I wanted to use uart_c with hardware flow control. I see that GPIO header (J4) pin 15 and 16 is directly exposed as uart_c RX and TX respectively.
I dont see uart_c CTS and RTS are exposed directly on GPIO header. But looks like pin 35 and 37 are multifunction pins and can be programmed to use as uart_c CTS and RTS respectively.
If this understanding is correct, Can you please help me on how to program GPIO header pin 35 and 37 as uart_c CTS and RTS?
Hello and welcome, please join the existing topic to discuss, instead of having redundant topics thank you
I have gone through suggested topic and feels that concerns are different. And hence created new topic.
I am able to activate uart_c and could able to use pin 15 (Rx) and pin 16 (Tx) for uart_c. But because of lack of flow control pins, observing data lose on higher baudrate.
I am looking for the ways to program pin 35 and 37 on GPIO Header for CTS and RTS. Can you please help in this regards?
In that case I shall not interfere,
but regarding your problem, I am sorry as my knowledge does not extend there yet, but I am sure that, contacting khadas staff might help you,
You can follow this documentation to add your own device tree overlay to enable UARC_C hardware flow control.
- Create your own device tree overlay file:
root@Khadas:~# cat uart3-hw.dts
target = <&pinctrl_periphs>;
status = "okay";
groups = "uart_tx_c",
function = "uart_c";
target = <&uart_C>;
status = "okay";
pinctrl-0 = <&c_uart_pins>;
root@Khadas:~# dtc -I dts -O dtb -o uart3-hw.dtbo uart3-hw.dts
- Copy dtbo to
root@Khadas:~# cp uart3-hw.dtbo /boot/dtb/overlays/kvim3l
/boot/env.txt file to setup
overlays=uart3-hw i2c3 os08a10
Note: You need to remove
- Save the file and reboot the board.
I haven’t tested uart hardware flow control, please let me know whether it works for you.
I was trying with android image and building from source. So I have tried updating dts file to configure uart_c with CTS/RTS as you suggested.
I could enable flow control for uart_c and dont see data lose with higher baudrate.
Thanks for your help and suggestion.