AnsweredAssumed Answered

LPC546xx High sped USB compatibility

Question asked by jiashuan zou on Jul 13, 2020
Latest reply on Jul 15, 2020 by jiashuan zou

I try to use LPC546xx High speed USB1 port to connect with Lenovo T420 by ISP mode. That have chance to fail ( unknow device ). Our LPC546xx's USB1 is pass eye diagram.

The following is LPC546xx USB1 eye diagram test.


However, Lenovo T420 always can detect hard disk thought High speed USB 2.0 mass storage. By the way I also serial USB cable to High speed USB 2.0 mass storage to simulate LPC546xx's situation.


I found LPC546xx USB1's high speed detect handshake have some abnormal waveform.

The following is LPC546xx  high speed detect handshake waveform. ( Blue is D+, Yellow is D- )

 This is fail waveform.

This is retry to success detect


The following is High speed USB 2.0 mass storage with USB cable. ( Green is D+. Purple is D- )