Selects a display
|Character stream (hex)|| |
|Description|| Changes the display to |
VDU 22,n changes the display to
MODE n. For a list of display modes, see
- The start of display memory is moved, but the current language is not informed.
- The CRTC, video ULA and address translation latches are reprogrammed, taking into account the
- Changing to a graphics mode, the actions of
VDU 20are performed:
- The text and graphics windows are reset to fill the whole display.
- The text and graphics cursors are uncoupled.
- The text window (the whole screen) is cleared.
- Paged mode is turned off.
- The text cursor is made visible and returned home.
Since the display memory may 'explode' without the current language being informed,
VDU 22,n can corrupt user memory in the I/O processor. Mode changes must therefore be made through the language (for instance in BASIC, by the statement
When user memory is separate from display memory (that is, when
*SHADOW mode, a Tube coprocessor or the Archimedes is in use) then mode changes can be made by either method.
The start of display memory for a given
MODE can be found without changing to that
MODE, with OSBYTE &85.
|Screen display MODEs|
MODE 0 | MODE 1 | MODE 2 | MODE 3 | MODE 4 | MODE 5 | MODE 6 | MODE 7
beardo 20:52, 10 November 2007 (UTC)