NEO mapper - Revision history

Aoineko at 21:05, 13 April 2026

2026-04-13T21:05:19Z

Aoineko at 21:04, 13 April 2026

2026-04-13T21:04:14Z

Aoineko: +2 bits for segment number

2026-04-06T20:04:30Z

+2 bits for segment number

Aoineko: /* Logos */

2026-04-06T09:58:21Z

‎Logos

Aoineko: /* Bank switching cost */

2026-04-05T23:09:54Z

‎Bank switching cost

Aoineko: /* Logos */

2026-04-05T20:41:34Z

‎Logos

Aoineko: /* Logos */

2026-04-05T20:41:23Z

‎Logos

Aoineko: /* Emulator */

2026-03-14T01:01:28Z

‎Emulator

Aoineko: /* Hardware */

2026-03-14T01:00:49Z

‎Hardware

Aoineko: /* Logo */

2026-03-14T00:55:15Z

‎Logo

@@ Line 297: / Line 297: @@
 ** Added clarification for read access to the mapper and especially when try to read the page 3.
 * Version 1.2 (2026/04/06)
-** Added official logo for NEO mapper product.
+** Added optional official logo for NEO mapper product.
 ** Added bits 12 and 13 to the register value, increasing the maximum number of segments from 4096 to 16384.
 [[Category:Proposal]][[Category:Proposal/Mapper]]

@@ Line 297: / Line 297: @@
 ** Added clarification for read access to the mapper and especially when try to read the page 3.
 * Version 1.2 (2026/04/06)
-** Add bits 12 and 13 to the register value, increasing the maximum number of segments from 4096 to 16384
+** Added official logo for NEO mapper product.
 [[Category:Proposal]][[Category:Proposal/Mapper]]

@@ Line 19: / Line 19: @@
 Usage of page #0 makes it easy to have an extra 16 KB accessible at any time (either by temporarily disabling interrupts for the duration of accesses, or by adding its own ISR).
-For the time being, we propose to reserve the 4 most significant bits of the 16-bit bank registers for future extensions of the format (such as SRAM or sound chips support for example).
+For the time being, we propose to reserve the 2 most significant bits of the 16-bit bank registers for future extensions of the format (such as SRAM or sound chips support for example).
-This leaves 12 bits to select which segment is visible in each bank, for a maximum of 4096 segments.
+This leaves 14 bits to select which segment is visible in each bank, for a maximum of 16384 segments.
 The reserved bits, must be set to 0.
@@ Line 33: / Line 33: @@
 ! 7 || 6 || 5 || 4 || 3 || 2 || 1 || 0
 |-
-| 0 || 0 || 0 || 0
+| 0 || 0
-|colspan="4"| Segment MSB
+|colspan="6"| Segment MSB
+|
 |colspan="8"| Segment LSB
 |}
-The maximum ROM size is therefore 32 MB (for 8 KB segments) or 64 MB (for 16 KB segments).
+The maximum ROM size is therefore 128 MB (for 8 KB segments) or 256 MB (for 16 KB segments).
 === Write Access ===
@@ Line 69: / Line 69: @@
 | 5: A000h~BFFFh || 7800h (mirror at 3800h, B800h and F800h) || 0000h
 |}
-* Maximum number of segments: 4096
+* Maximum number of segments: 16384
-* Maximum ROM size: 32 MB
+* Maximum ROM size: 128 MB
 ==== NEO-16 mapper ====
@@ Line 85: / Line 85: @@
 | 2: 8000h~BFFFh || 7000h (mirror at 3000h, B000h and F000h) || 0000h
 |}
-* Maximum number of segments: 4096
+* Maximum number of segments: 16384
-* Maximum ROM size: 64 MB
+* Maximum ROM size: 256 MB
 === Read Access ===
@@ Line 296: / Line 296: @@
 ** Added clarification on PP and BBB values for bank switching addresses.
 ** Added clarification for read access to the mapper and especially when try to read the page 3.
+* Version 1.2 (2026/04/06)
 [[Category:Proposal]][[Category:Proposal/Mapper]]

@@ Line 284: / Line 284: @@
 Here are the logos you can use to indicate that a product is compatible with the NEO mapper:
-[https://aoineko.org/msx/files/neomapper8b-logo.png <img style="width:100px" src="https://aoineko.org/msx/files/neomapper8b-logo.png" />]
+[https://aoineko.org/msx/files/neomapper8b-logo.png <img style="width:128px" src="https://aoineko.org/msx/files/neomapper8b-logo.png" />]
-[https://aoineko.org/msx/files/neomapper8w-logo.png <img style="width:100px" src="https://aoineko.org/msx/files/neomapper8w-logo.png" />]
+[https://aoineko.org/msx/files/neomapper8w-logo.png <img style="width:128px" src="https://aoineko.org/msx/files/neomapper8w-logo.png" />]
-[https://aoineko.org/msx/files/neomapper16b-logo.png <img style="width:100px" src="https://aoineko.org/msx/files/neomapper16b-logo.png" />]
+[https://aoineko.org/msx/files/neomapper16b-logo.png <img style="width:128px" src="https://aoineko.org/msx/files/neomapper16b-logo.png" />]
-[https://aoineko.org/msx/files/neomapper16w-logo.png <img style="width:100px" src="https://aoineko.org/msx/files/neomapper16w-logo.png" />]
+[https://aoineko.org/msx/files/neomapper16w-logo.png <img style="width:128px" src="https://aoineko.org/msx/files/neomapper16w-logo.png" />]
 == Change log ==

@@ Line 274: / Line 274: @@
 LD (nn),HL  ; 17 t-states
-; Indirect access (45 t-states)
+; Indirect access (40 t-states)
 LD HL,nn    ; 11 t-states
-LD (HL),E   ;  8 t-states
+LD (HL),n   ; 11 t-states
 INC HL      ;  7 t-states
-LD (HL),D   ;  8 t-states
+LD (HL),n   ; 11 t-states
 </syntaxhighlight>

@@ Line 116: / Line 116: @@
 Emulators supporting NEO mapper:
 * {{Emulicious}} '''Emulicious''': Full support for NEO-8 and NEO-16 mappers.
-* {{MSXEC}} '''MSXEC''': ''Support NEO-8 and NEO-16 mappers up to 64 MB (version 20260303 or above).
+* {{MSXEC}} '''MSXEC''': Support NEO-8 and NEO-16 mappers up to 64 MB (version 20260303 or above).
 * {{openMSX}} '''openMSX''': Full support for NEO-8 and NEO-16 mappers (version 20.0 or above).
 * {{WebMSX}} '''WebMSX''': Full support for NEO-8 and NEO-16 mappers (version 6.0.7 or above).

@@ Line 108: / Line 108: @@
 Hardware supporting NEO mapper:
 * '''[https://www.msxpico.com/ MSX Pico]''' (normal or WiFi): Support for NEO-8 and NEO-16 mappers up to ~15 MB (firmware 1.25 or above).
-* '''[https://www.msxpico.com/ MSX Pico+)''': Support for NEO-8 and NEO-16 mappers up to ~14 MB (firmware 2.12 or above).
+* '''[https://www.msxpico.com/ MSX Pico+]''': Support for NEO-8 and NEO-16 mappers up to ~14 MB (firmware 2.12 or above).
 * '''[https://github.com/cristianoag/msx-picoverse-public PicoVerse] 2040 and 2350''': Support for NEO-8 and NEO-16 mappers up to ~15 MB.
 * '''[https://github.com/arkadiuszmakarenko/RISKYMSX RISKY MSX]''': Support for NEO-8 and NEO-16 mappers up to 256 KB.