can bus: the function 'recv' don't operate

[mattdudu]

Hi

i want use a CAN bus between my micropython and my PC, i can send a message but i can't receive my message whereas the message is acknowledge

i use the CAN 1 (Y3 and Y4) and the driver MCP2562

my program is:

Code: Select all

# main.py -- put your code here!
import pyb
from pyb import CAN
import os

file=open('motion.txt','w')

pyb.LED(1).toggle()
pyb.delay(500)
pyb.LED(1).toggle()

#prescaler=40=>50kBaud
can = CAN(1, CAN.NORMAL, extframe=False, prescaler=40, sjw=1, bs1=14, bs2=6)
can.setfilter(0,CAN.LIST16,1,(123,124,125,126))

def namelabel():
    data=b'1'
    try:
        can.send(data,12)
        pyb.LED(1).toggle()
    except:
        pyb.LED(2).toggle()

tim =pyb.Timer(4)               # crée un objet minuterie à l'aide de la minuterie 4 
tim.init(freq = 2)              # déclenche à 2Hz donc 500ms
tim.callback(lambda t:namelabel())
while True:
    try:
        (msg_id, rtr, filter_index, data) = can.recv(0)
        pyb.LED(4).on()
    except:
        pyb.LED(3).on()
    file.write('{}\n'.format(data))

When i run this program, a message with adress 12 is receive by my pc and the green LED (LED 1) switch all the 500ms
but the orange LED (LED 3) is on whereas my PC send my message with adress 123 without error so the function 'recv' don't operate

moreover when i run without the 'try' function the micropython is put in error (green LED and red LED flash quickly then the program stop)
it's the same with the restart function

i don't know where i my error, can you tall me if you want more information? can you tall me your supposition/answer?

thank you in advance