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Caution: This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

devc-ser403, devc-tser403

PowerPC 403 serial communications manager (QNX Neutrino)

Note: You must be root to start this driver.


devc-ser403 [options] &

devc-tser403 [options] &

Runs on:

PowerPC 403


-b number
The initial baud rate (default 57600).
-C size
The size of the canonical buffer in bytes (default 256).
-c clock
Define a custom clock rate for the serial port. The default is suitable for compatible PC serial ports.
Switch to the DTR/DSR pair from the default RTS/CTS pair.
Start in raw mode (the default). Software flow control is disabled by default.
Start in edited mode (default raw). Software flow control is enabled by default.
Disable hardware flow control (default to hardware flow control enabled). Hardware flow control is not supported in edited mode.
Enable hardware flow control (default). Hardware flow control is not supported in edited mode.
-I number
The size of the interrupt input buffer in bytes (default 2048).
-O number
The size of the interrupt output buffer in bytes (default 2048).
Switch to the RTS/CTS pair. This is the default, and can be changed with the -D option.
Disable / enable software flow control. The default depends on the mode: in raw mode (-E, the default), it's disabled; in edited mode (-e), it's enabled.

The order in which you specify the -E or -e, and -S or -s options matters:

Options Mode Software flow control
-e Edited Enabled
-S -e Edited Enabled
-e -S Edited Disabled
-E Raw Disabled
-s -E Raw Disabled
-E -s Raw Enabled
-u number
Append number to the device name prefix (/dev/ser). The default is 1; additional devices are given increasing numbers.


The devc-ser403 manager is a small serial device manager for QNX Neutrino. It supports the builtin serial port present in the PowerPC 403.

The devc-tser403 manager is a "tiny" version of devc-ser403 that's intended for memory-constrained systems. It doesn't support special character editing (e.g. toggling insert mode, special erase characters).

The port is given a name in the pathname space of /dev/sern, where n starts at 1 (unless overridden via the -u option) and increases.

Note: If your application uses /dev/console, you should create a link from it to one of /dev/ser1, /dev/ser2, ... by adding a line like this to the buildfile used by mkifs:
[type=link] /dev/console = /dev/ser1

The port is fully interrupt driven and by default supports standard hardware flow control on input and output (RTS/CTS). This can be disabled by the -F option.

Note: Hardware flow control is not supported in edited mode.

A read request by default returns when at least 1 character is available. To increase efficiency, you can control three parameters to control when a read is satisfied:

Return after a specified amount of time has elapsed.
Return when this number of characters are in the input buffer.
Return if this forwarding character is in the input buffer.

Note: If the Min value is greater than the size of the input buffer, the Min value is clipped to the size of the buffer. To avoid this, the size of the input buffer can be changed with the -I option.

These parameters are set using library routines (see tcgetattr(), tcsetattr(), readcond() and TimerTimeout() in the Library Reference).

The devc-ser403 manager supports both raw and edited modes, making it a real tty device.

The following fields and flags are supported in the termios structure:

Field Supported flags
c_cc All characters
c_oflag OPOST


Start devc-ser403:

devc-ser403 &

See also:

Character I/O drivers (devc-*) in the Utilities Summary

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