topic Re: MSCAN on the HCS12 in S12 / MagniV Microcontrollers

MSCAN on the HCS12

metboy — Tue, 16 May 2006 18:11:02 GMT

Hi,

I've just used the Software in the App Note AN3034 to program the MSCAN. I've changed nothing in the software, but only deactivated loop back self test mode ( in CANCTL1 ).

But in the CAN0SendFrame() the Transmission completes never. The Code execution freezes hier:

CAN0TFLG = txbuffer; // Start transmission

while ( (CAN0TFLG & txbuffer) != txbuffer);
// Wait for Transmission completion

I have no idea why!

i'll be thankful for your help!

Re: MSCAN on the HCS12

Steve — Tue, 16 May 2006 19:11:00 GMT

metboy,

The CAN bus requres that nodes acknowledge messages. This happens automatically, but you need at least two nodes on the bus otherwise it will never complete a transmission.

Re: MSCAN on the HCS12

metboy — Tue, 16 May 2006 21:31:15 GMT

Thanks Steve,

for my purpuse, i have to use only one node at this time. can i send the acknowledge myself?

Re: MSCAN on the HCS12

Steve — Tue, 16 May 2006 22:06:32 GMT

You need a receiving CAN node so you either need to create a network or use loopback mode.

Re: MSCAN on the HCS12

imajeff — Tue, 16 May 2006 22:28:17 GMT

At least in my HC12 there is a LOOP bit I can set for testing, letting me send messages to myself.