Null-modem emulator tty0uart

Ref:

• http://jake.dothome.co.kr/tty/
• https://bootlin.com/doc/legacy/serial-drivers/
• https://www.oreilly.com/library/view/linux-device-drivers/0596005903/ch18.html
• https://github.com/martinezjavier/ldd3/blob/master/tty/tiny_tty.c

가상으로 하드웨어 UART 장치를 만들려면 아래 조건이 만족되어야 합니다.

• /sys/class/tty/xxx의 링크가 /sys/devices/virtual/tty/xxx면 안 됨
• /sys/class/tty/xxx/device 링크가 존재해야 함
• linux/serial_core.h (uart_driver <-> tty_driver)
• normal serial ports == N_TTY
• platform_device와 platform_driver의 name이 같아야 연결 됨

Git

Git: https://github.com/hhk7734/tty0uart

Flow control

• DCD: Data Carrier Detect
• RXD: Receive Data
• TXD: Transmit Data
• DTR: Data Terminal Ready
• DSR: Data Set Ready
• RTS: Request To Send
• CTS: Clear To Send
• CD: Carrier Detect
• RI: Ring Indicator

TXD -> RXD

RTS -> CTS

DTR -> DSR