topic Re: Is it possible to transfer high speed data via HSGPIO using eDMA? in i.MX RT Crossover MCUs

Is it possible to transfer high speed data via HSGPIO using eDMA?

OMG — Mon, 29 Jul 2024 16:17:42 GMT

Hello everyone!

I am new in NXP products and while using I have the following problem:

I need to output data at a frequency of 150 MHz to an external device. As a data bus, I chose to use one of the two ports of the high-speed GPIO CM7_GPIOn.
Research showed that at the core frequency(996MHz), with maximum compiler optimization, with the port pins toggled in the cycle:
CM7_GPIO3->DR_TOGGLE = 0xFFFFFFFF;
I got a frequency of ~250 MHz.

When trying to use DMA, data transfer did not work - the channel bit is set in the ERR register, which means a transfer error. At the same time, with a regular GPIO3 everything worked out, but the transfer frequency is of course much lower than necessary.

Please tell me what I could have done wrong and is it even possible to implement what I have planned?

Thanks in advance

Re: Is it possible to transfer high speed data via HSGPIO using eDMA?

Pablo_Ramos — Thu, 08 Aug 2024 22:20:01 GMT

Hi @OMG,

Thanks for reaching out.

As we are discussing in your other support ticket, we still investigating this issue and I will get back at you as soon as possible in the ticket.

Re: Is it possible to transfer high speed data via HSGPIO using eDMA?

OMG — Tue, 13 Aug 2024 07:27:40 GMT

I got an update from NXP support on this issue - the answer was that DMA does not have access to HS GPIO, thanks to Pablo for the answer!
Since this option cannot be used here, I have the following questions:
- What are HS GPIOs for anyway and what are their possible use cases?
- Is there any way to transfer data in pure form over a parallel bus with a frequency of <=150MHz?

Thank you in advance

Re: Is it possible to transfer high speed data via HSGPIO using eDMA?

nickwallis — Tue, 13 Aug 2024 17:22:41 GMT

@OMG you might consider using the SEMC interface, I think for RT117x it can be clocked at up to 200MHz and can be 16-bits wide in SRAM mode.

Re: Is it possible to transfer high speed data via HSGPIO using eDMA?

Pablo_Ramos — Fri, 16 Aug 2024 23:15:23 GMT

Hi @OMG,

As @nickwallis mention you can take a look to SEMC and FlexIO or FlexSPI