Page D8
Colour memory
Categories:
| Address | Len | Name | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 | Description |
|---|---|---|---|---|---|---|---|---|---|---|---|
| D800 | 1000 | COLMEM | Not Connected | Colour | Colour Memory | ||||||
| D8E8 | 24 | Not Connected | Unused | Unused | |||||||
Memory format
For each character in every row (40 chars per row; 0-39) and column (25 columns; 0-24) one of 16 colors can be assigned. The color values 0-15 are only used in the lower nibbles. The upper nibbles are undefined and are purely random values.
The colour memory is provided by an MM2114N-3 4Kb (1024x4) static RAM chip.
As this chip only provides 4 bits, the upper nibble is random as it's not connected to anything. It is separate from the onboard 64K RAM
Last modified October 21, 2021: Mark unused bytes as being unused on lower 4 bits as it's only a 4-bit wide chip (f621ddb)