devc-serzscc, devc-tserzscc

Zilog SCC serial communications manager (QNX Neutrino)


Note: You must be root to start this driver.

Syntax:

devc-serzscc [[options] 
              [port[^shift][+offset][,intr]]]... &

devc-tserzscc [[options] 
               [port[^shift][+offset][,intr]]] &

Runs on:

MIPS, x86

Options:

The options are position-dependent and affect the subsequent ports.

-1
Enable only channel A for this device.
-2
Enable both channel A and B for this device.
-b number
The initial baud rate (default 57600).
-C size
The size of the canonical buffer in bytes (default 256).
-c clock[/divisor]
Define a custom clock rate, in hertz, and divisor for the serial port. The default is suitable for compatible serial ports.
-D delay
Inter-register access delay of delay.
-E
Start in raw mode (the default). Software flow control is disabled by default.
-e
Start in edited mode (default raw). Software flow control is enabled by default.
-F
Disable hardware flow control (default to hardware flow control enabled). Hardware flow control is not supported in edited mode.
-f
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).
-S|s
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.
port
Hex physical memory address of a serial port.
shift
The spacing of the registers as a power of 2. For example:
0
Registers are 1 byte apart.
1
Registers are 2 bytes apart.
2
Registers are 4 bytes apart.

...

n
Registers are 2n bytes apart.

The default shift is 0.

offset
Offset to add to the port value.
intr
Decimal interrupt used by this port.

Description:

The devc-serzscc manager is a small serial device manager for QNX Neutrino. It supports the Zilog SCC chip.

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

All devices are fully interrupt driven and by default support 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.


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

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:

Time
Return after a specified amount of time has elapsed.
Min
Return when this number of characters are in the input buffer.
Char
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-serzscc 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_iflag BRKINT ICRNL IGNBRK IXON
c_oflag OPOST
c_cflag CLOCAL CSIZE CSTOPB PARENB PARODD
c_lflag ECHO ECHOE ECHOK ECHONL ICANON IEXTEN ISIG NOFLSH

Examples:

Start devc-serzscc in edited mode, specifying the clock rate, baud rate, and inter-register access delay:

devc-serzscc -e -c4915200/16 -b9600 -D4000 0x81000000^3+4,0x8002 &

See also:

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