TMS320F28388D: The T-format encoder code stays at PM_tformat_startOperation

Thank you very much for your reply! In fact, I have provided the encoder with a stable separate power supply, and with a common ground.In addition, data from the encoder can also be measured. But the code stays in the PM_tformat_startOperation () function.

Lori Heustess said:

The CLB generates the SPI clock - is this output from the CLB routed back into the SPI?  

The clock generated by CLB is routed to the SPI module through the PWM4B port，Configurations of GPIO ports are as follows:

void tformat_setupGPIO(void)
{

    //
    // GPIO7 is SPI Clk slave
    //
    GPIO_setMasterCore(7, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_7_EPWM4B);

    //
    // GPIO16 is the SPISIMOA
    //
    GPIO_setMasterCore(16, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_16_SPIA_SIMO);
    GPIO_setQualificationMode(16, GPIO_QUAL_ASYNC);

    //
    // GPIO17 is the SPISOMIA
    //
    GPIO_setMasterCore(17, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_17_SPIA_SOMI);
    GPIO_setQualificationMode(17, GPIO_QUAL_ASYNC);

    //
    // GPIO18 is the SPICLKA
    //
    GPIO_setMasterCore(18, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_18_SPIA_CLK);
    GPIO_setQualificationMode(18, GPIO_QUAL_ASYNC);

    //
    // GPIO19 is the SPISTEA
    //
    GPIO_setMasterCore(19, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_19_SPIA_STEN);
    GPIO_setQualificationMode(19, GPIO_QUAL_ASYNC);


    //
    // GPIO15 is tformat TxEN
    //
    GPIO_setMasterCore(15, GPIO_CORE_CPU1);
    GPIO_setPinConfig(GPIO_15_OUTPUTXBAR4);

}

I can capture the clock waveform at the clock output port PWM4B (GPIO7) and GPIO18, which indicates that the SPI module can get the clock normally.

Lori，

I built a new CCS project from scratch，I directly use the probe of the logic analyzer to measure the pin of the chip (F28388D), which can measure the clock waveform, enable waveform, instructions issued by MCU, as well as the data feedback from the encoder.These all show that my MCU works well.And now the code stays in while(tformatData.dataready!= 1);/ / {}

I tried to make the encoder use a separate power and carefully common ground, but unfortunately couldn't solve the problem.

Best regards

Johnson Alanl

Lori Heustess said:

The encoder responds, but the C28x doesn't see the response.  In your first screenshot - does the clock continue toggling?  It stops so it looks like the CLB itself is not seeing the incoming response. When the first falling edge comes in on SIMO, the CLB should start clocking the SPI.   It should come through an input XBAR from the SIMO to the CLB. 

This does look like an encoder response, but C28x does not see the response.So where else do I need to change the code besides the following?

Best regards

Johnson Alanl

Lori，

Thank you very much for your reply!I think I've found the key to solving the problem, in my code I'm using the clock waveform from the PWM4 port, so I might not be able to use SPIA.Because I saw this table in the chip manual:

Please check if this means CLB4 must be used if using PWM4 port to generate waveform and then must be bound to SPID module as well.

Best regards

Johnson Alanl

Lori Heustess said:

I suspect the response to the SPI is not going to the right place or the CLB does not see it. 

Lori，How do I check for these?

Best regards

Johnson Alanl

Lori，

I have changed PWM4 to PWM1, CLB4 to CLB1, and got data on SIMO pins (as shown below), but unfortunately the code still stops at: while(tformatData.dataready!= 1);/ / {}

1. In addition, I would like to ask whether the logical configuration in the CLB system file needs to be modified, as shown below:

2.Could you please help to check the rationality of the hardware design?

Best regards

Johnson Alanl

Lori，Thank you very much for your last reply.

I checked the hardware circuits again, but I didn't find anything wrong.However, I found that no matter how I rotated the encoder axis, SPI related parameters in the register did not change. Does this mean that although I had measured the data in the pin of the chip (F28388D), these data were not mapped to the register normally?I think maybe I should check the SPI code Settings.

Best regards

Johnson Alanl

Hi Lori，

Thank you and your colleagues very much for helping me. Thank you again!

Best regards

Johnson Alanl

Hi,Lori:
I think I found the reason why the code is stuck in the while loop. By comparing the clock waveform of F280049C (F280049C has been debugged successfully) with that of F28388D,I found that F28388D received data clock number is abnormal (the normal number of received data clock should be slightly more than the number of received data bits), as shown below are F28388D received data clock and F280049C received data clock:

So, do you think the code stays in the while loop because of this problem?If I am right, how can I modify the code to meet this requirement?

Best regards

Johnson Alanl

Hi,Lori:

My encoder has successfully read the data, and I have changed the clock number.Thanks for your guidance!

Best regards

Johnson Alanl

Hi,Lori:

I carefully compared the CLB parameters and modified it, perhaps because I changed the original algorithm from the beginning.In addition, SPI and CLB also have a one-to-one correspondence, which can not be ignored.

Best regards

Johnson Alanl