diff options
| -rw-r--r-- | Documentation/serial/serial-rs485.txt | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index a3b1af7b6db9..a4932387bbfb 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/Documentation/serial/serial-rs485.txt @@ -11,10 +11,11 @@ 2. HARDWARE-RELATED CONSIDERATIONS - Some CPUs (e.g., Atmel AT91) contain a built-in half-duplex mode capable of - automatically controlling line direction by toggling RTS. That can used to - control external half-duplex hardware like an RS485 transceiver or any - RS232-connected half-duplex device like some modems. + Some CPUs/UARTs (e.g., Atmel AT91 or 16C950 UART) contain a built-in + half-duplex mode capable of automatically controlling line direction by + toggling RTS or DTR signals. That can be used to control external + 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 working in both modes, and proper ioctls (see later) should be made |