MAD-1 Pinout: Difference between revisions

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"MAD-1" Stands for "Memory Address Decoder 1". It is used for Memory Mapping / Address Decoding in HiROM and LoROM Cartridges and Controls the Power for Save RAM.
"MAD-1" Stands for "Memory Address Decoder 1". It is used for mapping ROMs, the DSP-n coprocessor, and cart save RAM; as well as providing battery switchover for games with save RAM.


        .---\/---.
            .---\/---.
  /HS <- | 01  16 | -> /LS
  /ROM2CE <- | 01  16 | -> /ROM1CE
/SR <- | 02  15 | <- A15 (LoROM); A13 (HiROM)
  /RAMCE <- | 02  15 | <- A15 (mode $20); A13 (mode $21)
   NC -- | 03  14 | <- PA4 (LoROM); A14 (HiROM)
   /AUXCE <- | 03  14 | <- A20 (mode $20); A14 (mode $21)
/RS <- | 04  13 | <- PA5
  /ROMCE <- | 04  13 | <- A21 (mode $20 or $21); A23 (mode $25)
SVC -- | 05  12 | <- VCC / PA6 (LoROM); A15 / BA6 (HiROM)
  RAMVcc <- | 05  12 | <- A22 (mode $20); A15 or A22 (mode $21)
VCC -- | 06  11 | <- /ROMSEL
    +5V -- | 06  11 | <- /ROMSEL
  BAT -- | 07  10 | <- MSEL
  Battery -> | 07  10 | <- Map
GND -- | 08  09 | <- /RST
    GND -- | 08  09 | <- /Reset
        `--------´
            `--------´


*/HS: When Using 2 ROM Chips, this Selects the Upper One
* /ROM2CE: asserted when pin 13 is high, for using two ROM chips
*/LS: this Selects the Lower One
* /ROM1CE: asserted when pin 13 is low, for using two ROM chips
*MSEL: Connected to GND in LoROM; to VCC in HiROM
* /ROMCE: asserted (low) if either /ROM1CE or /ROM2CE are asserted
*BAT: Voltage from Battery
* Map: changes the five outputs (16, 1-4) to mode $20 (when grounded) or mode $21 (when tied high)
*SVC: Voltage to Save RAM
* Battery: from Battery via a 1k resitor
*/RS: /CS for Save RAM
* RAMVcc: power supply to cart save RAM
*/RS: /CS for ROM Chip
* /RAMCE: asserted to access cart save RAM
*/RST: Reset from Cartridge
* /AUXCE: asserted to access cart auxiliary (only ever seen used with DSP-n coprocessor)
* /Reset: reset signal from card edge

Latest revision as of 08:29, 12 March 2025

"MAD-1" Stands for "Memory Address Decoder 1". It is used for mapping ROMs, the DSP-n coprocessor, and cart save RAM; as well as providing battery switchover for games with save RAM. 

           .---\/---.
/ROM2CE <- | 01  16 | -> /ROM1CE
 /RAMCE <- | 02  15 | <- A15 (mode $20); A13 (mode $21)
 /AUXCE <- | 03  14 | <- A20 (mode $20); A14 (mode $21)
 /ROMCE <- | 04  13 | <- A21 (mode $20 or $21); A23 (mode $25)
 RAMVcc <- | 05  12 | <- A22 (mode $20); A15 or A22 (mode $21)
    +5V -- | 06  11 | <- /ROMSEL
Battery -> | 07  10 | <- Map
    GND -- | 08  09 | <- /Reset
           `--------´
  • /ROM2CE: asserted when pin 13 is high, for using two ROM chips
  • /ROM1CE: asserted when pin 13 is low, for using two ROM chips
  • /ROMCE: asserted (low) if either /ROM1CE or /ROM2CE are asserted
  • Map: changes the five outputs (16, 1-4) to mode $20 (when grounded) or mode $21 (when tied high)
  • Battery: from Battery via a 1k resitor
  • RAMVcc: power supply to cart save RAM
  • /RAMCE: asserted to access cart save RAM
  • /AUXCE: asserted to access cart auxiliary (only ever seen used with DSP-n coprocessor)
  • /Reset: reset signal from card edge
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