UART Q&A

Q1: Why is UART not working normally?

1. Confirm the pin used by the hardware

   

2. Confirm whether the padmux of the pin is set correctly

   Find Pad_Name in xxx_HW CheckList_xxxx.xlsx, the first line is reg and bit, the mark in the figure is the value that needs to be set.

   

3. Whether the value of reg matches

   If not, please confirm the following:

   1. Confirm the /dev/ttySx used by uart pin

      The serialx corresponds to /dev/ttySx, confirm it by checking dts.

      

   2. Confirm whether the corresponding pin is used for other purposes in pioneer3-xxx-padmux.dtsi.

   3. Confirm whether the Uart controller inside the chip matches the corresponding padmux

      0x101e 0x53(16bit) (It has been set in the rom code)

      

Q2: Can uart support the baud rate of 1.5M or 3M?

Yes, but the kernel needs to be modified as follows:

1. Add or modify tolerance = <3> in the dts node of uart that needs to be used; such as

   

2. Modify the "kernel/drivers/sstar/serial/ms_uart.c" file and change the 115200*14 in the "ms_uart_set_termios" function to 115200*30.