CCS/TMDXRM46HDK: RM46x HDK not accurate for DLC value on CAN1 reveive messageBoxes

NeilBerry_at_Parker

Expert 1995 points

Part Number: TMDXRM46HDK
Other Parts Discussed in Thread: HALCOGEN

Tool/software: Code Composer Studio

Following an example for RM46 devices [example_canIntCommunication], I was able to get a Can port receive into a messagebox. However, the DLC (Data Length Count) was not reliable. I tried creating eight message boxes for each DLC value between 1-8; but the behavior is not working.

How do I get an accurate DLC? Is there some reason my eight messagebox approach is not valid?

over 6 years ago

0 QJ Wang over 6 years ago

TI__Guru**** 186196 points

Hello NeilBerry,

Did you check the DLC in message RAM or from the register (IFxMCTL[3:0])?

If the control bit (IFxCMD[20]) is cleared when reading the message RAM, the control bit will not be changed, the value in IFxMCTL[3:0] will not reflect the current value in message RAM.

I will do the same test tomorrow.

0 NeilBerry_at_Parker over 6 years ago in reply to QJ Wang

Expert 1995 points

So, for CAN1; I would need to check the IF1MCTL value to determine the DLC value?

There is no function created in reg_can.[h/c] or can.[h/c] which provides the DLC value of a received can frame?

You suggestion sounds very promising. I will run some tests.

0 NeilBerry_at_Parker over 6 years ago in reply to NeilBerry_at_Parker

Expert 1995 points

In the manual, it appears that my DLC would appear on IF3MCTL. I have CAN1 IF3 VIM 44 enabled for IRQ. On receive, the entire IF3MCTL value is zero.

Is there something about this that I am doing wrong?

Upon further investigation, my HalCoGen setup assigns VIM44 to phantomInterrupt, so that is not good. What HalCoGen steps do I need to enable CAN1 IF3?

0 NeilBerry_at_Parker over 6 years ago in reply to NeilBerry_at_Parker

Expert 1995 points

I am going to marks this post as solved. Your advice on where to find DLC was helpful. I have a follow-up question that I will start a new issue for.

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CCS/TMDXRM46HDK: RM46x HDK not accurate for DLC value on CAN1 reveive messageBoxes