Rockchip UART (Universal Asynchronous Receiver/Transmitter) is based on the 16550A serial port standard. The complete module supports the following
Function:
- Supports 5, 6, 7, and 8 bits data bits.
- Supports 1, 1.5, and 2 bits stop bits.
- Supports odd and even parity, but does not support mark and space parity.
- Supports receive FIFO and send FIFO, generally 32 bytes or 64 bytes.
- Supports up to 4M baud rate. Actual support of the baud rate requires the cooperation of the chip clock frequency division strategy.
- Supports interrupt transfer mode and DMA transfer mode.
- Support hardware automatic flow control, RTS+CTS.
Rockchip UART ensures stability for commonly used baud rates, such as 115200, 460800, 921600, 1500000, 3000000, 4000000, etc.
support. For some special baud rates (we do not provide support for special baud rates), it may be necessary to modify the working clock frequency division strategy to support it.
¶ Uart pin
Hot Wheels Technology has developed a rk3588s motherboard, youyeetoo R1, which provides 40pin expansion pins, including 3-way uart pins. The pin distribution is shown in the figure below:
The pins are
- UART5_RX_M1和UART5_TX_M1
- UART7_RX_M1和UART7_TX_M1
- UART9_RX_M2和UART9_TX_M2
¶ shell command call
If you want to use shell commands in the Android system, you need to enter the Android command line window through ADB. For tutorials on using ADB, please refer to the adb debugging chapter. After opening the Android system command line through adb.
- Enter the Android system command line
adb root
adb shell
- View serial port information
stty -F /dev/ttyS5
- Set the serial port baud rate to 115200
stty -F /dev/ttyS5 speed 115200
- Set eight data bits of the serial port, no parity, one stop bit, no echo
stty -F /dev/ttyS5 cs8 -parenb -cstopb -echo
- Receive data in the background and send data in the foreground
cat /dev/ttyS5 &
echo -e "12345\n" > /dev/ttyS5