i.MX ProcessorsのトピックRe: UART2 No Rx data with Android R10.4 worked perfectly on R9.2! What happened?

UART2 No Rx data with Android R10.4 worked perfectly on R9.2! What happened?

mbp — Sat, 11 Jan 2014 00:33:57 GMT

Updated from R9.2 to R10.4 on Mx51-BBG system. Used UART2 (ttymxc1) for serial communication to proprietary HW. Tx works fine but absolutely no Rx.

Analysis indicates that ttymxc1 is now owned by gps - where in 9.2 it was bluetooth, not sure this means diddly-squat. mx51_babbage.c file calls correct IOMUX from all I can see.

Not sure if this is a Kernel or Android issue or some service is grabbing the incoming data so my app sees nothing....

Been beating on this for several days :smileyconfused: and hope that someone out there has encountered a similar issue and could point the way.

HELP!

thanks :smileyhappy:

Re: UART2 No Rx data with Android R10.4 worked perfectly on R9.2! What happened?

mbp — Fri, 24 Jan 2014 21:30:30 GMT

Solved!

...required an iomux definition tweak in the Kernel.

Re: UART2 No Rx data with Android R10.4 worked perfectly on R9.2! What happened?

normancheung — Sat, 26 Apr 2014 21:28:02 GMT

Mike,

Could you please share what is the IOMUX tweak? I am running ito the same problem.

Thanks,

Norm

Re: UART2 No Rx data with Android R10.4 worked perfectly on R9.2! What happened?

mbp — Thu, 08 May 2014 19:07:42 GMT

Norman,

Without booting my Linux system, I believe this is the patch. LEt me know if it doesn't fix it.

In ../arch/arm/plat-mxc/include/mach/iomux-mx51.h:

- #define _MX51_PAD_UART2_TXD__UART2_TXD IOMUX_PAD(0x62c, 0x23c, 0, 0x09ec, 3, 0)

+ #define _MX51_PAD_UART2_TXD__UART2_TXD IOMUX_PAD(0x62c, 0x23c, 0, 0x0000, 0, 0)

Mike