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Jetson Sensor Processing Engine (SPE) Developer Guider32.7.5 Release |
UART application demonstrates how to access/manipulate Always On(AON) UARTs from the SPE/AON processor. Make sure that the kernel/bootloader is not accessing these UARTs (Usually, this can be done by modifying the device tree file). Compilation of this demo app can be controlled by "ENABLE_UART_APP" flag in the soc/*/target_specific.mk file.
There are 2 UART ports in AON cluster for Jetson TX2:
In order to access AON UART from the Cortex-R5 SPE/AON; the UART SCR and Pinmux settings need to be updated to enable access to it as described in below steps.
scr.1862.2 = 0x38001414; # CLK_RST_CONTROLLER_AON_SCR_UARTC_0
tegra186-mb1-bct-pinmux-quill-p3310-1000-a00.cfg
: pinmux.0x0c302020 = 0x00000400; # uart3_tx_pw2: uartc pinmux.0x0c302018 = 0x00000458; # uart3_rx_pw3: uartc
After the UART test task runs, it will continuously output following messages to desired UART port: Message from SPE R5 UART And also print received characters to debug port.
There are 2 UART ports in AON cluster for Jetson AGX:
In order to access a AON UART from the Cortex-R5 SPE/AON for Jetson AGX; the UART SCR, and pinmux settings need to be updated as described in below steps.
scr.2609.6 = 0x18001616; # AON_NOC_UARTG_BLF_CONTROL_REGISTER_0
tegra19x-mb1-pinmux-p2888-0000-a04-p2822-0000-b01.cfg
. pinmux.0x0c302048 = 0x00000401; # spi2_sck_pcc0: uartg, pinmux.0x0c302050 = 0x00000459; # spi2_miso_pcc1: uartg,
Compile device tree and flash the entire board to ensure that the SCR, and pinmux settings are flashed on the board.
After the UART test task runs, it will continuously output following messages to desired UART port:
Message from SPE R5 UART
It will also print received characters to debug port.
A simple way to test UARTG function in Jetson AGX board.
4.1. Follow above steps from 1 to 3 and power up the device.
4.2. Use a wire to connect UARTG TX and Rx (in Jetson AGX board, they are A5 and A6 in J6), then the following message will output from SPE firmware debug UART port:
Message from SPE R5 UART