JPH0752432B2 - Serial interface controller - Google Patents

Description

DETAILED DESCRIPTION [Outline] In a control device that sequentially calls a plurality of devices to exchange signals (data) by control of a polling method,
Even if the device is not connected to the corresponding address in the past, or if it is connected but the device is not in the operable state due to the power not being turned on, etc. Therefore, polling is performed by sequentially issuing addresses corresponding to all devices connectable to the connection device. Therefore, there is a problem that an invalid time is generated during polling and the signal transfer efficiency is poor. In order to solve such a conventional problem, the present invention provides a flag indicating whether or not a device is actually connected to suppress polling to a device that is not connected, and Providing a flag and a counter that indicate whether or not the device is in the operable state, and attempting to poll a device that is not in the operable state at a longer cycle than others in preparation for subsequent power-on, etc. Discloses a control method capable of performing efficient polling.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a control device for exchanging signals with a plurality of devices by a polling method,
In particular, the present invention relates to a method for efficiently performing polling when there is a terminal to which the device is not connected or a device which is in an inoperable state because the power of the device is not turned on.

[Prior Art] FIG. 2 is a block diagram showing an example of a configuration of a serial interface control device of a conventional control device, in which 50 is a serial interface control unit, and 51 is a polling control in response to a polling command from a host. A polling control unit, 52 is a device address sending circuit, 53 is a counter, 54 is a register, and 55 is an input / output device.

In FIG. 2, at the time of polling, the device address of the device to be polled first is set in the register 54, and this is sent to the device address sending circuit 52 according to an instruction from the polling control unit 51, and this is sent to the device address sending circuit 52. Is sent to the input / output device by. Then, thereafter, the counter 53 updates the device address by adding "1" to the value of the register 54, and each time the device address is updated, polling is performed.

[Problems to be Solved by the Invention] As described above, in the conventional polling control method, the addresses of all the devices that can be connected to the control device at the time of polling are unconditionally set in order or in descending order. I was sending it out.

However, in practice, the device is rarely used by being connected to the full capacity of the connected device, and normally, there are many addresses to which the device is not connected.

Even if the device is connected, there may be no response because the device is not powered on.

Conventionally, at the time of polling, the address to which the device is not actually connected and the address to which the device is inoperable are uniformly transmitted, so that the polling efficiency is improved by performing the completely invalid polling. There was a problem of being damaged.

In view of such problems of the related art, the present invention is capable of performing efficient polling, and for a device which is connected but is not in an operable state at the time of power-on, etc. It is an object of the present invention to provide a control method capable of detecting this when it becomes operable.

[Means for Solving the Problems] According to the present invention, as described in the claims, the above-described object is to perform address transmission to a plurality of devices in order, thereby enabling a specific device to operate. A serial interface control device for exchanging signals between the plurality of devices, the first flag indicating a connection state with the serial interface control device in association with each address given to the plurality of devices, and the plurality of the plurality of devices. A second flag indicating the operating state of the device and a counter for address transmission control are provided, and
At the time of address transmission, when both the first and second flags corresponding to the address to be transmitted are off, means for suppressing the address transmission and the first flag corresponding to the address to be transmitted are on, When the second flag is off, means for suppressing address transmission until the counter counts a predetermined value is achieved.

[Operation] In the above means, at the time of polling, by referring to the flag indicating whether or not the device is connected, if it is indicated that the device is not connected, transmission of the corresponding address is suppressed, and the next Since it is possible to start the processing relating to polling, invalid polling is not performed, and it is possible to shorten the total polling time.

Further, although the device is connected, when the device is not in a usable state due to power-off or the like, polling efficiency is improved by thinning out scanning by using a counter.
When the device becomes available by turning on the power supply, etc., it can be detected from the response when polled, so that the corresponding flag is turned on and the device is in the operable state. By displaying this, the normal polling cycle can be restored thereafter.

[Embodiment] FIG. 1 is a block diagram of an embodiment of the present invention, showing a configuration of a serial interface control unit of a control device, 1 is a polling control unit, 2 is a transmission / reception control unit,
3 is a flag memory, 4 and 5 are registers, 6 is an adder circuit,
Reference numeral 7 is a comparison circuit, and 8 to 13 are gate circuits.

In FIG. 1, at the time of polling, when the address of the device to be polled is first stored in the register 4, the adder circuit 6 adds "1" to generate the address of the device to be polled in ascending order. Each time, it is held in the register 4.

The address information held in the register 4 is the gate circuit 12
Alternatively, it is sent to the transmission / reception control unit 2 via the gate circuit 13 and is sent to the device to be polled by the transmission / reception control unit 2.

At this time, whether or not the address is sent to the transmission / reception control unit 2 is controlled by the gate circuit 12 and the gate circuit 13.

Hereinafter, how the gate circuit 12 and the gate circuit 13 operate will be described.

The device address held in the register 4 described above is input to the gate circuit 12 and the gate circuit 13, and is also given to the flag memory 3 so that the device address such as F1, F2, C, etc. is supplied from the address position corresponding to the address value. The information is read.

F1 is a flag indicating whether or not the device is connected (accommodated), and "1" is displayed when the device is connected, and "0" is displayed when the device is not connected.

F2 is a flag that indicates whether or not the connected device is in an operable state, and "0" is displayed when the device is not in an operable state because the device is not powered on. Has been done.

C is a counter, which is set to "0" when F2 is set to "0", the operation of which will be described later.

When the device is connected and ready to operate, both F1 and F2 are "1", so the output "1" of the gate circuit 9 causes the gate circuit 12 to open and the device Since the address value is sent to the transmission / reception control unit 2, the transmission / reception control unit 2 sends it.

When the device is not connected, F1 and F2 are mainly "0", and the gate circuits 12 and 13 are both closed. Therefore, the device address is not given to the transmission / reception control unit 2 and its transmission is not performed. Be deterred.

When the device is connected, but the device is not in an operable state, F1 is “1”, F2 is “0”, and the gate circuit 10
Output becomes "1".

In this state, if the output of the comparison circuit 7 is "1", the gate circuit
Since the output of 11 becomes "1" and the gate circuit 13 is opened, the corresponding address value is input to the transmission / reception control unit 2 and is transmitted to the outside by the transmission / reception control unit 2. If the comparison circuit 7
If the output of is "0", sending is suppressed.

The comparison circuit 7 compares the count value of the counter C in the flag memory 3 with the value held in the register 5. As a result, if the count value of the counter C is larger, "1" is output, and if it is smaller, "0" is output. While the count value of the counter C is smaller than the value of the register 5, it is updated by incrementing by one. Further, when the count value of the counter C becomes larger than the value of the register 5 and the address is transmitted,
The counter C is reset.

The polling control unit 1 sets the value of the register 5 and F1 in the flag memory 3 at the time of initial setting or at any time according to instruction information from the outside.

The transmission / reception control unit 2 determines whether or not the device is in an operable state based on the response from the polled device, and controls the display of F2 in the flag memory 3.

[Effect of the Invention] As described above, according to the method of the present invention, transmission of an address to a device not connected is suppressed, and
For devices that are connected but not currently in operation, the address is sent out with a low frequency, so that efficient polling can be performed.

Then, when the device becomes operable, which was not possible until now due to the power-on of the device,
After detecting this, there is an advantage that the control for returning to the normal polling cycle can be easily performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a configuration of a serial interface control unit of a conventional control device. 1 ... Polling control unit, 2 ... Transmission / reception control unit, 3 ...
Flag memory 4, 5, ... Register, 6 ... Adder circuit,
7 ... Comparison circuit, 8-13 ... Gate circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-132256 (JP, A) JP-A-53-50627 (JP, A) JP-A-58-139229 (JP, A)

Claims (1)

[Claims] 1. A serial interface control device for transmitting / receiving a signal to / from a specific device by sequentially sending an address to the plurality of devices, wherein each address is assigned to the plurality of devices. Correspondingly, a first flag indicating the connection state with the serial interface control device, a second flag indicating the operating state of the plurality of devices, and a counter for address transmission control are provided and at the time of address transmission. , A means for suppressing the address transmission when both the first and second flags corresponding to the address to be transmitted are off, and the first flag corresponding to the address to be transmitted is on, and the second flag Means for suppressing address transmission until the counter counts a predetermined value when the flag is turned off. Interface control device.