Accessibility of GPT1_COMPARE1 on the MX RT1050 - EVKB board

[strnadel]

Hello,

I have tried to use the MX RT1050 - EVKB board to reconstruct the experiment presented in https://www.nxp.com/docs/en/application-note/AN12078.pdf (Measuring Interrupt Latency), but I am unable to find where can I attach my oscilloscope in order to observe the GPT1_COMPARE1 signal.

Can you help me with that?

I have identified that GPT1_COMPARE1 (Port) belongs to GPIO_EMC_35 (Pad) and function GPIO3.IO[21] situated in E5 of device's ball map. The problem is that I am unable to identify this line physically on the board.

[strnadel]

Hello,

sending my project will not help to solve my problem - I need to know where can I attach my oscilloscope in order to observe the signal on GPT1_COMPARE1 pad of the MIMXRT1050-EVKB board. It is a pity that the authors of  AN12087 (Measuring Interrupt Latency, https://www.nxp.com/docs/en/application-note/AN12078.pdf) have not included this information in their document. I have studied more technical documentation to the board (Gerber files etc.) and it seems that the GPT1_COMPARE1 signal could be observable at the top pin of the C13 resistor situated at the bottom of the board, below the i.MX. Could you check it please? It may happen I am wrong.

Thanks,

Josef

[kerryzhou]

Hi @strnadel 

  GPIO_EMC_35 as GPT_COMPARE1, on the MIMXRT1050-EVKB, this pin is really didn't fanout, so the hardware test point is really a problem, as the RT and the SDRAM are all the BGA package.

In fact, all the GPT1_COMPARE1, GPT1_COMPARE2, GPT1_COMPARE3 no directly test point for your oscilloscope .

You can consider to use the GPT2, that COMPARE pin is fan out.

Best Regards,

kerry

[strnadel]

Hello,

I am sorry - I was unavailable for a while.

OK -  I will try the solution using GPT2 - can you help me to identify a test point for a GPT2_COMPAREx on the MX RT1050 - EVKB board ? In my opinion, it is best to use GPT2_COMPARE3 (GPIO_AD_B0_08) - it should be available via the test point TP11 if I am right. Can you help me to localize TP11 on the MX RT1050 - EVKB board, please ?

Thanks a lot.

[kerryzhou · Accepted solution]

Hi @strnadel ,

   About the GPT2_COMPAREx pins can be found as follows:

In the MIMXRT1050-EVKB rev A1, the related point is:

You can find, it is the JTAG/SWD related pins.

You can use  GPT2_COMPARE3 (GPIO_AD_B0_08), it is TP11, but please note, when do the testing, make sure, when enter the debug mode, it is pull down, otherwise, the debug will be influenced.

Wish it helps you!

BTW, as this case is a little old, if you have any new updated information, it's better to create the new question post and let me know. To one case, it can't open too long time, thanks a lot for your understanding.

Best Regards,

kerry

[jvmreis]

I programmed a code using the MX RT1050-EVKB board that can test the AN12078 application note and can be accessed on my GitHub: Interrupt_lesson
It is a public repository that I created for educational purposes, feel free to use and suggest improvements.
The repository consists of 2 projects. One uses bare metal and the other uses Freertos. With these codes it is possible to compare the interruption time results obtained in the practical tests with the results of the application note.

[kerryzhou]

Hi @strnadel ,

   From the RM, we can know the GPT1_COMPARE1 pin:

So, in the project pinmux.c, you need to configure the GPIO_EMC_35 as GPT_COMPARE1 function.

Then, you need to write the GPT code, and make the compare function works, then output to the compare1 pin.

more details, please check RM Chapter 51 General Purpose Timer (GPT).

Wish it helps you！

Best Regards,

Kerry

[strnadel]

Hello,

thanks for you answer, but that's what I have already programmed before and what already works.

But, the problem I have relates to measuring/monitoring the GPT1_COMPARE1 pin, e.g., using an oscilloscope - I am unsure where (on the MX RT1050 - EVKB board) I can attach/connect the probe of my oscilloscope in order to monitor the pin. Can you help me to identify/localize such a measurement/monitoring place on the MX RT1050 - EVKB board?

Thanks for your time and help.

Josef

[kerryzhou]

Hi @strnadel ,

  Please upload your testing project.

  And also tell me your test point on the MIMXRT1050-EVKB, I need to help you to check it at first.

Best Regards,

kerry