Difference between revisions of "Sprite Pattern Upload"
(Created page with "{{Port |Number=$xx5B |ShortDesc=Used to upload the pattern of the selected sprite. |Readable=No |Writable=Yes }} Used to upload sprite patterns. Sprite patterns are 16x16 (256...") |
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{{Port | {{Port | ||
|Number=$xx5B | |Number=$xx5B | ||
| + | |NumberDec=91 | ||
| + | |PortMask=%---- ---- 0101 1011 ?? | ||
|ShortDesc=Used to upload the pattern of the selected sprite. | |ShortDesc=Used to upload the pattern of the selected sprite. | ||
|Readable=No | |Readable=No | ||
|Writable=Yes | |Writable=Yes | ||
| + | |Subsystem=Sprites | ||
}} | }} | ||
| − | Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes) and are sent in English reading order. Each byte is the offset, 0-255, within the active sprite palette. After sending 256 bytes, the target | + | Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes for 8 bit colour and 128 bytes for 4 bit colour sprites) and are sent in English reading order. Each byte is the offset, 0-255 (or two 0-15 for 4-bit graphics), within the active sprite palette. After sending 256 bytes, the target pattern slot is auto-incremented. This auto-increment is independent of other sprite registers. |
| + | |||
| + | Auto-increment from pattern slot 63 will wrap to slot 0 (only 64 pattern slots will be available in foreseeable future, and if ever extended, there will be separate configuration bit to enable more than 64 pattern slots). | ||
| + | |||
| + | With 4 bit sprites each pattern slot contains effectively two patterns, each 128 bytes long, the sub-pattern displayed is selected by "N6" bit in 5th sprite-attribute byte. | ||
| + | |||
| + | With 4 bit graphics the top bits (of each pattern byte) 7-4 are "left" pixel on display and bits 3-0 are "right next to it" pixel on display (in default mode, no mirror, no rotate). | ||
Latest revision as of 11:49, 4 May 2020
| Number | $xx5B |
|---|---|
| Decimal | 91 |
| Short desc. | Used to upload the pattern of the selected sprite. |
| Bit Mask | %---- ---- 0101 1011 ?? |
| Readable | No |
| Writable | Yes |
| Subsystem | Sprites |
Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes for 8 bit colour and 128 bytes for 4 bit colour sprites) and are sent in English reading order. Each byte is the offset, 0-255 (or two 0-15 for 4-bit graphics), within the active sprite palette. After sending 256 bytes, the target pattern slot is auto-incremented. This auto-increment is independent of other sprite registers.
Auto-increment from pattern slot 63 will wrap to slot 0 (only 64 pattern slots will be available in foreseeable future, and if ever extended, there will be separate configuration bit to enable more than 64 pattern slots).
With 4 bit sprites each pattern slot contains effectively two patterns, each 128 bytes long, the sub-pattern displayed is selected by "N6" bit in 5th sprite-attribute byte.
With 4 bit graphics the top bits (of each pattern byte) 7-4 are "left" pixel on display and bits 3-0 are "right next to it" pixel on display (in default mode, no mirror, no rotate).