the audible signal that the respective bar code information has been read and accepted, the pertinent further information relating to the bar code information is already displayed on the LCD display screen 20.

Another device which is preferably under direct control of the control processor 49 is the power control circuit 64 (CHARGE/POWER CONTROL) of the terminal unit 10. A serial interface 34 may optionally be controlled by the control processor 49. Based on the power saving interaction between the application processor 48 and the control processor 49, various additions of other devices or functions to the general operation of the terminal unit 10 may be feasible without unduly limiting the operational cycle of the terminal unit 10.

The interaction between the control processor 49 and the application processor 48 is described in greater detail in reference to FIG. 2. In general, the application processor is restricted to data processing operations. The operations of the control processor 49 generally pertain to input-output control functions which include periodic monitoring functions, such as monitoring the state of the battery 23 via the charge/power control circuit 64. Though less powerful and slower than the application processor 48, the control processor 49 controls the activation or reactivation of the application processor 48. However, the application processor 48 preferably processes the parameters and feeds the respective instructions by which the control processor is operated to the control processor 49.

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- 39 Changes may be made in the selection of the first and second microprocessor devices 48 and 49 as application and control processors, respectively. The described microprocessor devices have been found particularly suitable for various operations that were expected to be performed by the terminal unit 10 in the above-referred to operations.

It should be realized that, depending on the contemplated type of portable use, various other changes and modifications in the structure of the described embodiment would be possible without departing from the spirit and scope of the invention as set forth in the claims.

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- 40 IN