JPS6345820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an error detection and recovery circuit, and particularly to an error detection circuit for an endoscope light source device.

In an endoscope system, data and control signals are exchanged within a light source device and between the light source device and an endoscope camera through communication, and various operations are executed. If an electric scalpel device or the like is used to transmit and receive such data and control signals, the data communication will be disrupted and the data and control signals will not be transmitted and received correctly. Therefore, it is necessary to perform error detection and error recovery. In error recovery, it is desirable to perform error recovery immediately when there are no longer any elements that disturb communication. Therefore, since communication is not possible when the electric scalpel device is in operation, both the light source device and the camera are operated in A mode (mode that does not use communication), and immediately after the electric scalpel device is stopped, they are switched to B mode (communication mode). (mode that does not use)
It is possible that it will be reinstated. Therefore, it is necessary to constantly perform so-called error processing such as error detection and recovery. However, if process detection and recovery processes are being performed all the time, other tasks (for example, illumination light control of a light source device, air pump control,
panel display control) is forced to wait or is delayed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an error detection and recovery circuit for an endoscope light source device that quickly performs error recovery and does not impose execution time constraints on processes other than error recovery processing. .

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a block circuit of a communication system of an endoscope system. According to this diagram, endoscope 1
For example, a still camera 13 is attached to the first eyepiece via an adapter 12. Also, adapter 1
For example, a video camera 14 is attached to 2.
A universal cord 11a of the endoscope 11 is coupled to the light source device 15.

The light source device 15 is provided with a host computer (HOST) 16 and a communication interface unit (CIU) 17. HOST 16 and CIU 17 are connected by data bus 18 and signal lines 3, 3,
Connected by STATUS. camera 13
and 14 are provided with circuits 19 and 20, respectively, which incorporate a HOST and a CIU into one chip.

In the endoscope system, communication is performed between the light source device 15 and the cameras 13 and 14. In this case, the light source device 15 becomes the master station, and the camera 13,
14 is a slave station. HOST16 of light source device 15
When communicating between the CIU 17 and the CIU 17, data is assembled according to the format shown in FIG. According to this data format, the destination address, self address, data length, and text data are composed of N+3 bytes, and sum check data SMD is added after this data string. The sum check data SMD is composed of the two's complement of the addition result (1 byte) obtained by adding N+3 bytes from the beginning to the end of the data string, ignoring carry, and becomes the N+4th byte data.

A thumb check is performed when communication is performed between the HOST 16 of the light source device 15 and the CIU 17. In this case, as shown in the flowchart of FIG. 3, when the CIU detects a thumb check error, the sequence 1 to 4 is performed. An error detection and recovery mode is therefore implemented. On the other hand, HOST
1 → 3 → 4 when detects a thumb check error
The error detection and recovery mode is executed according to the order of .

In error detection, all data strings (N+4 bytes) including the SMD shown in Figure 2 are added, and if the addition result is 0, there is no error (normal).
If it is not 0, it is determined that an error has occurred. As shown in the flowchart of FIG. 3, when the CIU detects an error, the CIU 17 requests the HOST 16 to resend data. When the HOST receives a retransmission request, it resets the CIU 17. A method for resetting this CIU 17 will be described later. CIU17
When the HOST 16 is reset, the HOST 16 retransmits the data. On the other hand, if HOST16 detects an error,
HOST 16 immediately resets CIU 17 and retransmits the data.

Next, we will discuss how to reset the CIU.
Resetting the CIU is performed by hardware as shown in Figure 4. According to FIG. 4, the output of the reset circuit 21 for the entire system is the CPU 22 and
Connected to the reset terminal of PPI (parallel port interface) 23 and R. CPU22
and PPI 23 are connected by a data bus 24, and the output of PPI 23 is connected to the reset terminal of CIU 17.

In the circuit shown in FIG. 4, when the CPU 22 is reset by the reset circuit 21, the CPU 22 is reset.
data bus 24 while executing the program.
and resets the CIU 17 via the PPI 23.
That is, the CIU 17 is reset by the CPU 22 independently of the reset timing of the reset circuit 21. Also, when an error occurs, the CPU
The CIU 17 is reset according to the execution of the program No. 22.

FIG. 5 shows a time chart showing the reset timing. According to this time chart, when the power is turned on, CPU22 and PPI
23 is reset and the initial setting time t of the CPU 22
is set. a and b in CIU1
7 indicates a state arbitrarily reset by the CPU 22.

In FIG. 1, when noise is mixed into the data during communication between the HOST 16 and the CIU 17 and errors are continuously detected by thumb check, the CIU 17 is immediately reset a predetermined number of times, for example four times, and then Thereafter, it is intermittently reset at intervals of a predetermined period of time, for example, one second, until the error disappears. This reset control
This is done by HOST16. In this way, the system is reset several times at high speed initially, and then at regular intervals, allowing for rapid recovery from errors caused by noise caused by lightning, etc. Recovery processing from errors caused by noise continuously generated by the operation of devices can be performed without affecting the execution speed of other processing.

In FIG. 6, the above-mentioned error detection and recovery circuit is shown in hardware. According to this, data is input to the reception buffer 25;
The data No. 5 is transferred to the determination buffer 26, and an error detection circuit 27 determines whether or not there is an error in the data. This error detection circuit 27 includes STATUS and a time checking circuit 28 of OS3.
is connected, and upon receiving the information from this circuit 28, the error detection circuit 27 checks the received data for a thumb check, a time-over, the presence or absence of a re-request for the received data, and determines whether or not there is an error in the data. Note that STATUS indicates that the communication direction is changed from HOST to CIU when it is at H level, and from CIU to HOST when it is at L level. This STATUS is L for 500ms or more
If the level is reached, it is determined that an error has occurred. Also, within 20ms after the output of IS3, HOST
If OS3 is not received, it is determined that an error has occurred.
Note that IS3 and OS3 mean "sent data" and "received data", and both are exchanged depending on the communication direction.

When the error detection circuit 27 detects an error, it supplies a detection signal to the counting circuit 35 and the AND gate 29. The counting circuit 35 counts the number of times an error has occurred based on the detection signal. The counting circuit 35 inputs to the AND gate 29 a counting signal corresponding to the occurrence of four or less errors. The AND gate 29 sends the error signal of 4 times or less to the CIU reset circuit 3 via the OR gate 30.
Enter 1. This resets the CIU. When the error count value exceeds 4, the output of the counting circuit 35 is supplied to the timer 33 via the inverter 32. Timer 33 operates in response to the output of counting circuit 35 via inverter 32 and generates an output signal every second. The output signal of timer 33 energizes CIU reset circuit 31 via OR gate 30 at one second intervals. This causes the CIU to continue being reset at 1 second intervals.

If no error is detected by the error detection circuit 27, that is, if there is no error in the data, correct data is transferred to the primary data buffer 34. Counting circuit 35 is reset if there is no error.

As explained above, in the initial stage of error detection, error detection and recovery are performed at high speed, and after a predetermined time, error processing is performed at a relatively low speed until the error stops occurring, so it is effective against errors that occur instantly. Communication is restored normally at high speed, and error recovery processing is performed without interruption in the case of errors that occur continuously without affecting the execution time of other processing.

Although the embodiment has been described as error detection and recovery between the HOST and CIU of the light source device, if there is no error between the HOST and CIU, error detection and recovery between the light source device and the camera are performed in the same way.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an endoscope system equipped with an error detection and recovery circuit for an endoscope light source device according to an embodiment of the present invention, FIG. 2 is a diagram showing a data format, and FIG. 3 is a diagram showing an error detection circuit. Figure 4 is a flowchart showing the detection recovery sequence, Figure 4 is a circuit diagram of the circuit that resets the CIU, Figure 5 is a time chart showing the operation timing of the circuit in Figure 4, and Figure 6 is error detection and recovery. It is a circuit diagram of a circuit. 11...Endoscope, 12...Adapter, 13,1
4...Camera, 15...Light source device, 16...Host computer, 17...Communication interface unit.

Claims (1)

[Claims] 1. Error detection means provided in the endoscope light source device to detect data errors; error recovery means for performing error recovery in response to error detection by the error detection means; and error detection means detected by the error detection means. an error number counting means for counting the number of errors that have occurred, and when the number of errors counted by the error number counting means is less than a predetermined value, the error recovery means performs an error recovery operation immediately after the error is detected; An error detection and recovery circuit for an endoscope light source device, comprising means for performing an error recovery operation at regular intervals when the error exceeds a predetermined value.