¶ Uart usage
Rockchip UART (Universal Asynchronous Receiver/Transmitter) is based on the 16550A serial port standard. The complete module supports the following
functions:
- Supports 5, 6, 7, and 8 bits of data bits.
- Supports 1, 1.5, and 2 bits of stop bits.
- Supports odd and even parity checks, but does not support mark and space parity checks.
- Supports receive FIFO and transmit FIFO, which are generally 32 bytes or 64 bytes.
- Supports a maximum baud rate of 4M. The actual supported baud rate requires the cooperation of the chip clock division strategy.
- Supports interrupt transmission mode and DMA transmission mode.
- Supports hardware automatic flow control, RTS+CTS.
Note that the functions supported by the UART in the actual chip should be based on the description of the UART chapter in the chip manual. Some UART functions will be appropriately
cut.
¶ 1 View nodes
The YY3588 development board provides a total of 4 uarts for customers to use, registered as ttyS1, ttyS6, ttyS7, ttyS9
Please refer to the schematic diagram for the corresponding hardware position
$ ls /dev/ttyS*
/dev/ttyS1 /dev/ttyS6 /dev/ttyS7 /dev/ttyS9
¶ 2 Verify whether uart can be used
Short-circuit the target serial port rx and tx (take uart1 as an example)
$ sudo su
#
# View serial port information
# stty -F /dev/ttyS1
# Set the serial port baud rate to 115200
# stty -F /dev/ttyS1 speed 115200
# Set the serial port to eight data bits, no check, one stop bit, no echo
# stty -F /dev/ttyS1 cs8 -parenb -cstopb -echo
# loopback test
# cat /dev/ttyS1 &
# echo -e "youyeetoo\n" > /dev/ttyS1
