TMS320F28335: I have a question about ecan with TMS 28335 DSP

InGwon Jo

Part Number: TMS320F28335
Other Parts Discussed in Thread: C2000WARE

Hi.

When I use the ecan function of the 28335 dsp, I need to use 32 mailboxes, but if the mailbox number exceeds 16, the rx function stops working.

When I checked the manual, it was confirmed that if ECanaShadow.CANMC.bit.SCB is set to 1, it is set to eCAN mode and all 32 mailboxes can be used.

When mailbox 0~15 is used, mailbox0 set as RX and other mailboxes also work. However, if the register is set to use mailboxes 0 to 16, rx does not work.

When it stops working, the enable signal of mailbox0 is changed to 0. (When using 0~15, it keeps 1, but if you increase mailbox to 0~16, it is automatically changed to 0. I did not change the code directly)

Except for the SCB register, I want to know if there are any other registers that limit the number of mailboxes. If not, I'd appreciate it if you could let me know what might be causing this to happen.

This is a very urgent question, so I would be very grateful if you could give me a quick answer.

over 4 years ago

0 Joseph Casuga over 4 years ago

TI__Mastermind 38730 points

Hi InGwon,

Sorry, one basic question - do you have a different function for initializing the CAN module or are you using the CAN initialization function in C2000Ware? Reason I am asking is that the CAN initialization in C2000Ware sets up the module in eCAN mode. By default, SCC mode is the default. Just making sure this was taken care of in your CAN initialization function.

Regards,

Joseph

0 InGwon Jo over 4 years ago in reply to Joseph Casuga

Prodigy 90 points

I use CAN initialization function in C2000Ware.

0 Joseph Casuga over 4 years ago in reply to InGwon Jo

TI__Mastermind 38730 points

Can you monitor the state of the SCB bit before assigning mailbox 0-16 as RX objects and immediately after configuring mailbox 0-16 as RX objects? It is unusual that the module goes into SCC mode just by assigning the mailboxes. Clearing the SCB bit is the only method to switch from eCAN to SCC. Maybe part of the code is writing to the CANMC register inadvertently?

0 InGwon Jo over 4 years ago in reply to Joseph Casuga

Prodigy 90 points

Writing to the CANMC register code only CAN initialization function. (search project)

0 Joseph Casuga over 4 years ago in reply to InGwon Jo

TI__Mastermind 38730 points

Did you monitor the state of the SCB bit as requested above:

"Can you monitor the state of the SCB bit before assigning mailbox 0-16 as RX objects and immediately after configuring mailbox 0-16 as RX objects?"

This may narrow down where the switch from eCAN to SCC mode is happening.

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TMS320F28335: I have a question about ecan with TMS 28335 DSP