Signal transmission direction switching device for USB, includes arbitration circuit connected so that incoming signal edge is connected to bus-coupler in sending state

The Invention relates to devices for switching the direction of the signal transmission for USB (Universal Serial Bus).

As is known, is the USB (Universal Serial Bus) is a four-wire connection, wherein serve a twisted pair of signal transmission and the two other compounds a power cable and the cable mass are. The Signal transmission simultaneously in synchronous or asynchronous mode, wherein up to 127 current devices may be connected to a computer.

In of the <patcit><text>DE 100 83 913 T1</text></patcit> (Higher Rates are supportive USB transceiver) are the transceiver designed so that these signals are sent at a higher than the standard USB specification can be and receive. It can the transceiver configure itself. This solution refers to the high-speed transmission or high-speed communications in computer or computer systems. The publication<patcit><text>US 6363085 B1</text></patcit> (Universal serial bus repeater) is a means for switching the direction the signal transmission for the known USB bus by a transmitting bus coupler is detected and a second bus coupler is switched to receive. It is between terminals of two interconnected buscouplers a circuit for Arbitration present, which is connected such that the first edge an incoming signal to a bus coupler to the other bus coupler into the "Send" on and that this bus coupler until the detection of SE0 on receiving other Bus coupler remains in this state. The two bus coupler are connected via lines for signal transmission connected with each other.

Of the in claim 1 specified invention, the object is an object, a direction switching signal transmission with a USB with minimum effort and utmost protocol independence to ensure.

These Problem is solved with the features listed in the patent claim. 1

The Means for switching the direction of the signal transmission for the USB (Universal Serial Bus) are distinguished in particular by the possibility its simple circuitry realization of. this will advantageously by switching to a lower protocol layer reached.

Of the USB is known to be a simple four-wire connection. The signal transmission via a twisted pair D + and D-. The other two compounds represent a power cable and the cable mass. The USB is a high Data rate and an effective protocol organization ensured. About the single twisted pair, the data in synchronous or asynchronous transmit mode. The USB also allows the use of up to 127 simultaneously current devices for one Computer.

On Switching to a low protocol layer is achieved by that between the terminals both "Send a "and Bussensor of two over the lines for transmitting signals to each other connected bus coupler circuitry for arbitrating switched so is that the first edge of an incoming signal on one of the bus coupler the other bus coupler into the "Send" on and that this bus coupler signifying that SE0 on receiving other bus coupler in this State remains, said switching signal transmission independent of Signals or functions of higher Protocol layers at least one connected to one bus coupler unit is. The signal transmission then takes this into the "Send" connected bus coupler from other Bus coupler, which has remained in the "receiving".

In the arbitration phase is thus determined which device next his information about USB transfers. These monitors the circuit for arbitration via the bus coupler both ends of the USB. In the ground state are both directions the signal transmission switched to "receive". A Request to send a device is used to switch a bus coupler to the state "Send" recognized until SE0 becomes. In this SE0 bus coupler is switched back to the state "receive". Only Thereafter, the same or another device switches over the transmission request again one of the bus coupler in the state "Send", the other in the "receiving" remains.

On Such an approach is possible since the bus only Host-controlled works (master-slave principle), that means it always sends only one bus, and a slave sends only Upon request; It thus sends either the host (= root of Hierarchy tree) or from the host to summoned bus users.

The Delay Time the signal transmission is be greater than the switching time of the circuit for Arbritation to state "Send", so that a complete signal transmission is secured. The at&lt;?page 3?&gt;required bus coupler is characterized before signal transmission switched to the state "Send" so that a complete signal transmission takes place on the other bus couplers.

The Circuit for arbitrating are state-controlled switch, respectively the outputs the bus coupler each one-state-controlled switch to the control terminal the respective other bus coupler is interconnected. such ensures realization the switching of the bus coupler in a low layer protocol and simultaneously provides a very simple and uncomplicated Building represents.

furthermore are advantageously the ports VP (transmission signal) and VM (Transmission signal negated), the bus coupler to the inputs respectively an evaluation circuit and the outputs of the evaluation circuits interconnected with each of the input state of the controlled switch.

A advantageous embodiment of the invention in claim 2 indicated.

Cheap configurations are to the embodiment of claim 2 for the state-controlled Switch flip-flops and for the evaluation circuits exclusive OR gate.

On embodiment the invention is illustrated in the drawings and will be described in more detail below.

It show:

<figref idrefs="S7">1</figref> a basic illustration of a means for switching the direction the signal transmission for the USB (Universal Serial Bus) and

<figref idrefs="S8">2</figref> a Means for switching the direction of the signal transmission for the USB (Universal Serial Bus).

A Means for switching the direction of the signal transmission for the USB (Universal Serial Bus) consisting of a circuit for arbitrating <figref>3</figref>. between the terminals both "Send on" <figref>4</figref>. <figref>6</figref> as also Bussensor <figref>5</figref>. <figref>7</figref> of two lines for signal transmission <figref>8a</figref>. <figref>8b</figref> together connected bus coupler <figref>1</figref>. <figref>2</figref> switched is (representation in the <figref idrefs="S7">1</figref>). It guarantees the circuit for arbitrating <figref>3</figref>That the first edge the transmission request one of the two bus coupler <figref>1</figref>. <figref>2</figref> in the state "Send" on and that this bus coupler <figref>1</figref>. <figref>2</figref> signifying that SE0 remains in this state, wherein the switching to the signal transmission independently of signals or functions of at least one of the second bus coupler <figref>2</figref>. <figref>1</figref> switched appliance is. The circuit for arbitrating<figref>3</figref> must ensure this, the delay time the signal transmission greater than the switching time of the circuit for arbitrating to the state "Send on ".

The Circuit for arbitrating <figref>3</figref> consists essentially of two flip-flops <figref>9</figref>. <figref>11</figref> as state-controlled switches and two exclusive-OR gates <figref>10</figref>. <figref>12</figref> as evaluation circuits. The connections VP and VM of the first bus coupler <figref>1</figref> are connected to inputs of the first exclusive-OR gate <figref>10</figref>Whose output is connected the input of the first flip-flop <figref>9</figref> and whose output is connected to the control terminal of the second bus coupler <figref>2</figref> connected together. The connections VP and VM of the second bus coupler <figref>2</figref> are connected to inputs of the second exclusive OR gate <figref>12</figref>Whose output is connected to the Input of the second flip-flop <figref>11</figref> and whose output is to the control terminal of the first bus coupler <figref>1</figref> connected together. The <figref idrefs="S8">2</figref> shows such an implementation of a device for switching the direction of the signal transmission for the USB (Universal Serial Bus).

there is ensured, that the state SE0 the bus coupler <figref>1</figref>. <figref>2</figref> each "Receiving" are connected in the state, that upon detection of the first LH edge of a bus coupler <figref>1</figref>. <figref>2</figref> of the other bus couplers <figref>2</figref>. <figref>1</figref> signifying that SE0 into the "Send" ge is off and that the state SE0 on a HL edge of the bus coupler <figref>1</figref>. <figref>2</figref> in the State "receiving" is switched.