Hi,

In the documentation for Rambutan it says there are "2x serial port" but in the Pinout Information there is no reference to the second UART pins.

Does anyone know how to use the second UART? (for PCB not using Dev board)

Hi gedass, thanks for the reply.

Where do I define which GPIO pins are to be the 2nd UART...so that the board knows?

Hi gedass,

Sorry can you simplify the process somewhat?

Using customised OpenWRT build pulled from 8devices GIT repo, and I have GPIOs 18 and 19 connected to a UART device. What do I need to do?

Thanks!

The following answer from 8devices shows the solution

There is 'qca_mux_ctl' utility that can configure GPIO pinmux settings. It is included in default 8devices firmware image [1].

To configure UART1 on GPIO 21/22:
1. Write attached config file to /etc/qca_mux_conf.json.
2. Run (with no arguments): 'qca_mux_ctl'
3. Write to serial port: 'echo AAAA > /dev/ttyATH0'

You can choose to use other GPIOs by changing config file. There are few examples of syntax in /usr/share/qca-mux-ctl/examples/ .

If you want to use terminal for serial port:

opkg update
opkg install picocom
picocom -b 115200 /dev/ttyATH0

[1] http://pkg.8devices.com/rambutan/v2.9/openwrt-8devices-v2.9-ar71xx-nand-rambutan-squashfs-nand-sysupgrade.tar