topic Re: P2041 USB High Speed EHCI Controller Disable / Forcing only Full-Speed Connect in P-Series

P2041 USB High Speed EHCI Controller Disable / Forcing only Full-Speed Connect

fsever — Thu, 11 Mar 2021 10:48:32 GMT

Hi,

We are wondering that whether we can disable the USB High-Speed Control interface in P2041 in order to force the USB controller work in only Full-Speed or Low-Speed Mode.

24th bit (PFSC) of USBx_PORTSC register is usefull for this purpose but, in this register, there is a note that " this bit is only for debugging purposes".

Re: P2041 USB High Speed EHCI Controller Disable / Forcing only Full-Speed Connect

ufedor — Thu, 11 Mar 2021 11:42:49 GMT

The PFSC bit prevents the USB controller from declaring itself as a High-Speed and the Full-Speed link is established at a USB bus reset. So, the PFSC bit can be used for both testing and functional modes; there is no limitation to use it in debug mode only.

Re: P2041 USB High Speed EHCI Controller Disable / Forcing only Full-Speed Connect

vitaly_a — Mon, 26 Apr 2021 17:13:55 GMT

Hello,

I need to force full speed for EHCI host in u-boot. Do you know where in the driver I need to set the PFSC bit?

Thanks, -Vitaly