devc-con, devc-tcon

Simple console and keyboard I/O manager (QNX Neutrino)

You must be root to start this manager.

Syntax:

devc-con [options] &

devc-tcon [options] &

Runs on:

All supported platforms.

Options:

-C size

Specify the size of the canonical buffer in bytes (default 256).

-E

Start in raw mode.

-e

Start in edited mode (the default).

-I size

Specify the size of the interrupt input buffer in bytes (default 2048).

-k

(devc-con only) Disable keyboard (don't attach a keyboard interrupt handler).

-L [P][N][C][S]

Set the initial state of the keyboard and its LEDs (default all off):

• C -- turn CapsLock on.
• P -- preserve the keyboard state. This overrides all the other -L options.
• N -- turn NumLock on.
• S -- turn ScrollLock on.

-n num_ports

(devc-con only) The number of virtual console ports to create. The default is 4; the maximum is 9.

-O size

Specify the size of the interrupt output buffer in bytes (default 2048).

-r rate[,delay]

Specify the initial keyboard typematic rate (in Hz) and, optionally, the initial keyboard delay (in ms). The default values are 30 Hz and 500 ms.

The keyboard typematic rate is the number of times per second that a depressed key repeats. On a PC/AT-compatible system, this ranges from 2 - 30 characters per second. If the option -r 0 is specified, the keyboard typematic rate isn't set by the driver.

The keyboard delay is defined as the time from when a key is first pressed to when the start of the first repeated key is generated. On a PC/AT-compatible system, the keyboard delay can range from 250 - 1000 milliseconds.

Description:

The devc-con manager provides an interface to the console screen and keyboard. It's usually started as a system startup procedure (see diskboot). When devc-con starts, it creates and manages the devices /dev/con1, /dev/con2, and so on, up to the number of ports specified by the -n option.

The devc-tcon manager is a "tiny" implementation of devc-con that's intended for memory-constrained systems. It doesn't support special character editing (e.g. toggling insert mode, special erase characters). When devc-tcon starts, it creates and manages only the device /dev/con1.

The devc-con manager reads from /dev/console return characters typed on the keyboard and writes output to the screen.

If your application uses /dev/console, you should create a link from it to one of /dev/con1, /dev/con2, ... by adding a line like this to the buildfile used by mkifs: [type=link] /dev/console = /dev/con1

Both devc-con and devc-tcon emulate an 80*25 ANSI terminal. However, devc-tcon supports only a small subset of the full ANSI control codes.

Keyboard control

You can use the keyboard to switch between virtual consoles.

Each virtual console can run different applications that use the entire screen. The keyboard is attached to the virtual console that's currently visible. You can switch from one virtual console to another -- and thus from one application to another -- by entering the following keychords:

The + (plus) and - (minus) keys used in the console-switching keychords are those found on the numeric keypad.

You can also jump to a specific console by using the Ctrl-Alt-n, where n is a numeric digit that represents the console number of a virtual console. For instance:

Character sets

The devc-con driver allows the character sets in use to be chosen from a "palette" of character sets, each of which is independently programmable to contain one of several builtin character sets.

The in-use range of characters is divided into four regions which span character numbers (in hexadecimal) 0x00 through 0xff. Two of these regions are fixed sets of control characters, while the other two are configurable to contain a choice of character sets:

You can set each of the GL and GR in-use character sets to a choice of several character sets from the G0, G1, G2 and G3 character sets.

The screen control codes to set GL and GR are as follows:

The {LS*} codes stand for "Locking Shift". When character sets are selected by these means, they remain in effect until another {LS*} code is sent.

The {SS*} codes stand for "Single Shift" and affect the next character only. After that character, the character set in effect reverts to its previous setting. There are only two {SS*} codes, {SS2} and {SS3} which maps G2 into GL and G3 into GL, respectively.

The G0 through G3 characters sets may each be set to any of the available builtin fonts. The control code to do this is:

   ESC g s

Where:

And:

Character set defaults

The in-use character sets are as follows:

The character set codes are as follows:

Character set example:

Set the GL in-service character set (0x20-0x7f) to the PC character set through G1, write some characters, then switch GL back to G0:

{ESC )U}  1e 29 55    (Set G1 to be the PC character set)
{SO}      0e          (Set GL to G1)
.
.                     (Write chars in PC graphics char set)
.
{SI}      0f          (Set GL to G0)

The PC character set 0x00-0x7f.

The PC character set 0x80-0xff.

ANSI screen control codes

Note the following abbreviations used in the tables: (220+) A VT220 Level 2 function (NA) Not ANSI standard (NI) Not implemented (NFI) Not fully implemented

C0 control codes

The C0 control codes are as follows:

ESC control sequences

The ESC control sequence codes are as follows:

C1 control characters (220+)

You can do any 8-bit C1 code with 7-bit ESC followed by the 8-bit code minus 0x40 hex. For instance, you can represent the CSI (control sequence introducer) in 8-bit mode as 0x9b, while in 7-bit mode you must express it as ESC [ (0x1b 0x5b).

The C1 control character codes are as follows:

CSI control sequences

In 7-bit mode, CSI is ESC [. In 8-bit mode, CSI is (hex)0x9B. Use the ANSI specification to represent the variable n, e.g. to print two spaces: printf( "%c%c", 0x9b, 0x32 ) ;

The CSI control sequence codes are as follows:

Graphic rendition

The graphic rendition codes are as follows:

Color numbers

The color codes are as follows:

Modes

Modes are as follows:

Mapping from QNX keyboard to ANSI keys

The ANSI key mapping codes are as follows:

Examples:

Typical command line:

devc-con -n4

Files:

/dev/con1, /dev/con2, ...

console port devices

devc-con

the devc-con program is normally to be found in /sbin.

Errors:

If an error occurs in devc-con, the keyboard will not work in text mode.

See also:

Using the Command Line and Controlling How Neutrino Starts in the Neutrino User's Guide