TMS320F280039C: mcan_ex9_transmit cannot work normally

Yale Li 李耀先 said:

For this routine, CANFD can transmit only if clear BRS to 0

Could you give more information regarding this? (what is the data bit rate? What values are fed to the MCAN_DBTP register?)

The examples have been tested and verified regularly so there should not be any issues to run them out-of-the-box.

Given the fact, that the example only seems to be working with Bit Rate Switch disabled, there seems to be an issue with the data bit rate configuration. Please check the same in your setup.

Thanks.

Hi Sahil,

The customer has confirmed that the baud rate setting in the data field has not been modified, which is 1Mbps in the routine.

In addition, the customer wants to confirm that according to the calculation formula of sampling points (1+TimeSeg1)/ (1+TimerSeg1+TimerSeg2), the sampling points of TI products are only 55%? However, according to the relevant CAN standards, when the baud rate is 500kbps, the sampling point is recommended to be 87.5%. So the customer wants to confirm how the sampling point of TI is calculated.

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Thanks & Regards

Yale

Yale, 

Yale Li 李耀先 said:

the baud rate setting in the data field has not been modified, which is 1Mbps in the routine.

As I mentioned before, at the default settings, communication has been tested, so this will need further looking into.

Is it possible for the customer to check with an oscilloscope (preferably one that can decode CAN frames) the readings on the transmit pin, if the frame is as expected?

Yale Li 李耀先 said:

However, according to the relevant CAN standards, when the baud rate is 500kbps, the sampling point is recommended to be 87.5%.

I will look into it and get back to you on that.

Yale Li 李耀先 said:

So the customer wants to confirm how the sampling point of TI is calculated.

All timing related parameters are calculated by a spreadsheet that has been provided in the C2000ware package: C2000Ware_X_XX_00_00\device_support\f28003x\docs\MCAN_BitTimingCalculator

Thanks.

Sahil,

The following is the data waveform of MCAN_ex9_transmit when sending. At this time, the program waits at "while(HWREG(MCANA_DRIVER_BASE + MCAN_TXBTO) == 0x00000000)".

If the BRS bit is set to zero during initialization, it can be sent normally, and the waveform is as follows:

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Thanks

Yale

Yale. 

Apologies for the late reply. 

Yale Li 李耀先 said:

The following is the data waveform of MCAN_ex9_transmit when sending. At this time, the program waits at "while(HWREG(MCANA_DRIVER_BASE + MCAN_TXBTO) == 0x00000000)".

Could you mention some details about the setup you are using to receive the frame. It is likely that the device is not receiving any ACK for the transmitted frames. Can you also check the MCAN_ECR Register for the Transmit Error Counter. 

Yale Li 李耀先 said:

If the BRS bit is set to zero during initialization, it can be sent normally, and the waveform is as follows:

Is the program exiting the while loop which is what getting stuck in above?

Thanks.

Sahil,

I just got the response from the customer.

Here is the value of MCAN register when program is waiting on “while(HWREG(MCANA_DRIVER_BASE + MCAN_TXBTO) == 0x00000000)”:

And could you please take a look of this issue:

Yale Li 李耀先 said:

However, according to the relevant CAN standards, when the baud rate is 500kbps, the sampling point is recommended to be 87.5%.

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Thanks

Yale

Yale, 

We are looking into it and will get back to you soon.

Thanks.

Yale,

This should have been asked earlier, but can you check with the customer if the "mcan_ex4_receive" example working properly? I want to check if the transceiver is operating as expected.

Thanks.

Sahil,

"mcan_ex4_receive" example working properly, it can receive, including receive the message of CAN, CAN FD and CAN FD accelerate mode.

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Thanks & Regards

Yale

Sahil,

May I ask the progress of this thread?

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Thanks & Regards

Yale

Yale, 

I have assigned this thread to another expert. Please expect a response soon.

Thanks.

Yale,

    I will try this on my setup. Please give me a day or two.

Yale,

    I am seeing the same behavior with this testcase. Let me examine the pins with a scope and get back to you. Will respond before the weekend.

Hi Hareesh,

Sorry for this late reply. Some other things cause this reply delayed.

My customer use LAUNCHXL-F280039C. They modified the IO pin. Because the pin that demo ex9 used is not matched with LaunchPad.

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Thanks & Regards

Yale

+++adding information+++

Hi Hareesh,

Sorry, allow me to clarify, this issue has not been resolved.

The customer still cannot use ex9 to transmit message. Does this demo need to modify the code or board? Or can you successfully operate this demo on F280039C LaunchPad and show the steps to customer?

Very appreciate your help!

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Best Regards,

Yale

Yale,

   Let me try this on my setup. 

Yale,

    I have not been able to try this experiment yet, but will do so before early next week.