MSCAN on the HCS12

[metboy]

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!

[Steve]

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.

[metboy]

Thanks Steve,

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

[imajeff]

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

[Steve]

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