JPH04139935A - Serial interface system - Google Patents

Abstract

PURPOSE:To transmit and receive a data between devices serially without losing real time performance with simple control and configuration by sending an interrupt request signal to a predetermined time slot in an interrupt request signal line and allowing a controller to start data transmission and reception with each device based thereon. CONSTITUTION:A controller 1 and plural devices 21-m2, 31-3n are interconnected by an address signal line, an input output data line, each enable signal line for data input output and an interrupt request signal line from the devices 21-2m, 31-3n. Then information giving a transmission timing of various signals is fed from the controller 1 to the devices 21-2m, 31-3n. and an interrupt request signal fed to the devices 21-2m, 31-3n and the controller is allocated to a different time slot on the interrupt request signal line respectively. Thus, data transmission reception is implemented without losing the real time performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a serial data interface system suitable for relatively small-scale systems such as attitude control equipment for spacecraft, for example.

[Prior Art] In the attitude control equipment of a spacecraft, data is frequently exchanged between the attitude control device, various sensors such as a solar sensor, inertial sensor, and stellar sensor, and various actuators such as a momentum wheel and a reaction control system. An exchange takes place. Conventionally, data interfaces between devices used in such systems include data buses and NIL-STD-1553 for command and data transfer.
9. Standardized systems such as LAN (IEEE802.4) are adopted.

These are all interfaces that perform serial digital data transmission using one or two pairs of HOT/RET signals, and have the advantage that they can be configured with a small number of interface lines.

[Problems to be Solved by the Invention] However, the conventional serial interface method described above reduces the number of interface lines and
In order to accommodate various applications, the functions of interface circuits have become complex. For this reason, there is a problem in that the processing requests of each device cannot be detected promptly, and real-time performance is lacking. Therefore, there is a problem in that it is not suitable for systems that are relatively small-scale and require real-time performance, such as the attitude control system of a spacecraft.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a serial interface system that has a simple configuration and is excellent in real-time performance.

[Means for Solving the Problem] A serial interface method according to the present invention is a serial interface method for transmitting and receiving data between a control device and a plurality of devices. , an address signal line, an input/output data line, a data input/output enable signal line, and an interrupt request signal line from each device, and the timing of sending various signals from the control device to each device is controlled. The present invention is characterized in that the interrupt request signals supplied from the respective devices to the control device are respectively assigned to different time slots of the interrupt request signal line.

[Operation] According to the present invention, the control device and a plurality of devices transmit and receive data in synchronization with information output from the control device that provides the transmission timing. When each device sends an interrupt request signal to the control device, the interrupt request signal is sent to a predetermined time slot on the interrupt request signal line. The control device starts sending and receiving data to and from each device based on the interrupt request signal that is input in a time-sharing manner and determines the priority as necessary, so data can be sent and received without sacrificing real-time performance. can be sent and received.

Further, in the present invention, the control device and each device are connected by an address signal line, an input/output data line, each data input/output enable signal line, and an interrupt request signal line from each device, and the control device The above-described operation can be realized with a simple system configuration in which information indicating timings for sending out various signals is supplied to each of the devices.

[Embodiments] Hereinafter, embodiments of the present invention will be described based on the attached drawings.

FIG. 1 is a block diagram showing the configuration of a spacecraft attitude control system to which a serial interface method according to an embodiment of the present invention is applied.

This system consists of an attitude control device 1 that controls the system.
, various sensors 2□-2□ such as solar sensors, inertial sensors, and star sensors, and various actuators such as momentum wheels and reaction control systems 3. 3n and a bus 4 that connects them.

Next, various signals transmitted and received on the bus 4 will be explained with reference to FIGS. 2 to 4.

As shown in FIGS. 2 to 4, the clock signal CK is
For example, a signal having a frequency of 524.288 kHz gives the basic timing of the system, and is transmitted from the attitude control device 1 to each sensor 2I to 2□ and each actuator 3. ~3n is supplied.

As shown in FIGS. 2 and 3, the address enable signal AE is transmitted from the attitude control device 1 to each sensor 2□ to 2I, .
and is outputted to each actuator 3□ to 3n, giving timing for transmitting address information.

The data enable signal DB is transmitted from the attitude control device 1 to each sensor 21-2. ．． ．． and is outputted to each actuator 3□ to 3n, giving timing for transmitting input/output data.

The output data DO is transmitted from the attitude control device 1 to each sensor 21 to
2□ and the data output to each actuator 3, to 3□, the address data output at the sending timing of the address enable signal AE and the data enable signal D.
It is composed of output data output at the sending timing of E. Address data consists of, for example, 8-bit serial data, of which the MSB (most significant bit) is information that distinguishes between output mode and input mode, and the remaining 7 bits specify one of the 127 devices. address information. Here, as shown in Figure 2,
Output mode when MSB of address data is “OII”
Similarly, as shown in FIG. 3, the input mode is set when the signal is "'1".The output data is composed of, for example, 16-bit serial data.

Input data Dr is transmitted to each sensor 21-2 and each actuator 3I-3. at the sending timing of data enable signal DE. ．． The data is sent from the controller to the attitude control device 1, and is composed of, for example, 16-bit serial data.

Note that the 4 clocks between the address and input/output data are:
This is a preparation period for each device to decode the address, identify whether it is in input mode or output mode, and input or output data.

Further, the interrupt request timing signal IRT is transmitted from the attitude control device 1 to each sensor 2. ~2□ and each actuator 3I~
It consists of 8-bit serial data output to 3o, and provides the timing of an interrupt request. The MSB of this signal IRT is fixed to II I 11, and the timing signal IRT is identified by the rising timing.

The remaining 7 bits are data indicating the interrupt channel for which interrupts are permitted.

Furthermore, the interrupt request signal IRB on the interrupt request path line is
Each sensor 21-2. ．． ．． and each actuator 31 to 3
The device that sends the interrupt request sends an IIO11 level interrupt request in the time slot assigned to itself. Here, it is possible to send interrupt requests for 16 channels of Ro-R15.

Next, the operation of this system will be explained.

FIG. 2 is a timing diagram of the output mode.

When outputting data from the attitude control device 1 to a specific device, first, the address enable signal AE is set to the "1" level and an address that specifies the device on the other side is output. Since the MSB of is "0", it knows that the data will be output from the attitude control device 1, and from the remaining 7 bits of the address, it knows that the data is addressed to itself. As a result, the data from the attitude control device 1 will be input to the device specified in item 1.

FIG. 3 is a timing diagram of the input mode.

When the attitude control device 1 receives data from a specific device, it first sets the address enable signal AE to "'1" and outputs an address that specifies the device on the other side. The MSB of the address is “+1”
”, it knows that the attitude control device 1 is requesting data, and from the remaining 7 bits of the address, it knows that the data is from itself.Thus, “1. The specified device sends output data,
When the attitude control device 1 accepts this, the data input mode ends.

FIG. 4 is a timing diagram showing interrupt request processing of each device.

That is, the attitude control device 1 outputs the interrupt request timing signal IR at a predetermined period of, for example, about 200 μs to 1 ms.
Output T. Since the MSB of the interrupt request timing signal IRT is fixed at "31," the interrupt request timing signal IRT is detected by each device at the timing of its rise.

On the other hand, the interrupt request pass line is normally fixed at a high level, and each device that sends an interrupt request switches this pass line to 1 at a specific timing assigned to it.
Bring it down to 101+ level.

The attitude control device 1 checks the interrupt request signal IRB, confirms how many channels of interrupt requests are being sent, and determines the priority level to determine which channels should be allowed to interrupt. This determined channel is indicated by the remaining 7 bits of the interrupt request timing signal IRT.

The device of the channel for which the interruption permission has been received sends and receives data to and from the attitude control device at the timing of the input mode or exit mode described above. On the other hand, for devices on channels for which interrupts are not permitted, their interrupt request signals are reset and they send out interrupt requests again.

In this way, according to this system, each device sends an interrupt request to a predetermined time slot,
It is possible to receive a response from the attitude control device 1 in substantially real time, and its configuration can be made simple.

"Effects of the Invention" 2. According to the present invention, data is sent and received between a control device and a plurality of devices in synchronization with information output from the control device that provides the transmission timing, When each device sends an interrupt request signal to the control device,
Simple control and configuration in which an interrupt request signal is sent to a predetermined time slot on the interrupt request signal line, and the control device starts sending and receiving data with each device based on this interrupt request signal. This has the effect that data can be serially transmitted and received between devices without impairing real-time performance.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of a spacecraft attitude control system to which a serial interface method according to an embodiment of the present invention is applied, Fig. 2 is a timing diagram of the output mode in the system, and Fig. 3 is a diagram showing the configuration of the spacecraft attitude control system in which the serial interface method according to the embodiment of the present invention is applied. Timing diagram of input mode. FIG. 4 is a timing diagram showing interrupt request processing of each device. 1; Attitude control device, 21~2m; Sensor, 3°~3□1

Claims (2)

[Claims] (1) In a serial interface method for transmitting and receiving data between a control device and multiple devices, address signal lines, input/output data lines, and data input/output lines are connected between the control device and multiple devices. It is connected by an enable signal line and an interrupt request signal line from each device, and the control device supplies information on the sending timing of various signals to each device, and from each device to the control device. A serial interface system characterized in that supplied interrupt request signals are assigned to different time slots on the interrupt request signal line. (2) The serial interface method according to claim 1, wherein the control device grants interrupt permission to interrupt request signals from each device according to their priorities.