Can iMX6 PWM support 24MHz output？

[raymondwang]

my board design has a usb hub which require 24MHz crystal to drive. Can MX6 PWN support such high frequency output?

[pavelkrejsa]

Dear Raymond,

have you found solution ? I am facing the same problem, but cannot find proper answer with kernel 3.10.17.

Is there any guide, how to generate 24MHz output from the i.MX6?

Thanks for answer

Pavel

[raymondwang]

By default,we add an extra crystal for usb hub and also left an option to use MX6 OSC 24MHz output (cut in standby mode,it does not matter since usb hub also not required in standby mode).

[pavelkrejsa · Accepted solution]

Thanks for the reply. In the meantime, I managed to find sollution.

External oscillator is impossible now (maybe next revision of our HW).

Easiest solution is to set CCM_CCOSR register and pin configuration for CCM_CKO1 / 2 in bootloader.

In device tree, there is necessary to keep iomux option for CCM_CKO1 / 2 also as shown in examples for sabre platform or for wandboard.

There is also possible to do it in kernel, but requires more effort.

Hope this can help someone :smileyhappy:

Best Regards

Pavel