Hi,
I am currently working with two different development boards:
S32K312EVB-Q172
and
MCTPTX1AK324
I am trying to communicate with those at CAN-FD 500/5000 kbps.
To calculate the bit timings I am using the CAN Bit Timing calculation v2.1.xlsm provided by NXP.
For the S32K312 at CAN Clk 60MHz with the TJA1043TKY this is working fine.
But on the other board with the S32K324 at CAN Clk 80MHz and the TJA1044GT I always get Bus errors when I try to set the FD rate higher than 4mbps.
The TJA1044 is supposed to work up to 5mbps. What could be the problem there? I am using a short (30cm) untwisted cable to connect an IXXAT USB-to-CAN FD compact with an additional 120 Ohm resistor.
500/4000, 1000/4000 work fine, but as soon as I go up to 500/5000 or 1000/5000 FD frames result in errors.
Here is an example of a bit timing calculation that I tried (I think I tested all possible configurations)
Any suggestions?
Thanks & best regards,
grol
Hi Petr,
I have found the TDC setting (I must have been blind before...):
With this enabled and set according to the calbulator it works fine.
Thanks for your support!
Best regards,
grol
Hi,
you wrote messages sent from the IXXAT are read correctly by the controller, but registers show error during reception and IXXAT shows detected error during transmission. Can be CAN bit timing issue. Also be sure both have ISO CANFD protocol used.
For transmission on MCU side a TDC must be definitely enabled with proper TDCOFF set.
Not sure for EB but in S32DS CT this is available in FdBaudrateConfig setting
BR, Petr
Hi @PetrS,
Thanks for the quick reply.
Do you really use enhanced CAN FD timing and registers as shown in pictures?
Yes, but I also tried with normal mode settings, with the same result (works up to 4mbps).
Did you set TDC as well? Check the setting in debugger.
TDC is disabled according to the debugger.
This is an AUTOSAR project (SW. Version: 4.0.0 P14_HF01_D2406), the FlexCan is configured in Tresos, is the TDC configurable there?
What errors are detected on S32K324? Check ECR, ESR1 registers.
Here is the top part of the FlexCAN in the debugger showing some errors:
The IXXAT on the other end (there are no other nodes) reports the following:
And is configured with the same sample point:
A recommendation could be to measure TXD/RXD/CAN lines with scope to see real signals.
I don't have a scope available right now, but could probably organize one for next week or so.
Any more ideas what I could try until then?
Thanks!
Best regards,
grol
Hi,
all connected nodes should use same bitrate and sample times, so ensure that.
Do you really use enhanced CAN FD timing and registers as shown in pictures? Did you set TDC as well? Check the setting in debugger. What errors are detected on S32K324? Check ECR, ESR1 registers. A recommendation could be to measure TXD/RXD/CAN lines with scope to see real signals.
BR, Petr