Card hardware: Difference between revisions

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+= DSi cards =
+There are essentially 3 different types of DS/DSi cards:
+* Nitro (DS)
+* Hybrid (DS & DSi)
+* Limited (DSi only)
+For Nitro cards, DSi enters backward compatibility mode to ensure an environment similar to an old DS (no cameras, slower clock speed, et cetera).
+For Hybrid cards, the software can make use of DSi features when running on a DSi, while reverting back to DS only features when running on a DS.
+For Limited cards, the software will only run on a DSi, and cannot be run on a DS.
+= Card slot =
+The DSi card slot is exactly the same as the old DS card slot (also known as SLOT-1).
+However, the DSi has more control over this slot in software than its DS counterpart.
+More specifically, the following hardware lines can be controlled (indirectly) in software:
+* Power supply (VCC) can be enabled or disabled
+* Reset (RST) can be cycled
+Being able to reset a card using the hardware RST line is essential for the DSi card protocol.
+= Card commands =
 Here's a set of sample card commands that an old DS sends to a DSi enhanced card upon bootup:
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 |0000
 |3CA3BD240F4B7400
-| ENTER KEY1
+| ENTER BLOWFISH MODE
 |-
 |09F8
 |400008867A9F4B74
-| ENTER KEY2
+| RESEED LFSR
 |-
 |0914
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 |0200
 |0000000000000000
-| HEADER again?
+| HEADER again
 |-
 |0000
 |3DBA1F0A0E91C100
-| ENTER KEY1 again?
+| ENTER BLOWFISH DSi MODE
 |-
 |09F8
 |67DCFB8E9CC369DF
-| ENTER KEY2 again?
+| RESEED LFSR
 |-
 |0914
 |A1FF8184D5312ACD
-| CARDID again?
+| CARDID again
 |-
 |19B8
 |E1B09DEAABE3D960
-| SEC again?
+| SEC DSi 4
 |-
 |19B8
 |082289FB6F52EC75
-| SEC again?
+| SEC DSi 5
 |-
 |19B8
 |854F68025AAC4B6D
-| SEC again?
+| SEC DSi 6
 |-
 |19B8
 |994FAFFDD8993548
-| SEC again?
+| SEC DSi 7
 |-
 |09F8
 |049D1DB7297CCE7F
-| ENTER MAIN ?
+| ENTER LFSR MODE
 |-
 |0004
 |247D01C82FD0D964
-| CARDID?
+| CARDID again
 |-
 |0200
 |1300E4799B395232
-| ROM READ?
+| ROM READ
 |-
 |0200
 |14C25EC1E7F63C27
-| ROM READ?
+| ROM READ
 |-
 |0200
 |BA11CDA5BDB17489
-| ROM READ?
+| ROM READ
 |}
-The command after 0x3D can not be decrypted using the previous KEY1, it is likely that the Blowfish P and/or S arrays are switched with a new set. The 0x9F8 response for this command is identical to the previous ENTER KEY2 command (which is a fixed stream), so it is also very likely that this command is issueing a new LFSR seed.
+The command after 0x3D can not be decrypted using the old DS blowfish keys, it is likely that new blowfish keys are used when entering DSi blowfish mode. From the response lengths and similarity to the normal DS card protocol, a good guesstimate can be made about what each command in the DSi card protocol does.
-More to come...