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SUBOR Cartridges

Page history last edited by David Dahl 9 years, 10 months ago Saved with comment

Bust open your SUBOR Catridges and Start Hacking!


We have discovered two types of flash cartridges shipped with the SUBOR.  Earlier models came with SST28VF040 and newer models (shipped from Maked Shed) appear to have come shipped with AMD.   This page has ROM dumps from both.


The fact that they are flash cartridges is very important to the project, because it means we can reprogram or augment existing cartridges to put educational, learning, and musical software.  Learn the times table via SUBOR, anyone?  The greek alphabet song?


We are collecting ROM Dumps of SUBOR catridges using homebrewed cartridge adaptors in order learn how to program them.

If you are very intrepid, built a Flash Interface and help us figure out how to write to the cartridges from another computer!



These connectors are useful for building SUBOR interface boards:


DigiKey Part Number for a female 60-pin Cartridge socket/Card Edge Connector (0.100" pitch, 0.050"-0.075" thick)  $3.48







Atmega32 breadboard Flash Interface









Mapping for Atmega32 Dev Cart:


A0-A7 -> PORTA

A8-A15 -> PORTB

A16-A18 -> PORTD[4:2]

D0-D7 -> PORTC




Atmega128 dev board Flash Interface



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Flash Images




SSTV8F040 Stock Image Cartridge (SB-LC-4.0)

These images consist of 2048 sectors of 256 bytes each.


ASCII Versions   flash.txt  suborflash2.txt  suborflash4.txt 


binary version: flash.bin


Strings contained within flash.bin: strings.txt


visualization of contents: 



AMD Cartridge Stock Image (SB-LC-5.0)


AM29F040-120EC, which has the same pinout as the SST part, except that it is arranged as 16 banks of size 32kB.

Binary Image - http://nomen.nfshost.com/ppower/suborcart0.zip





Cartridge Pinout and Commentary




Judging from these pictures, we thought it looks like the Write Enable pin WE# of the Flash chip is connected to the bus.  This would imply being able to write to the SUBOR Flash chip.  However, investigation has shown that WE# is connected to Vcc, meaning it's impossible to tell the flash chip to write. 


No Carrier has suggested that it might be "possible to wire it up to the R/W  signal on the cart edge, should check how the SRAM is connected."


Dave: As for pin 7 of the flash being connected to VCC, it might still be possible to do a simple modification to the cart to allow writing.

The modification would entail cutting a trace going to pin7 and installing a toggle switch between pin 7 and switching between VCC (normal operation) and one of the unused pins on the edge connector.  A low-cost microcontroller board could be used as a programmer. 



Q: Can someone confirm the trace between pin 7 of Flash and pin 14 or 47 of SUBOR Card Edge Connector? 


A: Edge connector pins 14 and 47 don't appear to be connected to the flash chip. (Pin 14 connects to the SRAM pin 27 (/WE), and 47 has no traces routed to it at all on my cart.)    (Thanks, Dave!)


Q: How is the SRAM connected?


A: SRAM is connected similar the Flash, with the major exception being that the write enable is connected to XRW to enable writing, and chip enable high is connected to XVA9 to enable RAM in the upper half of the cartridge memory space.


Note, Famicom signals CHR D0-D7 are not used by SUBOR.  This goes along with the VT02 Data Sheet which states that it is able to operate in "single bus mode."  This means that both program and graphics fetches share the same address space using one set of address and data buses, unlike the Famicom which has two separate bus sets for program and graphics.






Data Sheets



Device Driver for SST Flash Memory Chip on SUBOR Cartridges: 

SST29VF040.asm  Currently, it's half in C and half in 0x86 Assembly. 

Could we have a volunteer to translate it into pure C, or 6502 Assembly?


  • Data Sheet for SRAM Chip on SUBOR Cartridges:               BR6265.pdf 



Pinout for Famicom Cartridge, believed to be the same as the SUBOR: NES_Famicom_Pinouts.pdf











Comments (1)

Derek Lomas said

at 8:44 pm on Dec 8, 2009

This is amazing stuff. Beautiful

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