Register - Bitmap Data: Difference between revisions
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NerdOfEpic (talk | contribs) (Created page with "To load data into the bitmap graphics buffers you must stream it into place 1 byte at a time. Without this approach it's not possible to address 192K bytes of data with a 16-bit address bus on the 65C02 CPU. First, set the address where data will be placed, then set the data that goes in that spot. === Address === {| class="wikitable" ! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0 |- ! Byte 0 | A || A || A || A || A || A || A || A |- ! Byte 1 | A || A || A || A || A...") |
NerdOfEpic (talk | contribs) No edit summary |
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| Line 5: | Line 5: | ||
! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0 | ! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0 | ||
|- | |- | ||
! | ! $02E8 | ||
| A || A || A || A || A || A || A || A | | A || A || A || A || A || A || A || A | ||
|- | |- | ||
! | ! $02E9 | ||
| A || A || A || A || A || A || A || A | | A || A || A || A || A || A || A || A | ||
|- | |- | ||
! | ! $02EA | ||
| - || - || - || - || - || - || A || A | | - || - || - || - || - || - || A || A | ||
|} | |} | ||
| Line 22: | Line 22: | ||
! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0 | ! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0 | ||
|- | |- | ||
! | ! $02EF | ||
| D || D || D || D || D || D || D || D | | D || D || D || D || D || D || D || D | ||
|} | |} | ||
| Line 28: | Line 28: | ||
''' Key ''' | ''' Key ''' | ||
* D - Data to set in the bitmap buffer. | * D - Data to set in the bitmap buffer. | ||
This register is a part of the [[Control Page]]. | |||
Latest revision as of 21:58, 21 January 2024
To load data into the bitmap graphics buffers you must stream it into place 1 byte at a time. Without this approach it's not possible to address 192K bytes of data with a 16-bit address bus on the 65C02 CPU. First, set the address where data will be placed, then set the data that goes in that spot.
Address
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|
| $02E8 | A | A | A | A | A | A | A | A |
| $02E9 | A | A | A | A | A | A | A | A |
| $02EA | - | - | - | - | - | - | A | A |
Key
- A - Address in the bitmap buffer where data will be written.
Data
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|
| $02EF | D | D | D | D | D | D | D | D |
Key
- D - Data to set in the bitmap buffer.
This register is a part of the Control Page.
