|Targeted Hardware||phyBOARD-Zeta (i.MX7)|
The serial console is essential for communication with and development of your design. This how-to guide will demonstrate the steps required to change the default serial debug console configuration.
Specifically, the phyBOARD-Zeta uses UART5 as the default serial console. This requires a breakout cable assembly to expose the RS-232 pins that are available on a pin header on the Zeta board, a null modem cable, and finally a serial cable to the host. The PEB-EVAL-02 board exposes UART1 via RS-232 on a DB9 connector. This will be the target configuration that the how-to guide will demonstrate.
To change the serial console for u-boot, you'll need to modify the CONFIG_CONS_INDEX and CONFIG_MXC_UART_BASE definitions in the u-boot source.
Change CONFIG_CONS_INDEX to indicate the index of the UART that is desired. In this case, we will change it from 5 to 1:
Change CONFIG_MXC_UART_BASE to indicate the UART base address of the UART that is desired. In this case, we will change it from 5 to 1:
Verify the desired UART pins are muxed correctly in u-boot:
Change the SERIAL_CONSOLE to indicate the desired 'ttymxc' device in the imx7d_phyboard_zeta_001 machine configuration. In this case, we will change it from a 4 to a 0:
In Linux the devices are zero indexed. For example, UART1 corresponds to ttymxc0 and UART5 corresponds to ttymxc4.
You'll also want to verify the desired UART pins are muxed in your device tree: