Hello,
My name is Leo, I work with a uController LPC2368 and I'm in a CAN bus project.
I recently bought on the Internet a CAN J1939 Simulator(Dafulai Electronics), but I can't send a message to the simulator successfully. I configured the uC to generate an interrupt every time that it sends or receives a message, but this interrupt is NEVER generated.
By the way, I'm able to make a communication in self test mode.
Reading about the CAN bus, I realize that it uses CSMA/CD technique. My doubt is, does the uController do by it self the verification on the bus before the transmission, or should I do this by software?
Waiting for a help! Thank you!
Just another question. Something that I look for, but I didnt find an answer..
What is the ERRBIT (16...20) at CAN1ICR register? I get an error in this bits
00111 - ID17..13
I dont have any idea about what this means.
Thanks.
The CAN controller listens on the bus - it automatically figures out when cable is idle. And if two starts sending at same time, one of the controllers will notice collision and stop.
The error bit notices an error on the bus - either your transmission fails to be read back, or you seem to send out into the air.
There is a counter keeping track of number of transmission errors - and after too many errors the controller deactivates itself to make sure an error in your device doesn't block the bus for other devices.
Thank you for your answer.
Do you have any idea why the interrupt is not generated when I send a message? When I use self test mode everything works fine, I transmit, receive and the interruption works ok..
And I cant even receive a message, I've programmed to just listen the bus, and I get various different errors in ERRBIT. Each time I got a different one.
But the bits 0 to 15 of CAN1ICR are every time = 0 !! I never got an transmit or receive interrupt!