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notes:flashcart:r4ds [2023/10/16 14:26] – asienotes:flashcart:r4ds [2023/10/16 15:03] (current) – asie
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 ====== R4 (NDS) programming ====== ====== R4 (NDS) programming ======
  
-Original research provided mostly by lifehackerhansol.+Original research provided mostly [[https://github.com/DS-Homebrew/DLDI/wiki/Original-R4-and-M3-Simply|by lifehackerhansol]].
  
 ===== Control flags ===== ===== Control flags =====
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 ===== Commands ===== ===== Commands =====
  
-==== Get card status (B0 ?? ?? ?? ?? ?? ?? ??) ====+==== Get card status (B0 00 00 00 00 00 00 00) ====
  
 <code> <code>
 31                 bit                 0 31                 bit                 0
- ???? ???? ???? ???? ???? ???m mmmm msss+ ???? ???? ???? ???? ???? ???L LLml lsss
                              | |||| ||||                              | |||| ||||
                              | |||| |+++- Initialization status:                              | |||| |+++- Initialization status:
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                              | |||| |      3 - could not find _DS_MENU.DAT                              | |||| |      3 - could not find _DS_MENU.DAT
                              | |||| |      4 - success                              | |||| |      4 - success
-                             +-++++-+---- Model: +                             | |||+-+---- Language: 
-                                           0x3A - M3DS Simply +                             | |||         1 - Japanese 
-                                           0x3E - R4 Revolution for DS+                             | |||         2 - English 
 +                             | |||         3 - Chinese 
 +                             | ||+------- Model: 
 +                             | ||          0 - M3DS Simply 
 +                             | ||          1 - R4 Revolution for DS 
 +                             +-++-------- Sub-language: 
 +                                           2:2  - French 
 +                                           2:4  - Korean 
 +                                           3:0? - Simplified Chinese 
 +                                           3:1? - Traditional Chinese
 </code> </code>
  
-==== Save read request (B2 sd sc sb sa ?? ?? ??) ====+==== Save read request (B2 sd sc sb sa 00 00 00) ====
  
 SD read request, but using the "save" FAT entry table. SD read request, but using the "save" FAT entry table.
  
-==== Save read data (B3 ?? ?? ?? ?? ?? ?? ??) ====+==== Save read data (B3 00 00 00 00 00 00 00) ====
  
 SD read data, but using the "save" FAT entry table. SD read data, but using the "save" FAT entry table.
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 Points to _DS_MENU.DAT on initialization. Points to _DS_MENU.DAT on initialization.
  
-==== ROM read data (B7 ?? ?? ?? ?? ?? ?? ??) ====+==== ROM read data (B7 00 00 00 00 00 00 00) ====
  
 SD read data, but using the "ROM" FAT entry table. SD read data, but using the "ROM" FAT entry table.
  
-==== ? Get card ID ? (B8 ?? ?? ?? ?? ?? ?? ??) ====+==== Get card ID (B8 00 00 00 00 00 00 00) ==== 
 + 
 +[[https://github.com/DS-Homebrew/DLDI/wiki/Original-R4-and-M3-Simply#original-r4--m3-ds-simply|Quoting lifehackerhansol]]: 
 + 
 +> Card ID commands are not patched and use the timings from the retail game ROM header, but without L1 latency (that's what the SDK does). Those can be as fast as a single cycle of L2 latency, depending on the game.
  
 ==== SD read request (B9 sd sc sb sa 00 00 00) ==== ==== SD read request (B9 sd sc sb sa 00 00 00) ====
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   * (MSB) sd sc sb sa (LSB) - sector address, in bytes   * (MSB) sd sc sb sa (LSB) - sector address, in bytes
  
-Returns zero when data is ready to access, non-zero if ongoing.+Returns ''0x00000000'' when data is ready to access, ''0x00000001'' if ongoing.
  
 ==== SD read data (BA 00 00 00 00 00 00 00) ==== ==== SD read data (BA 00 00 00 00 00 00 00) ====
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   * (MSB) sd sc sb sa (LSB) - sector address, in bytes   * (MSB) sd sc sb sa (LSB) - sector address, in bytes
  
-Returns zero if done, non-zero if ongoing.+Returns ''0x00000000'' when data is ready to access, ''0x00000001'' if ongoing.
  
 ==== Save write start (BD sd sc sb sa 00 00 00) ==== ==== Save write start (BD sd sc sb sa 00 00 00) ====
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 SD write status, but using the "save" FAT entry table. SD write status, but using the "save" FAT entry table.
  
-==== ROM read decrypted data (BF ?? ?? ?? ?? ?? ?? ??) ====+==== ROM read decrypted data (BF 00 00 00 00 00 00 00) ====
  
 Same as SD read data, but applying a XOR-based obfuscation algorithm to the buffer's contents. Same as SD read data, but applying a XOR-based obfuscation algorithm to the buffer's contents.
notes/flashcart/r4ds.1697466403.txt.gz · Last modified: 2023/10/16 14:26 by asie