KR970007257B1 - Packet transmission system and method utilizing both data bus and dedicated control lines - Google Patents

Abstract

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Description

How to utilize both packet transmission system, data bus and dedicated control line

1 illustrates a wireless packet communication system suitable for realizing the present invention.

FIG. 2 is a block diagram of a packet device, suitable for use with the system shown in FIG.

3A and 3B illustrate certain packet formats utilized by a communication controller and peripherals to communicate with other devices.

4 is a flow chart illustrating data transfer from a communication controller to a peripheral device as shown in FIG.

5 is a timing diagram illustrating a control signal utilized in accordance with the flowchart of FIG.

6 is a flow chart illustrating data transfer from a peripheral device to a communication controller as shown in FIG.

FIG. 7 is a timing diagram illustrating the control utilized to transmit information according to the steps of FIG.

Background of the Invention

The present invention relates to a packet transmission system and is particularly suitable for packet systems that must accommodate a variety of other peripherals.

In a packet network, the digital information is divided into packets each containing a packet header, digitalized data corresponding to the transmitted information, and error checking information, so that the receiving node of the system verifies that the packet was received correctly. You can do it.

These packets are sent from the node to node to the destination addresses contained in the packet. In the destination address device, the packet is disassembled and information is provided to the receiving device.

Packet protocols become increasingly inefficient by reducing the amount of data to be transmitted per packet due to the required packet overhead required for each packet. Although short commands may be sent using packets from one point to another, the receiving device may need to disassemble the packet and request time for packet transmission before the command can be sent to the destination device. There is a real delay before it can operate according to the command.

In a conventional direct control system, each function to be controlled is assigned to a separate wire or communication channel, which passes certain commands from the controller to the device executing the function. Such systems have many applications and are effective where a limited number of commands are sent to a particular device. Such systems become increasingly complicated by the increasing number of devices and commands to be controlled. Addressing is not required since each dedicated path in these systems has a single predetermined function for control.

There is a need for a system and method of delivering information that utilizes packets while minimizing the inefficiencies associated with sending commands to related devices.

Summary of the Invention

One embodiment according to the present invention includes a device connected to a network interface bus comprising a packet bus and a control line capable of transmitting packets to a communication controller. The apparatus may be required to transmit upon receiving a command from the controller. The apparatus determines whether the network interface bus can accept data by determining whether the first and second control lines have a predetermined binary state. If a network interface bus is available, the device causes the first control line to change to another binary state. The data is then written onto the packet bus for communication with the controller.

The apparatus causes a third control line acting as a packet clock to change the binary state, thereby providing a signal to the controller for reading the recorded data. If additional data is transmitted from the device, it is written to the third control line and bus toggled to be read by the controller. The device indicates the end of the packet by causing the first control line to change from another state to a predetermined state.

Detailed description of suitable embodiments

1 illustrates a wireless packet communication system in which the control module 10 is configured to communicate with one or more user devices 14, each of which constitutes a terminal, personal computer, telephone or other information input / output device. Use communication. In the system, the control module 10 is also connected to the data network by the data channel 16. The control module controls the communication in the network shown, sending information from the data network via channel 16 to the user device 14 via the associated user module. The control module also controls local communication by receiving information from one user module and relaying the information to another user module. Wireless information is delivered in the form of packets. The data network to which the control module 10 is connected may be configured as an Ethernet network.

2 is a block diagram illustrating an embodiment of a packet system according to the present invention. This embodiment is for a user module of the system as shown in FIG. The communication controller 17 includes a microprocessor 18 coupled with a read only memory 20, a random access memory 22, and a network interface 24. The network interface consists of appropriate registers and line drivers to communicate with peripheral devices connected to the network interface (NI) bus 26. The peripheral structure of the NI bus is described below.

In the structure as shown in FIG. 2, a two-way RF radio device 28, a T1 gateway input / output device 30, an ISDN gateway input / output device 32, and a telephone input / output device 34 are provided. It consists. Each peripheral 28-34 includes NI bus interfaces 36, 38, 40, and 42, respectively. These interfaces provide the registers and line drivers needed to communicate with NI bus 26, and will also include MPUs, RAMs, and ROMs if these resources are not available to peripherals. The wireless device 28 includes one or more antennas 44 for RF communication with the control module 10 as shown in FIG. T1 gateway I / O device 30 is connected to the T1 line by wire 46. Likewise, ISDN gateway I / O device 32 is connected to the ISDN network by wire 48. Telephone I / O device 32 is connected to telephone equipment by wire 50. The peripheral described above merely indicates that virtually any type of information can be connected to the NI bus by a suitable input / output device. Various peripheral devices reformat the communicated information in the appropriate format over the NI bus for communication to other devices connected by paths 44-50.

3A illustrates a suitable embodiment of a packet format utilized for communication from controller 17 to peripheral devices on NI bus 26. In general, the inclusion of NI headers and NI information is fragmented. The NI address field contains the address of the receiver peripheral device. The NI length field contains the number of bytes in the NI command field. The command field is used to control a peripheral device, for example for a peripheral device such as a poll for the status of an interface, a poll for data received by the interface, or a poll for transmit / receive data. Contains a command. The information field may or may not exist depending on which command was sent. For example, a poll-for-status commmand may not have an information field because it can return a well-defined status byte (or bytes) each time a peripheral device is polled. In contrast, the poll command for a state may be limited to information requiring specific state information from the state information set maintained by the peripheral device. An example is a peripheral that controls several interface ports, such as multiple telephone lines, in which case the controller can poll for the status of a particular line, and an information field is used to convey which line is designated. . The information field also contains a well-formed data packet containing a header, data and CRC field for transmission. By way of example, the command field may include a radio transmit command addressed to wireless device 28, in which case the NI information field contains the data to be transmitted.

Figure 3b illustrates a suitable embodiment of the NI bus packet format for controller and controller communication. Since all traffic of certain embodiments is routed through the controller, the NI address field contains the address of the controller. However, direct peripheral and peripheral communication is possible, where the address field contains the address of the destination peripheral, the NI data field contains the data requested by the controller, and an additional byte field from the peripheral. Contains state information. The additional byte field is optional. In contrast to this format with that of FIG. 3a, the NI address constitutes the NI header and NI data with or without additional byte fields, and the NI information fields.

The methods described in conventional software operating systems that provide various operating capabilities depending on the particular operating environment will most advantageously be integrated.

4 is a flowchart illustrating the steps performed by communication controller 17 to send data or commands to a peripheral device connected to the NI bus. The timing diagram described in FIG. 5 also relates to the transmission of data packets from the communication controller to the peripheral device and can be understood in relation to the steps described in FIG. The timing diagram of FIG. 5 shows a physical NI bus consisting of a packet bus, packet control, packet departure, NI source, and a separate control line for the bus clock and a packet bus with multiple lines to carry one byte of data during each bus clock cycle. Indicates. NI source and bus clock lines are always controlled by the communication controller, and the remaining lines and packet buses are bidirectional. That is, the communication controller and the peripheral device may write to or read from these lines.

Data communication from the communication controller to the peripheral device is performed as follows. Beginning at start 52, the controller drives the NI source line from high to low as shown in step 54. This provides controller control of the NI bus and communicates with all peripheral devices that will receive data to be sent from the controller. In step 56, the controller drives the packet start line from high to low indicating the start of packet transmission to be sent by the controller to the peripheral device. The controller then writes one byte of data onto the packet bus as shown in step 58. In step 60, the controller drives the packet clock line from high to low and back high. The peripheral device reads the data written to the packet bus during the high low of the packet clock. In decision step 62, the controller determines whether all data has been sent. If not, returning to step 58, the next byte of data is written onto the packet bus and the cycle is repeated. Upon completing the writing of all data (YES in step 62), the controller drives the NI source line from low to high, which releases control of the NI bus in step 64, and from low to high indicating the end of the packet. Drive packet departure. This method is completed at end 66.

In the embodiment as shown in Figures 4 and 5, the communication controller sends a single packet as described in Figure 3a to one or a predetermined group of peripherals. The NI header contains an NI address, that is, a peripheral address of a specific peripheral device or a group address for a preset peripheral group. After receiving and decoding the peripheral address included in the NI header, each peripheral can determine whether the following information is specified. If the information is assigned to a peripheral device, it continues reading of the data sent by the controller. If a packet has not been assigned to a peripheral device, the information no longer needs to be processed, only a high transition is retrieved from the row of the packet start line indicating the end of transmission of the packet. Although the embodiment shows the simultaneous transition of NI source and packet start in step 64, the controller alternatively indicates the end of packet transmission by keeping the NI source line low and driving the packet start line from low to high. By driving the packet start from the next high to the low, it is possible to start the transmission of another packet, thus transmitting from high to low transition, which is a signal sent to the receiving device where data is stable and readable between subsequent packet transmissions. Controlled by the upper teeth.

6 is a flowchart illustrating the steps performed by a peripheral device in transmitting data to a communication controller. These steps are described with respect to the timing diagram shown in FIG. The timing diagram of FIG. 7 illustrates packet termination, which is an additional control line not shown in FIG. In the previous example with respect to FIG. 5, the packet bus, packet clock and packet start line were sourced by the communication controller. With respect to FIG. 7, the packet bus, packet clock and packet start line are sourced by the peripheral device. Packet termination, NI source, and bus clock are sourced by the controller.

In the departure step 68, the flag F is set to zero. This flag is usually related to the controller's ability to allow any additional bytes or data to be sent after the end of the packet, indicated by the start of the packet. The operation of this flag is described in detail below. In step 69, a determination is made by the peripheral device as to whether a command from the controller is directed on the packet bus to transfer data. The determination of NO in step 69 causes return to departure step 68, which allows the peripheral device to transmit data except where indicated by a previous command sent on the packet bus by the controller. Because there is not. The controller normally polls each peripheral device to determine its status and to determine if data should be sent to the device. With the example determination of step 69, the method ends at step 74 in accordance with the example determination by step 70. The method terminates at termination 72 since the example decision by step 70 requires the NI source to be high to allow transmission by the peripheral device at step 74. The yes decision at step 74 indicates that the NI bus is utilized for data transfer by the peripheral device.

In step 78, the peripheral device drives the packet start line from high to low, thus notifying the controller to receive data. The peripheral device then proceeds to write data to the packet bus in step 80. The peripheral device then drives a high to low packet clock line that provides a timing signal to the controller to read data on the packet bus. In step 84, a determination is made whether the packet termination is low. The packet termination line is controlled by the controller and can be utilized to complete transmission by the peripheral at any time. Proceed to step 84. A yes determination causes the peripheral device to initiate a stop delivery data sequence 88 at which data transfer is stopped. The no determination by step 86, i.e., if the flag is not set, then there is a determination of the peripheral device whether all data has been sent in step 90. The no decision is returned to step 80 where additional data is sent to the controller. An example determination by step 90 indicating the end of a given data transfer by a peripheral device causes the peripheral device to drive a packet start from low to high as shown in step 92. This tells the controller that the peripheral has finished sending packets. The method is completed at step 94 following step 92.

The following description shows the controller's ability to prematurely terminate data transfer by the peripheral device. This sequence is started by the controller driving the packet end line low, which is an example decision by step 84. In step 96, the peripheral device responds to this command by setting the flag to one. In step 98, a determination is made by the peripheral device as to whether more data remains to be sent to the controller. The determination of NO returns to steps 92 and 94 to complete the transfer. An example determination at step 98 indicating that there is more data to be transmitted returns to step 80 where the next byte of data is written to the packet bus and the packet clock is incremented at step 82. If the packet end line remains low as determined by step 84, the peripheral proceeds with the same sequence of steps until all data has been sent as determined by step 98. However, if the controller causes the flag F to be reset by driving packet termination from low to high, then a no decision is made at step 84. In this case, since the flag is set, step 86 makes a yes decision, and accordingly executes the stop function immediately in step 88. In this way, the controller can complete the transfer of data by the peripheral by driving packet termination from high to low back.

In the embodiment as shown in FIG. 7, the packet start line is driven by the peripheral device from low to high before the end of packet complete line complete command, ie from high to low again. As such, this example illustrates that a peripheral completes its transmission of data without interruption of the controller. The bold dash line associated with the packet start line of FIG. 7 shows an alternative example, in which the peripheral device was retained with data to be transmitted but was interrupted by a packet end command, thus the packet start line was bold. It remains low until it starts and returns high with a packet end line driven low to high by the controller. This mechanism has the advantage that additional data bytes can be sent beyond the preselected packet as determined by the packet start line. As such, it is possible for the peripheral device to immediately send a number of additional bytes of information following a packet. Such bytes of information may be utilized to monitor the status of the peripheral, or may correspond to normal update information provided to the peripheral following the transmission of the packet. This allows such information to be communicated without having to be conveyed in the packet. This provides additional flexibility in communication, which is particularly beneficial when each of the multiple peripherals communicates with a common controller.

If a peripheral transmits information in one packet that will be sent to another peripheral connected to the NI bus, the controller processes the packet to reformat the packet with the NI header addressed to the destination peripheral and NI. Will transmit on the bus. As such, the communication controller not only provides a common point of communication coordination, but also acts as a traffic cop of information and packet routing between peripherals.

It will be apparent to those skilled in the art that the method of the present invention may be implemented in hardware as well as in state as well as in software.

Although embodiments of the invention have been described and illustrated as described above. The scope of the invention is defined by the following claims.

Claims (8)

A device connected to a network interface (NI) bus having a packet bus and a control line, the method for transmitting data to a communication controller connected to an NI bus, comprising: (a) a first control line and a second control line Determining whether an NI bus can accept data from the device by determining whether it has a preset binary state; (b) if the NI bus can accept data, the device changes the first control line to another binary state; (c) recording the data bytes to be transmitted on the packet bus; (d) providing a communication controller with a signal that reads the recorded data as the third control line acting as a packet clock changes the binary state; (e) if additional data is to be transferred, repeating steps (c) and (d), and (f) terminating the data transfer as the first control line is changed from the other state to a preset state. And transmitting the data to a communication controller connected to the NI bus. The method of claim 1, further comprising: monitoring a binary state of a fourth control line under control of a communication controller, and wherein the monitoring step transitions the fourth control line from one state to another and from the original one state Terminating the transmission of additional data upon sensing; transmitting data to a communication controller connected to the NI bus. 3. The method of claim 2, wherein the completing step allows additional data to be transferred until the fourth control line changes from the other state back to one state. An apparatus connected to a network interface (NI) bus having a packet bus and a control line capable of transmitting data to a communication controller connected to a network interface (NI), the apparatus comprising: a binary binary in which a first control line and a second control line are preset; Means for determining whether an NI bus can accept data from the device by determining if it has a state; Means for changing the first control line to another binary state if the NI bus can accept data; Means for recording data to be transmitted on the packet bus, the third control line acting as a packet clock changing the binary state, thereby providing a communication controller with a signal for reading the recorded data; Means for determining whether additional data is to be transmitted and for causing each of the recording means and the providing means by the third control line to provide a communication controller with a signal for writing additional data on the packet bus and reading the additional data; And means for indicating the end of the data transfer by changing the first control line from the other state to a preset state. 5. The method of claim 4, further comprising monitoring a binary state of a fourth control line under control of a communication controller, wherein the monitoring means detects a transition of the fourth control line from one state to another and from the original one state. And means for terminating the transmission of additional data when the device is connected to the NI bus. 6. The apparatus of claim 5, wherein the terminating means is adapted to transmit additional data until the fourth control line is changed from the other state to the original one state. In a communication controller connected to a network interface (NI) bus having a packet bus and a control line, a method for transmitting a data packet to a device connected to the NI bus, comprising: (a) the first control line is in a first binary state; Gaining control of the NI bus by changing to another binary state at; (b) indicating the start of the data packet by causing the second control line to change from the first binary state to another binary state; (c) recording a data packet information byte to be transmitted on the packet bus; (d) changing the third control line serving as a packet clock to a binary state, thereby providing a signal for reading the recorded data packet information byte to the apparatus; (e) repeating step (c) and step (d) when additional data packet information including data packets is transmitted; And (f) indicating the end of the packet by changing the second control line from the other state to the first state, and releasing control of the NI bus by changing the first control line from the other state to the first state. And transmitting the data packet to a device connected to the NI bus. A communication controller connected to an NI bus having a packet bus and a control line capable of transmitting data packets to a device connected to a network interface (NI) bus, the communication controller comprising: a binary in which the first control line is different from the first binary state Means for obtaining control of the NI bus by changing to a state; Means for indicating the beginning of a data packet by changing the second control line from the first binary state to another binary state, means for recording a data packet information byte to be transmitted on the packet bus; Means for providing the apparatus with a signal for reading recorded data by changing a third control line serving as a packet clock to a binary state; A signal for determining whether additional data packet information including data packets is to be transmitted, causing each of the recording means and the third control line changing means to transmit additional data on a packet bus, and to read the additional data; Means for providing; Means for indicating an end of a data packet by changing a second control line from the other state to a first state, and means for releasing control of the NI bus by changing the first control line from the other state to the first state; A communication controller connected to the NI bus.