LS1021A-IoT UART Problem

[tae-hyungkim]

I have a two board. One is ls1021a-twr and other is ls1021a-iot.

When I modify UART part (uart 2, 3, 4) disabled -> okey in device tree file with ls1021a-twr, I can use uart 2, 3, 4.

But I can not use uart 2, 3, 4 in ls1021a-iot board.

I can see ttyS2, ttyS3, ttyS4. I can not send signal with minicom.

UART 2, 3, 4 is duplicated with LPUART1 (RXD, TXD, RTS, CTS) and LCD H-Sync, V-Sync signal.

In ls1021a-iot document page 12 : For full VSYNC/HSYNC support, the RCW needs to be updated to enable these signals and UART1 cannot be used. See the device errata for details.

For using UART, RCW must be modifyed?

[Pavel]

It looks like that RCW should be changed on your board.

Check RCW on your board. Look at the Table 3-3 of the LS1021A Reference Manual:

https://www.nxp.com/webapp/Download?colCode=LS1021ARM&location=null&fasp=1&WT_TYPE=Reference%20Manua...

Have a great day,
Pavel Chubakov