MODE 14

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Demonstration of 'MODE 14' (BBC)

MODE 14 is the unofficial title of a low-resolution screen MODE, selectable with the *MODE command or the NewModes sideways ROM module.[1]

The MODE 14 code adapts the MODE 6 screen to provide a 4-colour version of MODE 6, 40 × 32 characters in 4 colours. It does this by redefining the character set to provide thin characters.

'MODE 14'
Type Bitmapped
Resolution Text 40 × 32 characters
Graphics test only
Character size 4 × 8 pixels
Pixel aspect 1:1 (square)
Bits per pixel 2
Default palette Logical colour Actual colour
0 0 (black)
1 1 (red)
2 3 (yellow)
3 7 (white)
Memory allocated 8192 bytes
on screen 8000 bytes
Address range Model B etc. &6000..&7FFF
Configuration Video ULA control register &44
Video ULA palette register file &07 &17 &26 &36
&47 &57 &66 &76
&84 &94 &A0 &B0
&C4 &D4 &E0 &F0
CRTC register file &3F &28 &31 &24
&26 &00 &20 &22
&01 &07 &67 &08

MODE 14 can be created manually with the following code running in the I/O processor.

   BASIC:
   MODE 6     :REM Base MODE
   ?&30A=39   :REM Characters per line
   ?&34F=8    :REM Bytes per character
   ?&360=3    :REM Number of colours
   VDU 20     :REM Reset palette
   *FX154,68
   
   6502:
   LDA #22:JSR OSWRCH
   LDA #05:JSR OSWRCH          \ Base MODE
   LDA #&27:STA &30A           \ Characters per line
   LDA #&08:STA &34F           \ Byte per character
   LDA #&03:STA &360           \ Number of colours
   LDA #20:JSR OSWRCH          \ Reset palette
   LDA #154:LDX #84:JSR OSBYTE \ Cursor width

The character set needs to be redefined to be four pixels wide, such as with the one used with NewModes.

See Also

References

-- Jgharston (talk) 17:11, 12 October 2016 (UTC)