i.MX ProcessorsのトピックRe: HOW CAN MAKE GPIO TOGGLE FASTER?

HOW CAN MAKE GPIO TOGGLE FASTER?

JHY — Mon, 13 Oct 2014 08:57:14 GMT

I use i.MX6DL with linux 3.0.35 and run GPIO toggle only.

From above tests, GPIO toggle is measured only 50KHz.

It is too slow, I think, so do I miss anything?

igorpadykov — Mon, 13 Oct 2014 09:47:56 GMT

Hi JHY

in general Linux is not real time system, it can have

large delays. In particular one can look at context switching

delays:

Probably you can write assembler subrouite for GPIOs or use

realtime OS like QNX.

Best regards

igor

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lategoodbye — Mon, 13 Oct 2014 11:55:18 GMT

Hi JHY,

please describe more in detail how you toggle the GPIOs (user space, kernel space).

Why do you need such high frequencies? For SPI or I2C?

Best regards

Stefan

JHY — Wed, 15 Oct 2014 00:56:33 GMT

How can I find references of assembler subrutines? Using that, is it possible to generate about 300KHz in linux?

igorpadykov — Wed, 15 Oct 2014 03:42:07 GMT

one can find assembler examples in folder

uboot/cpu/arm_cortexa8

it is not possible to answer if it will generate about 300KHz in linux,

since this depends on board configuration. Only running test on real board

can answer on that.

lategoodbye — Wed, 15 Oct 2014 06:47:49 GMT

By the way there is also another way from userspace: http://chiragnagpal.com/examples.html