Saturn Backup Memory Cartridge, 670-6415A

[RDC]

The Sega Saturn Backup Memory cartridge, 670-6415A. It's only used for game saves, versus saving them on the smaller internal memory of the Saturn, that can be lost if the power is removed and the internal battery dies. This Backup Memory cart is flash based, so the saves stay intact when the power is removed, and it has over 17 times the save space versus the internal memory.

TOP


BOTTOM


TOP CLEAN


SCHEMATIC



IC1 - AT29C040A 15TC (150ns)
IC2 - 74HC00A
IC3 - 74HC244A
CE1 - 16v, 47uF
C1, C2, C3 - Decoupling, could be anything from 0.01uF to 1uF each

IC1 must be an AT29C040A (150ns or faster) or the Saturn will not recognize it. It also seems to need to have the Boot Block data present, as I had issues getting another 29C040A 12TC (120ns) to work correctly (Saturn would detect it, but not Clear it) until it was flashed with a dump of the original 29C040A chip. I went thru a fiasco with some rebranded 29LV040A chips (branded as 29C040A) that would not work even with the correct Boot Block Data on them. The Saturn seems to check the Device Code of the chip before proceeding, and since the 29LV is 0xC4 and the 29C is 0xA4, it would have none of that.

Code: [Select]

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000010 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000020 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000030 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000040 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000050 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000060 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000070 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000080 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000090 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000A0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000B0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000C0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000D0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000E0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
000000F0 42 61 63 6B 55 70 52 61 6D 20 46 6F 72 6D 61 74  BackUpRam Format
00000100 00 00 00 00 00 00 00 00 00 00 04 00 00 00 00 00  BackUpRam Format

I've also designed a smaller PCB of this, though not quite small enough for the cartridge flap to close when it's inserted, but for it's intended purpose it doesn't need to.