devc-ser* options

Updated: May 06, 2022

Generic options for serial drivers (QNX Neutrino)

Description:

All serial character drivers support the generic options described below.

Note: Individual serial drivers can override these options and typically support additional driver-specific options. The order of precedence is as follows:
  1. board-specific options
  2. generic options

Generic options

-b number

Set the baud rates. The supported baud rates depend on the board that the driver is running on. Default baud rate is 57600.

-C size
The size of the canonical buffer in bytes (default 256).
-E
Set options to “raw” (default). Software flow control is disabled by default.
When set in raw mode, the following terminal flags are initialized:
c_cflag = CREAD | CS8 | IHFLOW | OHFLOW | HUPCL;
c_iflag = IMAXBEL | INPCK;
c_lflag = 0;
c_oflag = ONLCR;

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

Options Mode Software flow control
-E Raw Disabled
-s -E Raw Disabled
-E -s Raw Enabled
-e
Start in edited mode (default raw). Software flow control is enabled by default.
When set in edited mode, the following terminal flags are initialized:
c_cflag = CREAD | CS8 | HUPCL;
c_iflag = IMAXBEL | INPCK | BRKINT | ICRNL | IXON | IXOFF;
c_lflag = ECHO | ECHOCTL | ECHOE | ECHOKE | ICANON | ISIG | IEXTEN;
c_oflag = ONLCR | OPOST;

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

Options Mode Software flow control
-e Edited Enabled
-S -e Edited Enabled
-e -S Edited Disabled
-F
Disable hardware flow control. The default depends on the mode: in raw mode (-E, the default), hardware flow control is enabled; in edited mode (-e), hardware flow control is enabled. Hardware flow control isn't supported in edited mode.
-f
Enable hardware flow control. The default depends on the mode: in raw mode (-E, the default), hardware flow control is enabled; in edited mode (-e), hardware flow control is enabled. Hardware flow control isn't supported in edited mode.
-I number
The size of the raw input buffer in bytes. The default is 2048.
-O number
(“Oh”) The size of the output buffer in bytes. The default is 2048.
-o opt[,opt...]
Additional options, separated by commas. The options include:
  • devperm — Set permissions to the serial device.
  • disable=rx — Disable the UART receiver on driver startup.
  • highwater=prio — Set the receive highwater mark for input flow control. This specifies when to assert input flow control based on the byte level in ibuf.
  • log=flow[@directory_path]—Specify whether to log data for receive, transmit, or both. If directory_path isn't specified, the default log directory is /dev/shmem. Specify one of these values for flow:
    • tx — transmit data only
    • rx — receive data only
    • all — both transmit and receive
  • nodaemon — Don't call procmgr_daemon() to make the driver run in the background. Use this option if you need to know when the device terminates.
  • priority=prio — Set the working priority of the internal pulse as a numeric value.
  • smmu=0|1|off|on — (QNX Neutrino 7.0.4 or later) Specify whether or not support for the system memory management unit (IOMMU/SMMU) manager is required:
    • 0 or off — disable SMMU support. This is the default.
    • 1 or on — SMMU support is required; the driver exits if it isn't available

    For more information, see the SMMUMAN User's Guide.

-s
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.
-S
Disable 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.
-v[v]...
Be verbose; additional v characters cause more verbosity.