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LPC546xx minimal clock speed when using USB1 in full speed

Question asked by Arno Moonen on Feb 20, 2019
Latest reply on Feb 21, 2019 by ZhangJennie

We are using the USB1 (high speed USB peripheral) from the LPC54606, but we are using it in Full Speed mode (which is a lower speed than high speed).

The reference manual mentions that the system clock should be at least 60 MHz for high speed USB operation, but it is unclear to me what the clock frequency should be in case of using it in Full Speed.
Currently the system is clocked at 48 MHz and our Mass Storage Class implementation (based on the example in the MCUXpresso SDK) is working without any problems.

However we are seeing some issues with the CDC ACM implementation (also based on the example from the SDK) and I'm wondering if this might have anything to do with it, or if I need to look in a different area.

 

Hopefully someone can give me some background/additional information on this speed requirement.

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