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www.riscos.com Technical Support: |
A list of the VDU codes is given in the table below. Some VDU codes require extra bytes to be sent as parameters; for example, VDU 22 (select screen mode) needs one extra byte to specify the mode. The number of extra bytes needed is also given in the table:
| VDU code | Ctrl plus | Extra bytes | Meaning | Page |
|---|---|---|---|---|
| 0 | @ | 0 | Does nothing | VDU 0 |
| 1 | A | 1 | Sends next character to printer only | VDU 1 |
| 2 | B | 0 | Enables printer | VDU 2 |
| 3 | C | 0 | Disables printer | VDU 3 |
| 4 | D | 0 | Writes text at text cursor | VDU 4 |
| 5 | E | 0 | Writes text at graphics cursor | VDU 5 |
| 6 | F | 0 | Enables VDU driver | VDU 6 |
| 7 | G | 0 | Generates bell sound | VDU 7 |
| 8 | H | 0 | Moves cursor back one character | VDU 8 |
| 9 | I | 0 | Moves cursor on one space | VDU 9 |
| 10 | J | 0 | Moves cursor down one line | VDU 10 |
| 11 | K | 0 | Moves cursor up one line | VDU 11 |
| 12 | L | 0 | Clears text window | VDU 12 |
| 13 | M | 0 | Moves cursor to start of current line | VDU 13 |
| 14 | N | 0 | Turns on paged mode | VDU 14 |
| 15 | O | 0 | Turns off paged mode | VDU 15 |
| 16 | P | 0 | Clears graphics window | VDU 16 |
| 17 | Q | 1 | Defines text colour | VDU 17 |
| 18 | R | 2 | Defines graphics colour | VDU 18 |
| 19 | S | 5 | Defines logical colour | VDU 19 |
| 20 | T | 0 | Restores default logical colours | VDU 20 |
| 21 | U | 0 | Disables VDU drivers | VDU 21 |
| 22 | V | 1 | Selects screen mode | VDU 22 |
| 23 | W | 9 | Multi-purpose command: | VDU 23 |
| 23,0 | Sets the interlace and controls cursor appearance | VDU 23,0 | ||
23,1 | Controls text cursor appearance | VDU 23,1 | ||
23,2-5 | Defines ECF pattern and colours | VDU 23,2-5 | ||
23,6 | Sets dot-dash line style | VDU 23,6 | ||
23,7 | Scrolls text window or screen | VDU 23,7 | ||
23,8 | Clears a block of the text window | VDU 23,8 | ||
23,9 | Sets first flash time | VDU 23,9 | ||
23,10 | Sets second flash time | VDU 23,10 | ||
23,11 | Sets default patterns | VDU 23,11 | ||
23,12-15 | Defines simple ECF patterns and colours | VDU 23,12-15 | ||
23,16 | Controls cursor movement after printing | VDU 23,16 | ||
23,17,0-3 | Sets the tint for a colour | VDU 23,17,0-3 | ||
23,17,4 | Chooses ECF patterns | VDU 23,17,4 | ||
23,17,5 | Exchanges text foreground and background colours | VDU 23,17,5 | ||
23,17,6 | Sets ECF origin | VDU 23,17,6 | ||
23,17,7 | Sets character size/spacing | VDU 23,17,7 | ||
23,18-24 | Reserved for future expansion | VDU 23,18-24 | ||
23,25-26 | Private Font Manager calls | VDU 23,25-26 | ||
23,27 | Private Sprite Manager calls | VDU 23,27 | ||
| 23,28-31 | Reserved for use by application programs | VDU 23,28-31 | ||
| 23,32-255 | Redefines printable characters | VDU 23,32-255 | ||
| 24 | X | 8 | Defines graphics window | VDU 24 |
| 25 | Y | 5 | PLOT command | VDU 25 |
| 26 | Z | 0 | Restores default windows | VDU 26 |
| 27 | [ | 0 | Does nothing | VDU 27 |
| 28 | \ | 4 | Defines text window | VDU 28 |
| 29 | ] | 4 | Defines graphics origin | VDU 29 |
| 30 | ^ | 0 | Homes text cursor | VDU 30 |
| 31 | _ | 2 | Moves text cursor | VDU 31 |
| 127 | 0 | Delete | VDU 127 | |