Activate i.MX internal UARTs
Nothing special to do, the 2 UARTS are activated by default.
- On i.MX27 UART controllers pins are multiplexed with other peripheral controllers. So configuration is a little more difficult.
$ make linux-menuconfig
Device Drivers ---> Character devices ---> Serial drivers ---> [*] IMX serial port support [*] Console on IMX serial port -*- UART1 [ ] UART2 -*- UART3 [ ] UART4 [ ] UART5 [ ] UART6
Some UARTs will be preselected or won't be available, depending on the other devices configured or the baseboard used. (For example UART4 is not available on APF27Dev; indeed pins are used for USB1).
- Reflash your Linux kernel
Now you have activated your serial port, you can use them: Serial ports usage on Linux