topic UART output garbled in i.MX Processors

UART output garbled

caibai — Wed, 14 Sep 2016 13:58:31 GMT

hi，

i run FreeRTOS on cortex-M4 and linux on cortex-A9,when i run demo app <FreeRTOS_BSP_1.0.0_iMX6SX/examples/imx6sx_sdb_m4/demo_apps/low_power_imx6sx/periodic_wfi_qspi> and cortex-M4 uart garbled after linux startup,it seems that uart clock is change,what can i do?

Re: UART output garbled

caibai — Thu, 15 Sep 2016 13:31:30 GMT

i find that uart root clock will change from osc to PLL3 ,so when i get this change on cortext-M4, then reconfigure uart like

DbgConsole_Init(BOARD_DEBUG_UART_BASEADDR,80000000,115200);

but it also output garbled.

when are the clock init in linux

Re: UART output garbled

Carlos_Musich — Mon, 19 Sep 2016 21:26:42 GMT

Hi cai bai,

Sometimes there are problems in clock sync when A9 starts. Run your system and stop the bootloader, then apply the following commands and run your application.

env default -a

setenv fdt_file imx6sx-sdb-m4.dtb

setenv bootcmd "run m4boot;${bootcmd}"

setenv mmcargs "${mmcargs} uart_from_osc"

saveenv

Please let me know if it works.

Regards,
Carlos

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Re: UART output garbled

caibai — Fri, 23 Sep 2016 23:58:56 GMT

it work now ,thank you very much