L0 ROM: Difference between revisions
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[[File:aes_lo.jpg|right|thumb|Toshiba LO ROM chip taken from an AES system.]] | [[File:aes_lo.jpg|right|thumb|Toshiba LO ROM chip taken from an AES system.]] | ||
[[File:cd2_lo.jpg|right|thumb|LO ROM chip found on a CDM3-2 board.]] | [[File:cd2_lo.jpg|right|thumb|LO ROM chip found on a CDM3-2 board.]] | ||
The L0 ROM is a 64KiB (sometimes 128KiB with A16 tied to ground) ROM chip found in every NeoGeo systems, which contains byte values used by {{Chipname|LSPC}} to shrink [[sprites]] '''vertically'''. | The L0 ROM is a 64KiB (sometimes 128KiB with A16 tied to ground) ROM chip found in every NeoGeo systems as a stand alone chip or integrated in another [[NEO-GRZ|chip]], which contains byte values used by {{Chipname|LSPC}} to shrink [[sprites]] '''vertically'''. | ||
The dump is called 000-lo.lo in [[system ROM]] sets. | The dump is called 000-lo.lo in [[system ROM]] sets. | ||
| Line 9: | Line 8: | ||
=Hash= | =Hash= | ||
* CRC32: | * CRC32: 5A86CFF2 | ||
* SHA-1: | * SHA-1: 5992277DEBADEB64D1C1C64B0A92D9293EAF7E4A | ||
=Data format= | =Data format= | ||
| Line 16: | Line 15: | ||
The data is made of 256 tables of 256 bytes, each table corresponding to a vertical shrinking value for sprites. | The data is made of 256 tables of 256 bytes, each table corresponding to a vertical shrinking value for sprites. | ||
For the first 256 lines ( | For the first 256 lines (top half of a full sprite), the index in the table is the line number of the sprite currently being drawn (scanline - Y position). | ||
Each byte is used as 2 nibbles: | Each byte entry in the table is used as 2 nibbles: | ||
*The upper nibble is the tile number index to read in the tilemap in [[VRAM]] SCB1 (0 to 15). | *The upper nibble is the tile number index to read in the tilemap in [[VRAM]] SCB1 (0 to 15). | ||
*The lower nibble is the line number of that tile to fetch in the [[C ROM]]s. | *The lower nibble is the line number of that tile to fetch in the [[C ROM]]s. | ||
For the last 256 lines ( | For the last 256 lines (bottom half of a full sprite), the index in the table is complemented: the table is read backwards. | ||
*The upper nibble is the tile number index XOR $1F to read in the tilemap in VRAM SCB1 (16 to 31). | |||
*The upper nibble is the tile number index XOR $1F to read in the tilemap in VRAM SCB1 ( | |||
*The lower nibble is the line number XOR $F of that tile to fetch in the C ROMs. | *The lower nibble is the line number XOR $F of that tile to fetch in the C ROMs. | ||
==Example of GPU processing== | ==Example of GPU processing== | ||
[[File:Ngscaling.png|right|thumb]] | |||
(Maybe place this part in the | (Maybe place this part in the LSPC page ?) | ||
Sprite with Y zoom value = $1B and tile height = 2 (32 pixels). | Sprite with Y zoom value = $1B and tile height = 2 (32 pixels). | ||
{|class=wikitable | |||
!Sprite line # | |||
!L0 address | |||
... | !L0 data | ||
!Tilemap index | |||
!Tile line used | |||
|- | |||
|0||$1B00||$00||0||0 | |||
... | |- | ||
|1||$1B01||$08||0||8 | |||
|- | |||
|2||$1B02||$10||1||0 | |||
|- | |||
|colspan=5|... | |||
|- | |||
|26||$1B1A||$E8||14||8 | |||
|- | |||
|27||$1B1B||$F8||15||8 | |||
|- | |||
|28||$1B1C||$FF||15||15 | |||
|- | |||
|29||$1B1D||$FF||15||15 | |||
|- | |||
|colspan=5|... | |||
|} | |||
==Datasheet== | ==Datasheet== | ||
There are 2 stand alone chip versions used depending on the NeoGeo system, the SOP32 TC531001 and the DIP28 TC531000. | |||
Official TC531001 datasheet: [[http://www.alldatasheet.com/datasheet-pdf/pdf/115078/TOSHIBA/TC531001.html]] | Official TC531001 datasheet: [[http://www.alldatasheet.com/datasheet-pdf/pdf/115078/TOSHIBA/TC531001.html]] | ||
Official TC531000 datasheet: [[https://www.digchip.com/datasheets/parts/datasheet/710/TC531000CP-pdf.php]] | |||
[[Category:Chips]] | [[Category:Chips]] | ||
Latest revision as of 21:37, 21 May 2020
The L0 ROM is a 64KiB (sometimes 128KiB with A16 tied to ground) ROM chip found in every NeoGeo systems as a stand alone chip or integrated in another chip, which contains byte values used by LSPC to shrink sprites vertically.
The dump is called 000-lo.lo in system ROM sets.
Hash
- CRC32: 5A86CFF2
- SHA-1: 5992277DEBADEB64D1C1C64B0A92D9293EAF7E4A
Data format
The data is made of 256 tables of 256 bytes, each table corresponding to a vertical shrinking value for sprites.
For the first 256 lines (top half of a full sprite), the index in the table is the line number of the sprite currently being drawn (scanline - Y position).
Each byte entry in the table is used as 2 nibbles:
- The upper nibble is the tile number index to read in the tilemap in VRAM SCB1 (0 to 15).
- The lower nibble is the line number of that tile to fetch in the C ROMs.
For the last 256 lines (bottom half of a full sprite), the index in the table is complemented: the table is read backwards.
- The upper nibble is the tile number index XOR $1F to read in the tilemap in VRAM SCB1 (16 to 31).
- The lower nibble is the line number XOR $F of that tile to fetch in the C ROMs.
Example of GPU processing
(Maybe place this part in the LSPC page ?)
Sprite with Y zoom value = $1B and tile height = 2 (32 pixels).
| Sprite line # | L0 address | L0 data | Tilemap index | Tile line used |
|---|---|---|---|---|
| 0 | $1B00 | $00 | 0 | 0 |
| 1 | $1B01 | $08 | 0 | 8 |
| 2 | $1B02 | $10 | 1 | 0 |
| ... | ||||
| 26 | $1B1A | $E8 | 14 | 8 |
| 27 | $1B1B | $F8 | 15 | 8 |
| 28 | $1B1C | $FF | 15 | 15 |
| 29 | $1B1D | $FF | 15 | 15 |
| ... | ||||
Datasheet
There are 2 stand alone chip versions used depending on the NeoGeo system, the SOP32 TC531001 and the DIP28 TC531000.
Official TC531001 datasheet: [[1]]
Official TC531000 datasheet: [[2]]