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Re: connecting pyboard to CAN BUS
Posted: Fri Sep 02, 2016 5:36 pm
by dhylands
I would find such a shield useful, but I'd prefer to see a separate output for each port, and perhaps have the option of connecting them together using jumpers.
Re: connecting pyboard to CAN BUS
Posted: Fri Sep 02, 2016 9:40 pm
by kamikaze
dhylands wrote:I would find such a shield useful, but I'd prefer to see a separate output for each port, and perhaps have the option of connecting them together using jumpers.
the only reason there would be separate outputs needed - if you want to join separate CAN buses... otherwise single output is the same as two separate - in the end they will be connected to the same two wires of the CAN bus
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 2:01 am
by kamikaze
no... even with transceivers it doesn't work and fails in the same way
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 3:19 am
by PappaPeppar
How do you wire your P1 to the pyboard connectors. Have you measured whats on the pins of the transceivers?
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 3:27 am
by PappaPeppar
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 2:35 pm
by kamikaze
PappaPeppar wrote:How do you wire your P1 to the pyboard connectors. Have you measured whats on the pins of the transceivers?
I have updated scheme image, added PyBoard pins onto P1
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 3:03 pm
by kamikaze
could you please provide the code which you test this skin with?
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 3:15 pm
by kamikaze
after 3 send() calls I'm getting OSError 16. So it looks like all 3 TX mailboxes are filled and nothing being sent to the bus/receiver.
Then I've connected my DSO Quad oscilloscope to CAN2 TX and GND, and captured folloring stuff:
the code was:
Code: Select all
def cb1(bus, reason):
print('cb1', bus, reason)
def cb2(bus, reason):
print('cb2', bus, reason)
def init_cans():
can1 = CAN(1, CAN.SILENT)
can2 = CAN(2, CAN.NORMAL)
can1.setfilter(0, CAN.LIST16, 0, (123, 124, 125, 126))
can1.rxcallback(0, cb1)
can1.rxcallback(1, cb1)
can2.rxcallback(0, cb2)
can2.rxcallback(1, cb2)
return can1, can2
can1, can2 = init_cans()
can2.send('magic', 123)
Re: connecting pyboard to CAN BUS
Posted: Sat Sep 03, 2016 5:44 pm
by kamikaze
ok. my fault. Now it works. MCP2562`s Vdd should be connected to V+, while Vio to 3V3. Will fix a scheme soon ) Thank you for help
Re: connecting pyboard to CAN BUS
Posted: Sun Sep 04, 2016 2:48 am
by kamikaze
Another question. Is it fine to do bus.recv(0) in rx callback?
With following code
Code: Select all
from pyb import CAN
def cb10(bus, reason):
print('cb1_0', bus, reason)
print(bus.recv(0))
def cb11(bus, reason):
print('cb1_1', bus, reason)
print(bus.recv(1))
def cb2(bus, reason):
print('cb2', bus, reason)
def init_cans():
can1 = CAN(1, CAN.NORMAL)
can2 = CAN(2, CAN.NORMAL)
can1.setfilter(0, CAN.LIST16, 0, (123, 124, 125, 126))
can1.setfilter(1, CAN.LIST16, 1, (113, 114, 115, 116))
can1.rxcallback(0, cb10)
can1.rxcallback(1, cb11)
can2.rxcallback(0, cb2)
can2.rxcallback(1, cb2)
return can1, can2
I am getting following exception when rx callback is being executed on bus.recv():
>>> can1, can2 = init_cans()
>>> can2.send('magic', 113)
>>> cb1_1 CAN(1, CAN.NORMAL, extframe=False) 0
uncaught exception in CAN(1) rx interrupt handler
MemoryError:
and then callback stops working silently while I still can do can1.recv() and receive data manually