Jetpack: JP6.0 （R36.3）
1. Hardware Connection
2. Device Tree Configuration
serial@3130000 {
resets = <0x03 0x67>;
interrupts = <0x00 0x73 0x04>;
clocks = <0x03 0x9e>;
compatible = "nvidia,tegra194-hsuart";
status = "okay";
reg = <0x00 0x3130000 0x00 0x10000>;
reset-names = "serial";
};
3. Pinmux Configuration:
127 (uart4_rx_ph4):
pull=0
tristate=1
enable-input=1
open-drain=0
io-reset=0
rcv-sel=0
io-hv=0
schmitt=0
pull-down-strength=0
pull-up-strength=0
drive-type=0
gpio-mode=0
function=uartd
128 (uart4_tx_ph3):
pull=0
tristate=0
enable-input=0
open-drain=0
io-reset=0
rcv-sel=0
io-hv=0
schmitt=0
pull-down-strength=0
pull-up-strength=0
drive-type=0
gpio-mode=1
function=uartd
4. dmesg log
5. GPIO Status
root@nvidia-desktop:/home/nvidia# cat /sys/kernel/debug/gpio | grep PH
gpio-391 (PH.00 )
gpio-392 (PH.01 )
gpio-393 (PH.02 )
gpio-394 (PH.03 )
gpio-395 (PH.04 )
gpio-396 (PH.05 )
gpio-397 (PH.06 )
gpio-398 (PH.07 )
root@nvidia-desktop:/home/nvidia#
6. Loopback Test
$ sudo su
# stty -F /dev/ttyTHS3 115200 raw -echo
# cat /dev/ttyTHS3 &
# echo "test" > /dev/ttyTHS3
Result: No data received.