MX9 UART
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DART-MX95 UART
UART Overview
UART Overview - DART-MX95
The DART-MX95 expose up to eight LPUART interfaces, some of which are multiplexed with other peripherals.
Serial Port | Device Node | Device Tree | DART-MX95 / DT8MCustomBoard |
---|---|---|---|
UART1 | /dev/ttyLP0 | lpuart1 | DT8MCustomboard serial console |
UART2 | /dev/ttyLP1 | lpuart2 | Disabled by default, see datasheet |
UART3 | /dev/ttyLP2 | lpuart3 | Disabled by default, used as Cortex-M7 console, connected to DT8MCustomboard J12.11 and J12.13 |
UART4 | /dev/ttyLP3 | lpuart4 | Disabled by default, see datasheet |
UART5 | /dev/ttyLP4 | lpuart5 | 1.8V Signal level, used on SOM for Bluetooth interface and can be accessible only if Bluetooth is disabled.[1] |
UART6 | /dev/ttyLP5 | lpuart6 | Disabled by default, see datasheet |
UART7 | /dev/ttyLP6 | lpuart7 | Disabled by default, see datasheet |
UART8 | /dev/ttyLP7 | lpuart8 | Connected to DT8MCustomboard J12.4 and J12.6 |
Disabling Bluetooth / Enabling UART5 (/dev/ttyLP4)
UART4/ttyLP4 is used by the Bluetooth on the SOM. To use it on the carrier, Bluetooth must be disabled on the SOM.
First, disable variscite-bt by running:
# systemctl stop variscite-bt; systemctl stop variscite-ot # systemctl disable variscite-bt; systemctl disable variscite-ot
Then, disable bluetooth in the device tree imx95-var-dart.dtsi:
&lpuart5 { ... bluetooth { compatible = "nxp,88w8987-bt"; status = "disabled"; }; ... };
Testing UART8
The following demonstrates how to test UART8 on the DART-MX95 DT8MCustomboard following the table above.
Short J12.4 and J12.6pins and run the following commands:
# stty -F /dev/ttyLP7 -echo -onlcr 115200 # cat /dev/ttyLP7 & # echo hello > /dev/ttyLP7
For each invocation of echo command the "hello" string should appear on the terminal.