[CanTp] Vehicle Diagnostic Communication Part 19 [Simulation 7]

Click here for back issues.
https://www.simulationroom999.com/blog/diagnostic-communication-en-back-issue/

Introduction.
Towards CAN control with python-can
CAN interface devices that python-can can work with
python-can send and receive
python-can request-side code
python-can response side code
python-can request-response results
Conclusion

Introduction.

Let’s simulate ISO-TP. series.
This time, we will talk about programming using pyton-can.

Towards CAN control with python-can

Last time, I ran the python-can modules can.player and can.logger, but I don’t feel like I controlled them, just that I got confirmation of their operation.
Currently, the only thing I can say is “I ran the included sample programs without knowing what’s in them.”

So this time, I want to write some Python code to get a feel for how it’s being controlled!

CAN interface devices that python-can can work with

Before writing Python code, let us list below the CAN interface devices that are supported by python-can.

SocketCAN
Kvaser’s CANLIB
CAN over Serial
CAN over Serial / SLCAN
IXXAT Virtual CAN Interface
PCAN Basic API
USB2CAN Interface
NI-CAN
isCAN
NEOVI Interface
Vector
CANalyst-II
SYSTEC interface

python-can supports a variety of devices.
It also supports Vector devices, so as a result, it can support the Virtual CAN Bus.
It seems to be very versatile, as it can work with other devices as well.

python-can send and receive

The following image will be used for this experiment.

Transmission and reception image,Request side,Response side,CANID 0x111,CANID 0x222

As you can see, it sends CANID 0x111, and when it receives it, it immediately replies with CANID 0x222.
It is simple, but there is a sense of control.

To get this configuration, we need to create two programs, one for the request side and one for the response side.

python-can request-side code

The code for the request side is as follows.

import can

# Bus connection
bus = can.interface.Bus(bustype='vector', channel='0', bitrate=500000)

# sent data(CANID 0x111、DLC:8、Data：01 02 03 04 05 06 07 08)
send_msg = can.Message(
	arbitration_id=0x111, 
	extended_id=1, 
	data=[0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08])
print('Send msg : %s' % send_msg)

# transmission
bus.send( send_msg )

# reception 
recv_msg = bus.recv(timeout=1)
print('Recv msg : %s' % recv_msg)

Connect to Virtual CAN Bus with bus connection, create CAN frame with Message, send with send, receive with recv.

python-can response side code

The code for the response side is as follows.

import can

# Bus connection
bus = can.interface.Bus(bustype='vector', channel='0', bitrate=500000)

# reception
while True:
	recv_msg = bus.recv(timeout=1)
	if recv_msg != None:
		print('Recv msg : %s' % recv_msg)
		break

# sent data(CANID 0x222、DLC:6、Data：0A 0B 0C 0D 0E 0F)
send_msg = can.Message(
	arbitration_id=0x222, 
	data=[0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F])
print('Send msg : %s' % send_msg)

# transmission
bus.send( send_msg )

It will wait for reception in a loop, and when received, it will create a CAN frame for transmission and send it.

python-can request-response results

The results of each execution are as follows.

Request side

Send msg : Timestamp:        0.000000   ID: 00000111 X DLC:8 01 02 03 04 05 06 07 08
Recv msg : Timestamp: 1596259123.521760 ID: 00000222 X DLC:6 0a 0b 0c 0d 0e 0f       Channel: 0

Response side

Recv msg : Timestamp: 1596259123.514021 ID: 00000111 X DLC:8 01 02 03 04 05 06 07 08 Channel: 0
Send msg : Timestamp:        0.000000   ID: 00000222 X DLC:6 0a 0b 0c 0d 0e 0f

The following are the results recorded by can.logger at the same time.

Begin Triggerblock 
 0.000000 Start of measurement
 0.000000 1  111x            Rx   d 8 01 02 03 04 05 06 07 08
 0.001450 1  222x            Rx   d 6 0A 0B 0C 0D 0E 0F
End TriggerBlock

I feel like I have it under control perfectly.
Glad it’s working fine!!!