Other NXP ProductsのトピックTLC5973 interface with iMX8MP

TLC5973 interface with iMX8MP

bgaurav1718 — Fri, 16 Aug 2024 07:39:37 GMT

Hello.
I need to interface iMX8MP with TLC5973 for controlling RGB led. I am planning to use libgpiod library to bit-bang the gpio. But I am really skeptical regarding obtaining the desired minimum frequency of 300kHz. Since libgpiod is a user-space library, numerous layers of delays may be involved in between. One alternative I can think of is kernel-space driver but again, handling the task-preemption might be next issue.

Here is a snapshot from TLC5973's datasheet where the information regarding frequency is provided. You may refer to the attached datasheet for further information.

Also, here is a post about the frequency limitation of libgpiod:

I am looking for suggestions that I can implement to obtain the desired frequency. Also, if it is not possible, what are my possible alternatives to control RGB led through a single gpio pin?

TLC5973 datasheet

RGB Led Datasheet

Re: TLC5973 interface with iMX8MP

joanxie — Mon, 19 Aug 2024 02:11:27 GMT

how do you connect TLC5973 with imx8mp, and how do you set the frequency? is your code is based on nxp source code? or just a standalone gpio sample code to control TLC5973? you demands is that gpio of imx8mp can be set to 300khz?

Re: TLC5973 interface with iMX8MP

bgaurav1718 — Mon, 19 Aug 2024 04:11:09 GMT

The SDI pin of TLC is connected to one of the gpio pins.
Regrading frequency, the datasheet mentions the range between 100kHz and 3000kHz. I tried using libgpiod library but the frequency is too low.
Yes, if I can set the frequency of gpio around 300kHz, I think I can communicate with the TLC effectively.

Re: TLC5973 interface with iMX8MP

joanxie — Fri, 23 Aug 2024 03:29:22 GMT

I missed the code you post here for the libgpiod, after you tried libgpiod（even change the code for (int i = 0; i < 20000; ++i)）, what frequency do you get? what do you mean too slow?