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Commit de6f86ce authored by Yegor Yefremov's avatar Yegor Yefremov Committed by Greg Kroah-Hartman
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RS485 documentation: add 16C950 UART description 



Add a notion about 16C950 UART, that is using DTR signal for RS485 mode.

Signed-off-by: default avatarYegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a4fb0b22

Documentation/serial/serial-rs485.txt

+5 −4
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2. HARDWARE-RELATED CONSIDERATIONS

2. HARDWARE-RELATED CONSIDERATIONS





   Some CPUs (e.g., Atmel AT91) contain a built-in half-duplex mode capable of

   Some CPUs/UARTs (e.g., Atmel AT91 or 16C950 UART) contain a built-in

   automatically controlling line direction by toggling RTS. That can used to

   half-duplex mode capable of automatically controlling line direction by

   control external half-duplex hardware like an RS485 transceiver or any

   toggling RTS or DTR signals. That can be used to control external

   RS232-connected half-duplex device like some modems.

   half-duplex hardware like an RS485 transceiver or any RS232-connected

   half-duplex devices like some modems.





   For these microcontrollers, the Linux driver should be made capable of

   For these microcontrollers, the Linux driver should be made capable of

   working in both modes, and proper ioctls (see later) should be made

   working in both modes, and proper ioctls (see later) should be made