MQX FlexCAN FIFO message reception delay

[mpfgregory]

I'm using the MQX FlexCAN FIFO receive mechanism. It works fine except for a delay in message reception. When the first CAN message is received, the output of the FIFO is a message containing only zeroes. The same happens for messages 2-5. When the 6th CAN message is received, the output of the FIFO is the first CAN message that was received. It continues like this. The 7th message received brings the 2nd message to the FIFO output and so on.

Is this intended behavior? I know the FIFO is 6 message buffers deep.

I'm using MQX 4.0 with the Phytec patches for the PCM052. This version didn't contain the FlexCAN driver. A while back I integrated the FlexCAN Driver from MQX4.1 into it. I see this behavior with the FlexCAN example application.

[jjt]

FWIW, the same bug is STILL present in MQX5 FlexCAN driver for K60. 

[CommunityBot · Accepted solution]

This an automatic process.

We are marking this post as solved, due to the either low activity or any reply marked as correct.

If you have additional questions, please create a new post and reference to this closed post.

NXP Community!

[karina_valencia]

rendy​ do you have an update?

[rendy]

Hello, yes this is known design flaw. However there is no plan for this to be patched.

[mpfgregory]

Hello Rene,

thanks for the answer. Is this a design flaw in the MQX driver, or is it a flaw of the CAN module on the Vybrid? If it's just the driver I would try to fix it. Else the FIFO is not useful for our application because we need the data in real time.

[rendy]

Hi,

it's a software issue. Hardware works well.

Regards

Rene