====== SuperCard (GBA) programming ======

===== All models =====

==== SC_MODE (0x9FFFFFE) ====

To unlock this register, one must write **0xA55A** to it first.

<code>
15       bit       0
 ---- ---- ---- ----
 ???? ???? ???? ?wsm
                 |||
                 ||+- Map registers 
                 |+-- CF/SD enable
                 +--- PSRAM write enable
                      Also swaps SRAM bank (2 x 64 KB)
</code>

===== CompactFlash models =====

For CompactFlash card access, the SuperCard CF mimics [[notes:flashcart:gbamp|the GBA Movie Player interface]].

===== SD models =====

==== SCSD_DATA_WR (0x900000x) ====

SD card 4-bit data bus writes.

<code>
15       bit       0
 ---- ---- ---- ----
 oooo .... .... ....
 ||||
 ++++---------------- Written value.
</code>

==== SCSD_DATA_RD (0x910000x) ====

SD card 4-bit data bus reads.

TODO: Most likely operates as a 16-bit shift register. This means that, to read sixteen bits in order, the address must be accessed four times.

<code>
15       bit       0
 ---- ---- ---- ----
 oooo .... .... ....
 ||||
 ++++---------------- Written value.
</code>

==== SCSD_CMD (0x9800000) ====

SD card 1-bit command bus.

<code>
15       bit       0
 ---- ---- ---- ----
 .... ..?? o... ...i
        || |       |
        || |       +- Input (from card)
        || |
        || +--------- Output (to card)
        ||
        ++----------- Related to card insertion?
</code>

===== SuperCard Lite =====

==== SCLT_ENABLE (0x9440000) ====

===== See also =====

  * [[https://github.com/davidgfnet/supercard-pcb-reverse|SuperCard PCB scans and datasheet archive]]
  * [[https://html-preview.github.io/?url=https://github.com/davidgfnet/gba-supercard-cpld/blob/master/report.html|SuperCard CPLD dump report]]