JPS59197919A - Collision preventing system - Google Patents

Abstract

PURPOSE:To inhibit a delayed signal so as to make control of an input interface easier, by installing a logical means which prevents initial selection from a data channel device and asynchronous status report from a processor from colliding against each other. CONSTITUTION:An MPU1, ROM2, RAM3, plural peripheral devices 5, and a channel interface controlling section 4 connected with a data channel device DCH are connected with the data bus 6 of an input-output controlling device. An FF10 which is set by means of initial selection from the device DCH, gates 7 and 8 consisting an MPU lead, and FF9 which inputs an asynchronous signal RPASY from the MPU1 and the output of the gate 8 are installed to the controlling section 4. At the controlling section 4, collision between the initial selection from the device DCH and the signal RPASY from the MPU1 is prevented and either one of them, which is delayed than the other, is inhibited. Thus the control of an input interface is made easier.

Description

Detailed Description of the Invention +a) Technical Field of the Invention The present invention relates to a channel interface control section of an input/output control device controlled by a microprocessor sensor.
This invention relates to a method for preventing a collision between an asynchronous status report from an input/output device and an initial selection for the input/output device from a data channel device.

(b) Background of the technology With the recent increase in the number of input/output devices due to the increase in the size of data processing devices and the application to various devices due to the trend of full-scale introduction of microprocessors, the need for input/output control devices has increased. As applications have become more conceivable, new developments have become necessary in the interface control between the data channel device and the input/output device in the input/output control device.

(C1 Prior Art and Problems Conventionally, well-known input/output control devices were controlled by wiring logic, and the number of connected input/output devices was small. Selection (Command Address Word (CAW)
5 fetch, signal exchange with the input/output control device in the startup sequence after completion of channel command word (CCW) fetch] and asynchronous status report from the input/output device (
Collisions with various activation signals from input/output devices did not pose any problems. In other words, priority processing based on wiring logic,
This could be handled by sending and receiving input/output interface signals based on the response confirmation method.

However, with the recent increase in the size of data processing devices, the number of input/output devices has increased, and the input/output control devices have come to be controlled by microprocessors, causing problems in handling the collision of mutual signals. It's starting to look like this. That is, status reporting from input/output devices is performed simultaneously by a large number of input/output devices, and the input/output control device is a microprocessor that operates independently of the data channel device.
Therefore, even if the asynchronous status signals from the input/output devices are synchronized with the microprocessor sensor, there is essentially a problem that the microprocessor sensor and the data channel device remain out of synchronization.

fd) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides an input/output control device controlled by a microprocessor sensor to prevent collision between an asynchronous status report from a microprocessor sensor and an initial selection from a data channel device. The purpose is to provide a method.

+81 Structure and object of the invention According to the present invention, in an input/output control device controlled by a microprocessor sensor, a channel interface control section provided between the microprocessor sensor and a data bus logical means are provided to prevent a collision between an asynchronous status report of an input/output device sent through the microprocessor and an initial selection from a data channel device; Control busy is reported for the initial selection from the device to give priority to the asynchronous status report, and if the initial selection from the data channel device is early, the address out signal, which is one of the input/output interface signals, is This is achieved by providing a control method in which the initial selection bit is turned on and inputted to the collision prevention means at the time when the ARATOI signal is received, and the asynchronous status report from the microprocessor is suppressed. be done.

ffl Embodiments of the Invention The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an input/output control device controlled by a microprocessor related to the present invention, where 1 is a microprocessor (hereinafter referred to as MPυ), 2 is a read-only memory (ROM), and 3 is a microprocessor-controlled input/output control device. 4 is a random access memory (RAM), 4 is a channel interface control unit incorporating collision prevention means, which is the main focus of the present invention, 5 is a peripheral device (hereinafter referred to as PU), and 6 is a data bus. Therefore, the parts that fall under the category of so-called input/output control devices are those other than the PU 5.

In this input/output control device, an MPU 1 reads microinstructions from a read-only memory (ROM) 2 through a data bus 6, and uses the microprogram to read various data coming from a PU 5 and a channel interface control unit 4. The data is temporarily stored in a random access memory (RAM) 3 via a data bus 6 to perform desired input/output control.

The present invention provides initial selection from a data channel device (DCH) connected to the channel interface control unit 4 and asynchronous status information from the PU 5 that is processed by the MPU 1 and sent to the channel interface control unit 4. The main focus is on a circuit configuration that prevents collisions with reports, and is provided in the channel interface control section 4.

FIG. 2 shows an example of its specific configuration, which has seven tubes.

To explain the logical operation in this figure with reference to FIG. 1, when the initial selection is activated from the DCH, the initial selection bit (SELTD
) 10 is set. When MPLI 1 reads this, the read signal 1? EAD is input to the AND circuit 8, and the initial selection bit (SBLT
D) 10 is ANDed with the output signal inverted by the NOT circuit 7, and as a result, the flip-flop 9 is not sent, and the output signal of the flip-flop 9, the PASY signal (the input signal to be processed by the MPU 1), is It already has status information from the output device, and the signal for inhibiting initial selection activation from the DCH remains off.

If MPU 1 is this initial selection pin)
(SELTD) When reading the 10 signal, if the signal is not on, the output of the inverter 7 is logic “1”.
”, the AND circuit 8 performs an AND with the read signal READ from the MPU 1, sets the flip-flop 9, and turns on the PASY signal.

The present invention prioritizes the initial selection from DC) or the asynchronous status report from MPU 1, depending on whether the above-mentioned PASY signal in the collision prevention circuit provided in channel interface control section 4 is turned on by a microprogram. It is for deciding whether to give priority to

Figure 3 shows a time chart of the main input/output interface signals in the channel interface control unit 4. (A) indicates the case where the initial selection from the DCH is early, and the asynchronous status report from the MPU 1 is early. Cases are shown in (b).

In the figure, ■ indicates the command address word (CAW) fetch in DC)l, and ■ indicates the channel command (C(W)) fetch by the command address word (CAW).
) indicates a fetch, and ■ indicates an initial selection related to the present invention.

In the initial selection operation (2), address out (ADO) and select out (SLO).

Operational In (OPI), Address In (ADI), Command Out (CMO), Status In (STI), Service Out (SVO)
, bus out (BO), and bus in (Bl) are operated according to a known input/output interface, so they will not be particularly explained here. ) 10 and the operation of the above-mentioned PASY signal, (a) is a case where the initial selection from DCH is early, and when address out (ADO) and select out (SLO) are received, the initial selection bit (SELTD) 10 Turn on.

The microprogram in MPU 1 always checks the presence or absence of this initial selection bit (SI!LTD) 10 signal before reporting the asynchronous status of the input/output device, and
LTD ) 10 is on, the PASY signal is not output according to the logic explained in FIG. 2, so asynchronous status reporting by the main microprogram υ1 can be suppressed.

This initial selection bit (SELTD)
lO is the channel interface control unit 4 that receives the command out (CMO) signal and bus out (BO) from the DCH.
) In order to have the MPU process the command sent to the line,
It is controlled to issue an interrupt to the MPU and reset when the MPU finishes processing this command interrupt.

(b) is a case where the asynchronous status report from the MPU microprogram is early, and when the microprogram reads initial selection bit (SELTD) 10, only when this signal is off, the logic explained in Figure 2 is applied. Accordingly, if the PASY signal is turned on and there is an initial selection from the DCH at this point, the channel interface control unit 4 reports control busy to the DCH [Specifically, in the channel interface control unit 4, the hardware Status In (STI) signal is reported] and the DCH
from.

Controlled to cancel the initial selection. This PASY signal is controlled by the microprogram of the MPU so that an asynchronous status report is sent to the DCH through the channel interface control section 4, and when the related processing is completed, an RPASY is sent to the channel interface control section 4 for resetting.

(g> Effects of the Invention As explained in detail above, according to the present invention, in the channel interface control section of the input/output control device controlled by the microprocessor, initial selection from the data channel device, microb, and processor By providing logic means to prevent collisions with asynchronous status reporting of the The microprocessor sensor, which operates with a clock different from that of the channel device, also has the effect of easily controlling the input/output interface.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an input/output control device controlled by a micropro sensor, Figure 2 is a diagram showing one embodiment of a collision prevention circuit, which is the main focus of the present invention, and Figure 3 is a block diagram of an input/output control device controlled by a microprocessor sensor. FIG. 3 is a time chart diagram of input/output interface signals when the present invention is implemented. In the drawing, 1 is a microprocessor, 12 is a read-only memory (ROM), 3 is a random access memory (RAM), 4 is a channel interface control unit, 5 is a peripheral device, and 6 is a data bus 15ELT.
D indicates an initial selection bit, and PASY indicates a signal for inhibiting initial selection from the data channel device.寥 1 time A5γ rate 2 figure fist 3 figure

Claims (1)

[Claims] In an input/output control device controlled by a microprocessor, an asynchronous status report of the input/output device sent from the microprocessor through a data bus to a channel interface control unit provided between the microprocessor and the data channel device; providing logic means for preventing a collision with an initial selection from a data channel device, and reporting a control busy for the initial selection from the data channel device if the asynchronous status report from the microprocessor sensor is early; If the asynchronous status report is given priority and the initial selection from the data channel device is early, an initial selection bit is turned on at the time of receiving an address out signal and a select out signal, which are one of the input/output interface signals, A collision prevention method, characterized in that the collision prevention method is controlled by inputting information to the collision prevention means to suppress an asynchronous status report from the microprocessor sensor.