JPS63263514A - Balanced/unbalanced converter for scsi bus - Google Patents

Abstract

PURPOSE:To connect a balanced SCSI (small computer system interface) device and an unbalanced SCSI device to each other by starting an SCSI protocol controller having an identification name through a bus to perform communication between SCSI protocol controllers at the time of setting this identification name to a destination storage part of an SCSI protocol controller. CONSTITUTION:In case of communication from a device #k on a balanced SCSI bus to a device #k+l on an unbalanced SCSI bus, a request flows to the SCSI bus from the device #k on the balanced SCSI bus, and an SCSI protocol controller having the identification name #k+l receives this request. Then, the identification name #k of the transmission source is set to the destination ID storage part. A microprocessor finds the identification name #k of the device of the transmission source by the interrupt from the SCSI protocol controller having the identification name #k+l and sets the SCSI protocol controller having the identification name #k to the transmission state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a balanced/unbalanced conversion device for a SCSI bus that interconnects a balanced SCSI device and an unbalanced 5cSf device.

(Prior art) S CS I (sa+all computers
system 1ninterface) is a parallel bus interface for small computers, and is currently an ANSI
X3T9.2 is promoting standardization.

There are two types of SCSI devices:

(2) Balanced SCSR device This device uses a transmission line in which the potentials on the two conductors are equal with respect to the ground and are symmetrical with respect to the ground point. The maximum extension distance is 25m, which is long, but two Shin@ lines form a set, which increases equipment costs.

■ Unbalanced 5CSR device 2 - This refers to a device that uses a transmission line in which the potentials on the conductors are not equal with respect to the ground. If there is a grounding wire, only one signal wire is required, which reduces equipment costs, but the maximum extension distance is short at 6m.

(Problem to be solved by the invention) However, as far as the applicant currently knows, the balanced type S
There is no device that interconnects the CSI devices and unbalanced SCSI devices.

Considering the case where the system becomes widespread, if the two types coexist and cannot be interconnected, an unfavorable situation will occur in terms of system construction.

The present invention solves these problems, and the balanced type S
An object of the present invention is to provide a balanced/unbalanced conversion device for a SCSI bus that interconnects a CSI device and an unbalanced SCSI device.

(Means for solving the problem) The first invention that achieves this purpose is a balanced 5cs
Balanced transceivers that exchange data with devices connected to the r bus, unbalanced transceivers that exchange data with i devices connected to the unbalanced SCSI bus, and balanced and unbalanced types of these It consists of a SCSI protocol controller that is attached one-to-one with each of the transceivers, and a bus that interconnects the balanced and unbalanced transceivers via these SCSI protocol controllers.

To explain the details of the SCSI protocol controller, if the transceiver is a balanced type, a unique identification name corresponding to an unbalanced SCSI bus device is given; A unique identification name corresponding to the device is assigned, and an identification name setting section stores an identification name unique to this own station, and a data transfer request from another station is given an identification name that is the same as the identification name of the own station. It has a destination storage unit that stores the identification name of the destination when a call is made, and when an alias of the destination storage unit is set, it activates the SCSI protocol controller of the corresponding identification name. It was designed to communicate between them.

The second invention that achieves this purpose is a balanced SCS.
A balanced transmitter/receiver that exchanges data with devices connected to the I bus, and an ELL connected to an unbalanced SCSI bus.
An unbalanced transceiver that sends and receives data to i, a SCSI protocol controller that is attached one-to-one to each of these balanced and unbalanced transceivers, and a DMA transfer by interconnecting these 5csr protocol controllers. A bus switching unit monitors the transmission/reception status of these SCSI protocol controllers and establishes a data bus for communication.

To explain the details of the bus switching section, the S
As a bus for connecting between CSI protocol controllers, the DMA bus is selected during the SCSI data transfer phase, and the processor bus is selected during the SCSI message, command, and status phases.

(effect) Each component of the first invention operates as follows.

First, devices connected to a balanced SCSI bus have a unique identification name, and devices connected to an unbalanced SCSI bus also have a unique identification name.

The balanced and unbalanced transceivers are connected to the balanced and unbalanced SCSI buses, respectively, so that they can communicate with each of the three devices.

When a SCSI protocol controller is connected one-to-one with a balanced transceiver, it has an identification name for associating it with a device connected to an unbalanced SCSI bus. Also, SC
When an SI protocol controller is connected one-to-one with an unbalanced transceiver, it has an identification name for associating it with a device connected to a balanced SCSI bus.

When a communication request is made from a device on the balanced SCSI bus side to a device on the unbalanced SCSI bus side, the SCSI protocol control corresponding to the identification name of the requested device on the unbalanced SCSI bus side is performed via the SCSI bus. The corresponding 5CSI protocol controller is specified based on the identification name of the contents of the destination storage section of this station (equipment on the balanced SCSI bus side). In this manner, the use of the DMA bus and processor bus connecting between the 8081 protocol control II devices is enabled, allowing direct communication of devices connected to the SCSI bus.

Each component of the second invention operates as follows.

The same components as in the first invention have the same effect. The DMA bus is used exclusively for data transfer, which helps reduce communication time. The processor bus is used for data transfer when complex processing such as state phase is required. The bus switching unit switches combinations between the scst protocol controllers for the DMA bus and the processor bus.

(Example) The present invention will be explained below using the drawings.

FIG. 1 is a configuration block diagram schematically explaining the concept of an embodiment of the present invention. As shown, balanced scs
Computers and disks each having a unique identification name (10) are connected to the t-bus. For example, #1. #2. ..., there are a total of A corpses. Also connected to the unbalanced SCSI bus are computers, tapes, etc. each having a unique identification name. For example, tl+1. ..., #i+1, and the total is 1
There are several.

Balanced/unbalanced converter for SCSI bus is balanced SCSI
It is interposed between the bus and the unbalanced SCSI bus.

FIG. 2 is a block diagram conceptually showing the structure of a SCSI bus balanced/unbalanced conversion device.

The balanced SCSI bus has an SCS with an identification name corresponding to each of the 11 devices connected to the unbalanced SCSI bus.
I protocol system tilI device (SPC: SO8I pr
CD/R: SCSI
driver receiver) are installed in series.

According to the example in FIG. 1, the identification name of the SCSI protocol controller is #A+1. ..., +1 is added to #.

Note that the 5CSI protocol system t11fi can be obtained, for example, as M B 87030 supplied by Fujitsu Limited.

An unbalanced SCSI bus has an identification name that corresponds to each device connected to the balanced SCSI bus.
A protocol controller (SP(2)) and an unbalanced transmitter/receiver (D/R>) attached one-to-one are installed in series. According to the example in Figure 1, the SCSI protocol controller The identification names are #1, #2, ..., #k.

DM, A bus is all 5cst protocol controller #1
．． ..., #i+1 are connected. The processor bus also includes all 5csr protocol controllers #1.・・・
・, #A+7 are connected. The SC8■ protocol controller and the transmitter/receiver are connected by a bus that is a multiplex of these DM△ buses and the processor bus.

A microprocessor (MPU) and memory (r (AM and ROM) are also connected to the processor bus.
U monitors the transmission/reception status of the SCSI protocol controller and manages the communicating devices.
scs bus for connecting between tIIIllll devices
In the data transfer phase of t, the relevant DMA bus is selected and S
During phases such as CSI message, command, and status, it operates as a bus switching unit that selects the relevant processor bus.

FIG. 3 is a block diagram of the configuration of the transmitting and receiving circuit of the new type SCSI bus. For transmission, an element such as 1838 is used for each pit of the output parallel data bus 5DBO. For reception, input parallel data bus SDB I
A device such as 3240 is used for each pit.

FIG. 4 is a block diagram of a transmission/reception circuit for a balanced 5CSR bus. Parallel data bus 8080 for output
A transmitting element is provided for each bit, a receiving element is provided for each bit of the input parallel data bus SDBI, and a parallel data bus 5D8 for output enable is provided.
E is supplied to these transmitting elements.

Figure fj15 is a block diagram of the configuration of the SCSI protocol ljJ III device. In the figure, reference numeral 11 denotes a transfer control unit that supplies information necessary to perform bus transfers, and controls, for example, request signals and acknowledge signals. Reference numeral 12 denotes a phase control unit that supplies information necessary to control the phase of the bus, such as message signals, command signals, and status signals.
I'll do it. Reference numeral 13 denotes a bus exclusive right contention management unit that supplies information necessary for bus management, and controls the select signal and busy signal to control contention on the SCSI bus.

14 is a data transfer counter that manages the number of data transfers executed by the transfer control unit 11. Reference numeral 15 denotes a data buffer that adjusts the input/output speed when transferring data from the transceiver to another transceiver or data buffer. 16 is the winner! as
cs I An IO setting section that stores the identification name of the protocol I controller. This identification name is supplied from the MPU at startup, for example, or is set in advance using a DIP switch or the like.

17 were connected via the bus! A device, and the s
This is a destination IQ storage unit that stores the identification name of the device that selected the cst protocol-based aS. Reference numeral 18 denotes an interrupt signal generating section for temporarily stopping the operation of the MPtJ and giving priority to interrupt processing, and is activated when an identification name is written in the destination ID storage section 17, for example.

Furthermore, when the identification name is written to the destination storage unit 17, the processor learns the identification name through the processor bus,
In this case, in FIG. 1, a device with the same identification name as the ill device that sent the illumination is transferred from the #tiger device on the balanced SCSI bus to # on the unbalanced SCSI bus. For example, let's take the case of communicating with a device. As shown in Figure 2, # of the balanced SCSI bus
A request flows from device A to the SCSI bus, with the identification name #Niwa+! The SCSI protocol controller receives this. Then, the identification name # of the sender is set in the storage unit 17 of the destination 10. Next, the microprocessor uses the identification name #corpse+
! It learns from the interrupt from the SCSI protocol controller that the originating device's identification name is #, and sets the SCSI protocol controller with identification name # to the sending state.

In this way, the communication bus connects device #A to transmitter/receiver #1! ~ Transmitter/receiver # Corpse ~ Ia device # mud ten! and is established.

The MPU operates as a bus switching unit, and when transmitting and receiving information without performing any processing on the data, such as in DMA transfer, high speed is achieved using the DMA bus. Furthermore, when appropriate processing is required depending on the data, such as with stator signals, the processor bus is used to enable the microprocessor to process data exchange.

(Effect of the invention) As explained above, the present invention has the following effects.

■ By configuring the SCSI bus balanced/unbalanced conversion device as in the first and second inventions, it is possible to communicate with devices connected to a balanced SCSI bus and devices connected to an unbalanced SCSI bus. become.

(2) If a plurality of buses are provided and used by switching according to information as in the second invention, the data transfer time by the SCSI bus balanced/unbalanced converter can be shortened.

■ If the communication bus is established using the communication function of the devices connected to the SCSI bus as in the example, the load on the MPU is extremely light, and the balanced/
When recognizing an unbalanced converter, it is transparent (transpar).
ent > , i.e. balanced (or unbalanced) SCS
It is difficult to handle because it can be handled in exactly the same way when communicating between II devices and when communicating between a balanced SCSI device and an unbalanced 5csr device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically explaining the concept of an embodiment of the present invention. FIG. 2 is a block diagram conceptually showing the structure of a balanced/unbalanced converter for an SCS Figure 3 is a configuration block diagram of the transmission/reception circuit of an unbalanced SCSI bus, Figure 4 is a configuration block diagram of the transmission/reception circuit of a balanced SCSI bus, and Figure 5 is a configuration block diagram of the transmission/reception circuit of the unbalanced SCSI bus.
FIG.

Claims (2)

[Claims] (1) Balanced transceivers that exchange data with devices connected to a balanced SCSI bus, unbalanced transceivers that exchange data with devices connected to an unbalanced SCSI bus, and these balanced types. If the transmitter/receiver is a balanced type, a unique identification name corresponding to the equipment on the unbalanced SCSI bus is given, and if the transmitter/receiver is an unbalanced type If so, it is a balanced SC.
an identification name setting unit that assigns a unique identification name to a device on the SI bus and stores an identification name unique to its own station;
A SCSI protocol controller having a destination storage unit that stores the identification name of the destination when a data transfer request from another station sends an identification name that is the same as the identification name of the own station; a bus that connects the balanced and unbalanced transceivers to each other via a controller, and when an identification name is set in the destination storage unit of the SCSI protocol controller, A SCSI device characterized in that a SCSI protocol controller with a corresponding identification name is activated to communicate between them.
Bus balanced/unbalanced converter. (2) Balanced transceivers that exchange data with devices connected to a balanced SCSI bus; unbalanced transceivers that exchange data with devices connected to an unbalanced SCSI bus; and an unbalanced transceiver, and if the transceiver is a balanced type, a unique identification name corresponding to the unbalanced SCSI bus device is given. Balanced SCS if available
An identification name setting section that assigns a unique identification name to each device on the I-bus and stores an identification name unique to the own station, and a data transfer request from another station is assigned an identification name that is the same as the identification name of the own station. A SCSI protocol controller having a destination storage unit that stores the identification name of the destination when the name is transmitted, and the balanced type and unbalanced type transceiver are interconnected via these SCSI protocol controllers. DM processor buses and these SCSI protocol controllers are interconnected.
During the SCSI data transfer phase, a bus is used to connect the DMA bus used for A transfer and the SCSI protocol controller that monitors the transmission/reception status of these SCSI protocol controllers and manages the communicating devices.
a bus switching unit that selects a bus and selects the processor bus in phases such as SCSI messages, commands, and status, and when an identification name is set in the destination storage unit of the SCSI protocol controller, A SCSI bus balanced/unbalanced conversion device characterized in that a SCSI protocol controller having a corresponding identification name is activated via a processor bus to communicate therebetween.