8-bit MicrocontrollersのトピックRe: Force a CAN TXerr

Force a CAN TXerr

Saga — Fri, 28 Mar 2008 01:16:24 GMT

Hi to all,

I'm working in some method to verify the sned of a CAN message when an error ocurrs, the problem i have is... How can i force a TXerr in the CAN bus to test this method, this is for certification purposes...

I'm using a DZ60 uC... Thank you a lot guys...

Re: Force a CAN TXerr

Saga — Wed, 09 Apr 2008 01:50:53 GMT

Ok seems nobody knows or probably i didn't explain myself correctly...

In the MC9S08DZ60 there is a register called:

MSCAN Transmit Error Counter (CANTXERR)

What conditions could ocurr for this register to increment?

How could i force an error that would make this register increment??

Re: Force a CAN TXerr

allawtterb — Wed, 09 Apr 2008 02:42:43 GMT

I would suggest taking a look at AN2283, specifically the section on errors (Pages 24-40):

http://www.freescale.com/files/microcontrollers/doc/app_note/AN2283.pdf?fsrch=1

The document is meant for the MSCAN module used in HC08 and HC12 but I believe the error conditions are the same. To see the differences between the HC08/12 MSCAN and HCS08 MSCAN take a look at AN2717, Section 6.7(Page 17):

http://www.freescale.com/files/microcontrollers/doc/app_note/AN2717.pdf?fsrch=1&WT_TYPE=Application Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation

There are 5 conditions that can cause errors, 2 that are detected by the transmitter: A Bit Error and Acknowledgement Error. These are both described in the first document above on pages 24 and 25.

- Brett