Difference between revisions of "NEO mapper/Extension"
From MSX Game Library
| Line 44: | Line 44: | ||
=== Functions === | === Functions === | ||
| − | ==== | + | ==== 0x00: Cartridge information ==== |
| − | When activated, any read access to the given bank will return the cartridge information (8 KB, mirrored on NEO-16). | + | When activated, any read access to the given bank will return the cartridge information (8 KB, mirrored on NEO-16). |
{| class="wikitable" | {| class="wikitable" | ||
|+ PARAMETER | |+ PARAMETER | ||
|- | |- | ||
| − | ! 7 || 6 || 5 || 4 || 3 || 2 || 1 | + | ! 8 || 7 || 6 || 5 || 4 || 3 || 2 || 1 |
|- | |- | ||
|style="background-color:#BBB;"| 0 | |style="background-color:#BBB;"| 0 | ||
| Line 57: | Line 57: | ||
|style="background-color:#BBB;"| 0 | |style="background-color:#BBB;"| 0 | ||
|style="background-color:#AAF;" colspan="5"| Bank | |style="background-color:#AAF;" colspan="5"| Bank | ||
| + | |} | ||
| + | ==== 0x01: Cartridge configuration ==== | ||
| + | |||
| + | ==== 0x04: Activate SRAM/FRAM ==== | ||
| + | When activated, any read/write access to the specified bank (set as a parameter) is redirected to the given segment of the SRAM/FRAM. | ||
| + | SRAM/FRAM are accessed via 8 KB segments (on the NEO-16, the segment is mirrored). | ||
| + | Up to 16 segments can be accessed, for a total of 128 KB. | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |+ PARAMETER | ||
| + | |- | ||
| + | ! 8 || 7 || 6 || 5 || 4 || 3 || 2 || 1 | ||
| + | |- | ||
| + | |style="background-color:#AAF;" colspan="4"| Segment | ||
| + | |style="background-color:#BBB;"| 0 | ||
| + | |style="background-color:#AAF;" colspan="5"| Bank | ||
|} | |} | ||
Revision as of 19:16, 6 April 2026
Proposal for an extension to the NEO mapper format.
Contents
Specifications
Principles
Any write operation to the NEO mapper with data bit 7 set to 1 and address bit 0 set to 1 is considered an access to extended features. All other write operations should be considered normal access to the mapper's bank register.
The data contains:
- The number of an extended function in the mapper
- A bit indicating whether the function should be enabled or disabled
The address contains an 8-bit parameter to be passed to the function.
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Functions
0x00: Cartridge information
When activated, any read access to the given bank will return the cartridge information (8 KB, mirrored on NEO-16).
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | ||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | Bank | ||||
0x01: Cartridge configuration
0x04: Activate SRAM/FRAM
When activated, any read/write access to the specified bank (set as a parameter) is redirected to the given segment of the SRAM/FRAM. SRAM/FRAM are accessed via 8 KB segments (on the NEO-16, the segment is mirrored). Up to 16 segments can be accessed, for a total of 128 KB.
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | ||
|---|---|---|---|---|---|---|---|---|---|
| Segment | 0 | Bank | |||||||