Difference between revisions of "ULA Control Register"
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(core 3.0 changes/refresh) |
(core 3.1.3 changes/refresh) |
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| 7 || 1 to disable ULA output (soft reset = 0) | | 7 || 1 to disable ULA output (soft reset = 0) | ||
|- | |- | ||
| − | | 6 || 0 to select the ULA colour for blending in SLU modes 6 & 7 (soft reset = 0) | + | | 6-5 || since core3.1.1: Blending in SLU modes 6 & 7 (soft reset = 0) |
| − | 1 to select the ULA/tilemap mix for blending in SLU modes 6 & 7 | + | = 00 for ULA as blend colour |
| + | = 10 for ULA/tilemap as blend colour | ||
| + | = 11 for tilemap as blend colour | ||
| + | = 01 for no blending | ||
| + | <del>bit 6: 0 to select the ULA colour for blending in SLU modes 6 & 7 (soft reset = 0) | ||
| + | 1 to select the ULA/tilemap mix for blending in SLU modes 6 & 7</del> | ||
|- | |- | ||
| − | | | + | | 4 || Reserved, must be 0 |
|- | |- | ||
| 3 || ULA+ enable (soft reset = 0) | | 3 || ULA+ enable (soft reset = 0) | ||
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Bit 0 can be set to choose stencil mode for the combined output of the ULA and [[Tilemap]]. | Bit 0 can be set to choose stencil mode for the combined output of the ULA and [[Tilemap]]. | ||
| − | + | Bits 6-5 determine what colour is used in SLU modes 6 & 7 where the ULA is combined with Layer 2 to generate highlighting effects ({{NextRegNo|$15}}). | |
Revision as of 15:30, 13 April 2020
| Number | $68 |
|---|---|
| Readable | Yes |
| Writable | Yes |
| Short Description | Disable ULA, controls ULA mixing/blending, enable ULA+ |
| Bit | Function |
|---|---|
| 7 | 1 to disable ULA output (soft reset = 0) |
| 6-5 | since core3.1.1: Blending in SLU modes 6 & 7 (soft reset = 0)
= 00 for ULA as blend colour = 10 for ULA/tilemap as blend colour = 11 for tilemap as blend colour = 01 for no blending
|
| 4 | Reserved, must be 0 |
| 3 | ULA+ enable (soft reset = 0) |
| 2 | may change (ULA half pixel scroll) (soft reset = 0) |
| 1 | Reserved, must be 0 |
| 0 | 1 to enable stencil mode when both the ULA and tilemap are enabled
(if either are transparent the result is transparent otherwise the result is a logical AND of both colours) |
Bit 0 can be set to choose stencil mode for the combined output of the ULA and Tilemap.
Bits 6-5 determine what colour is used in SLU modes 6 & 7 where the ULA is combined with Layer 2 to generate highlighting effects (Sprite and Layers System Register ($15)).