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Unexpected USB wake-up from hibernate

Question asked by jeremie on Mar 16, 2012
Latest reply on Mar 23, 2012 by jeremie

Hi,

 

Can you help me: I have unexpected hibernate wake-up due to USB. Thanks!

 

My configuration:

-BF548.0.2

-custom board; the USB HW part is a copy-paste from the EZKIT

-USB Type B (peripheral)

 

My problem: the core  wakes up (for USB reason: I check PLL_STAT bits) while no USB is plugged.

 

Different tries:

 

A) During hibernate, the 24MHz is kept on; before entering hibernate, CSR_HBR (APHY2) is set. After about 0.5s of hibernate, the core wakes up for USB reason.

 

B) During hibernate, the 24MHz is OFF; before entering hibernate, CSR_HBR (APHY2) is set. After about 0.5s of hibernate, the core wakes up for USB reason.

 

C) During hibernate, the 24MHz is OFF; before entering hibernate, CSR_HBR (APHY2) is NOT set. After about 1s of hibernate, the core wakes up for USB reason.

 

***** BUT *****

 

D) During hibernate, the 24MHz is kept on; before entering hibernate, CSR_HBR (APHY2) is NOT set. The core does not wake-up. The problem is the extra power consumption due to the 24MHz, which I want to avoid.

 

E) In situation A and C (I have not tried for B), if I put 100k external pull-down resistors on D+ and D-, the core does not wake-up. The problem is that it is not specified any need of such pull-down (and which value), so this is not satisfying as is.

 

 

 

Thanks for your help!

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