9. UART Usage¶

9.1. Description¶

AIO-3576C use UART3 for RS485, which is /dev/ttyS3 in system. And UART8 for RS232, which is /dev/ttyS8 in system.

Interfaces:

_images/usage_uart_interface.jpg

_images/usage_uart_interface2.jpg

9.2. RS485 Usage¶

# set transceiver control pin, high level transmit, low level receive
sudo echo 22 > /sys/class/gpio/export
sudo echo out > /sys/class/gpio/gpio24/direction
# close echo
sudo stty -F /dev/ttyS3 -echo
# transmit
sudo echo 1 > /sys/class/gpio/gpio22/value
sudo echo "firefly uart test..." > /dev/ttyS3
# receive
sudo echo 0 > /sys/class/gpio/gpio22/value
sudo cat /dev/ttyS3