Can we use Uart RTS signal to control RS 485 direction in half duplex mode?
We found RTS signal is not driven from Jetson module.
Which UART instance are you using? On Jetson Orin NX there are three UARTs. UART0 and UART1 support hardware flow control signals. Refer to data sheet https://developer.nvidia.com/downloads/jetson-orin-nx-module-series-data-sheet
You would also need a suitable RS232 to RS485 converter which meets your requirements.
We use SP339 for RS232/422/485 mode.
The pin103 RTS signal is used to request to send on RS232, but RS422/485 should be disabled. But we found an issue when disabling RTS and check RS422/485
UART0 > FAIL
UART1 > PASS
How should we control the RTS on UART0?
Hi andyyu,
Are you using the devkit or custom board for Orin NX?
What’s the Jetpack version in use?
It is for UART0 (uartb@3110000).
You have to enable HW flow control in your use case to get RTS working.
And also, please check if the similar configuration as RS485 Not Working After Upgrading to Jetpack 36.4 on Jetson AGX Orin with jetpack 6.1 - #6 by KevinFFF can help for your case.
Hi Kevin,
We are using Jetpack6.2 on our carrier board for Orin NX.
a. Could we configure the pin103 of RTS pin to function pin for uartb@311000?
b. What’s the mapping of UART0/1 & ttyTHS port?
w4@JSOR:~$ sudo dmesg |grep ttyTHS
[ 1.750383] 3100000.serial: ttyTHS1 at MMIO 0x3100000 (irq = 112, base_baud = 0) is a TEGRA_UART /// UARTA
[ 1.751463] 3140000.serial: ttyTHS3 at MMIO 0x3140000 (irq = 113, base_baud = 0) is a TEGRA_UART
[ 1.752295] 3110000.serial: ttyTHS2 at MMIO 0x3110000 (irq = 198, base_baud = 0) is a TEGRA_UART ///UARTB
should it be as below?
UART0 > UART B, ttyTHS2
UART1 > UART A, ttyTHS1
Yes, this pin is used as RTS for UART-B, you can find it as following:
From the dmesg you shared, it is correct.
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