My manual refers to the serial ports by number but Linux identifies the ports using tty devices. Which port corresponds to which tty device?
Most of our documents refer to the serial ports as Serial n or Serial Port n where n is a number or letter. Sometimes you'll also see the ports identified as COMn. For example, the Rev A Bitsy personality board labels the headers for Serial Ports 1 through 3 as COM1, COM2 and COM3. In any case, the tty devices associated with the serial ports are as follows...
On the BitsyG5 and BitsyX boards, the serial devices are:
Serial 1 /dev/ttyS0
Serial 2 /dev/ttyS2
Serial 3 /dev/ttyS1 (debug port)
On the TurboXb boards, the serial devices are:
Serial 1 /dev/ttyS1
Serial 2 /dev/ttyS0 (debug port)
Serial 3 /dev/ttyS2
On all other boards with an XScale CPU (GCX, VGX, etc.), the serial devices are:
Serial 1 /dev/ttyS1
Serial 2 /dev/ttyS2
Serial 3 /dev/ttyS0 (debug port)
The AGX, VGX, and BitsyX QuadUART devices are:
Serial A /dev/ttyS8
Serial B /dev/ttyS9
Serial C /dev/ttyS10
Serial D /dev/ttyS11
On boards that have an StrongARM CPU (i.e. SA1100 or SA1110), the serial devices are:
Serial 1 /dev/ttySA1
Serial 2 /dev/ttySA2
Serial 3 /dev/ttySA0 (debug port)
The Graphics Master also has a QuadUART. The devices for these ports are:
Serial A /dev/ttyS0
Serial B /dev/ttyS1
Serial C /dev/ttyS2
Serial D /dev/ttyS3
Which serial port is the console?
By default, the kernel uses Serial Port 3 as the console (/dev/console). You can change this by specifying a different device in the kernel command line. For example, by including:
console=ttyS2
in the command line, you would make Serial Port 2 be the console on an XScale based board.
Which serial port is the debug port?
The bootloader provides status and version messages and reports its progress during boot on the debug port (shown above). This is normally the same port as the console. Changing the console does not change which port the bootloader uses for its output. You can, however, disable the bootloader output by enabling Quiet Mode (see the bootloader documentation for details).
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Posted - 15 Apr 2003 : 15:01:09
