JPH01256840A - Communication equipment coupling terminal equipment and network - Google Patents

Abstract

PURPOSE:To attain high speed processing by using an external designation switch only so as to determine a protocol and applying DMA data transfer with a network. CONSTITUTION:Communication equipments 20a, 20b exist across a high speed network 21 and the communication equipments 20a, 20b act like relaying the communication between terminal equipments 23a, 23b. The communication equipment 20a consists of a network interface control section 30, an internal bus 31, a DMA circuit 32, a protocol control circuit 33, a DMA interface circuit 34, a protocol designation switch 35, a data buffer 36, a reception circuit 37, a transmission circuit 38, and an internal bus 39. One protocol is designated by the designation switch 35 and data transmission and reception is applied between the communication and the terminal equipment according to the designated protocol. Moreover, the transmission and reception data is stored tentatively in the buffer 36 in the communication equipment and the data is transmitted between the buffer 36 and the network 21 by a DMA circuit 32 in terms of DMA transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication device installed between a terminal device and a network, and particularly to a communication device configured without a microcomputer.

[Conventional technology]

A conventional example is JP-A-62-98791. In this conventional example, one semiconductor device is provided with a plurality of functions, and any one of these functions can be selected.

A shift register was provided as selection means for this purpose.

[Problem to be solved by the invention]

In the above conventional example, there is no description regarding microcontroller-less DMA transfer. Furthermore, there is no description of application to communication devices.

[Means to solve the problem]

The present invention provides a dedicated protocol control circuit that has a plurality of protocol designation functions for transmission and reception with a terminal device, and a transmission and reception function that controls transmission via the terminal device and a transmission/reception unit according to each protocol. and a DMA circuit that transfers transmitted and received data between a buffer for storing transmitted and received data and the upper network using DMA, and a circuit dedicated to protocol control that determines which of the plurality of protocols is used in the circuit dedicated to protocol control. A designation switch that can be designated externally is provided.

[Effect]

According to the present invention, one protocol is designated by the designated switch, and the protocol control dedicated circuit transmits and receives data between the communication device and the terminal according to the designated protocol. Furthermore, although transmitted and received data is temporarily stored in a buffer within the communication device, data is transferred between the buffer and the network using a DMA circuit. This makes it possible to use communication devices without the need for a microcomputer inside the communication device.
It can achieve the original communication function as a communication device, and can also be used as a relay device between the communication device's network and the terminal device, and because it performs DMA transfer, it can perform high-speed transfer without putting a burden on the network or terminal device. do not have.

〔Example〕

FIG. 2 shows an overall system diagram of the present invention. Network 21 is called a high-speed network. There are communication devices 20a and 20b at both ends, and a network 21 performs communication between the communication devices 20a and 20b. Of course,
A huge number of other communication devices are connected in parallel to the network 21 .

The communication device 20a connects to the terminal device 23a via one line 22a.
The communication device 20b is connected to the terminal device 23b via the line 22b. Both terminal devices 23a and 23b are 1
or more.

In such a system, data is transmitted and received between the terminal devices 23a and 23b. The communication devices 20a, 20b have the role of relaying communication with the terminal devices 23a, 23b.

There are multiple protocols such as control information between the terminal device 23a and the communication device 20a, but one is specified when deciding the system, and according to this specified protocol, the terminal device 23a and the communication device 20a', Communication between the two is performed via the line 22a.

There are multiple protocols between the terminal device 23b and the communication device 20b, and one of them is specified at the time of system determination, and the terminal device 2
Communication between the communication device 3b and the communication device 20b is performed via the line 22b.

The protocol between the communication device 20a and the network 21, the protocol within the network 21, and the protocol between the network 21 and the communication device 20b take completely different formats, but they are not directly related to the present invention. , omitted.

The lower part of FIG. 2 shows the transmission time t. Here, the transmission time is an amount that can also be called transmission capacity, and refers to the amount of bits or bytes that can be sent per unit time. For example, t
, =48Kbρs, t3=32Mbps.

On the other hand, t2 is the processing time in the communication devices 20a and 20b, and tz≧1. It is desirable that

Here, if t 1 = 48 K bps, t2
=48 Kbps is not possible with the conventional communication device 20a (or 20b) with a built-in microcomputer. It is necessary to first determine the protocol procedure between the terminal device 23a and the communication device 20a, and then to control the protocol procedure using software after this determination. Processing speeds of 48 K bps are not achievable for performing this procedure.

Therefore, in this embodiment, a microcomputer is not built into the communication devices 20a and 20b, and the communication device is formed from dedicated hardware. In such a dedicated hardware communication device, the protocol with the terminal device is uniquely specified at the time of system determination, and data transmission between the network and the communication device is performed at high speed using DMA transfer. Based on this uniquely specified protocol, protocol operations are simplified and shortened, and high-speed transfer is possible using DMA transfer, so the actual processing speed in the communication devices 20a and 20b is improved. However, t2≧tl can be achieved.

FIG. 1 shows an example diagram of a communication device 20a. The communication device 20b also has the same configuration6.The communication device 20a has a network interface control unit 30. Internal bus 31. DMA circuit 32. Protocol control circuit 33. DMA interface circuit 34° protocol specification switch 35. Data buffer 36° receiving circuit 37. Transmission circuit 39. It consists of an internal bus 39.

The features of this embodiment include the provision of a DMA circuit 32 and a DMA interface circuit 34 for managing DMA transfer, the provision of a protocol control circuit 33 consisting of dedicated hardware, and the provision of a protocol specification switch. It is. Furthermore, the use of data buffer 36 is also new.

It will be explained in further detail.

The protocol control circuit 33 specifies and controls a control protocol with the terminal device 23a on the transmission line 22a.

This protocol has two control procedures: a BISYNC procedure and an HDLC procedure. When using, specify one of the procedures. This specification is made when determining the system. The protocol designation switch 35 specifies this procedure.

When specified by this protocol designation switch 35, the protocol control circuit 33 takes charge of one of the specified protocols, either the B-5YNC procedure or the HDLC procedure, and according to this procedure, communicates with the terminal device 23a. Transmission is performed between

The data buffer 36 temporarily latches the data received via the receiving circuit 37 and then transmits the data to the network 21 . Further, the data received from the network 21 is temporarily latched in the data buffer 36 and then sent to the terminal device 23a via the transmission circuit 38.

This data transfer between the data buffer 36 and the network 21 is a DMA transfer, and this DMA transfer is a DMA transfer.
This is done according to instructions from the A circuit 32.

The operations of the protocol control circuit 33, DMA circuit 32, and DMA interface circuit 34 in the above operation will be further described.

The protocol control circuit 33 takes in the data received by the reception circuit 37 via the bus 39, performs a CRC check,
If it is determined that the data is correct, the CR is redundant data.
C code etc. are removed from the data, only necessary data is extracted and sent to the data buffer 36. The DMA interface circuit is notified that the data has been latched in the data buffer, and then the DMA interface circuit 34
issues a reception request to the DMA circuit 32, and upon receiving this request, the DMA circuit 32 reads out the data in the data buffer 36 and transfers the data to the bus 31. It is sent to the network 21 via the network interface control unit 30.

On the other hand, the data sent from the network 21 is
The data is temporarily taken into the network interface control unit 30. The DMA interface circuit 34 knows this and
A capture command is given to the DMA circuit 32. DMA circuit 32
extracts data from the network interface control unit 30 and stores it in the data buffer 36. After storage, the data is sent to the protocol control circuit, and the protocol control circuit 33 adds CRC data to this data and sends it to the terminal device 23a via the transmission circuit 38 and line 22a.

The internal functions of the protocol control circuit 33 are shown in FIG. B
It has two protocol functions, an ISYNC procedure and an HDLC procedure, and an external protocol designation switch 35 designates one of them. After specifying, the procedure is limited to one or the other. In the BISYNC procedure, SYN removal or S
For any instructions for YN insertion and for HDLC procedures,
Instructs whether to remove zero or insert zero. In either procedure, CRC generation or CRC check is performed. Note that SYN insertion, zero insertion, and CRC generation are transmission modes, and SYN insertion, zero insertion, and CRC generation are transmission modes.
N removal, zero removal, and CRC check mean reception mode.

In this embodiment, two procedures were selected, but the protocol is not limited to these two procedures because there are other procedures. Naturally, processes other than SYN removal and insertion, zero removal and zero insertion are also possible.

〔Effect of the invention〕

According to the present invention, a communication device capable of high-speed processing can be provided because the protocol can be determined only by a designated switch from the outside and data transfer to and from the network is performed using DMA transfer.

[Brief explanation of the drawing]

Fig. 1 is an embodiment diagram of the present invention, Fig. 2 is an overall system diagram,
FIG. 3 is an internal functional diagram of the protocol control circuit. 20a, 20b-communication control device, 23a, 23
b One terminal device. Representative Patent Attorney Tadashi Akimoto Business 1st 3rd Diagram

Claims (1)

[Claims] 1. A transmitting/receiving unit that performs transmission and reception with a terminal device, a plurality of protocol specification functions for transmitting and receiving data with the terminal device, and a function of specifying a plurality of protocols for transmitting and receiving data between the terminal device and the transmitting/receiving unit according to each protocol. a dedicated protocol control circuit having a transmission/reception control function for controlling transmission/reception via the transmission/reception unit; and a dedicated protocol control circuit having a transmission/reception control function for controlling transmission/reception via the transmission/reception unit; a DMA circuit that performs transmission/reception data transfer between the buffer and the upper network using DMA; A communication device for coupling between a terminal device and a network, which includes a designated switch that is designated from outside a dedicated circuit for protocol control.