512K ROM/GROM UBERGROM Cartridge Boards

This cartridge board significantly expands the capabilities of the TI cartridge port by providing up to 512K of ROM memory using a non-inverted 8K bank-switching scheme. This is the opposite of the scheme originally found on the 16K and 64K cartridge boards built by Jon Guidry, as that method could not extend the banking beyond the 128K maximum imposed by the 74LS379 design. The Guidry boards using the 74LS379 do not impose an expected initialization state on the latch outputs, thus requiring header files in each bank to ensure cartridge initialization. The 512K of bank-switched ROM on the the new board uses the 74LS378 and does not require the bank inversion used in prior versions of Jon’s cartridge board, but it still requires the header files in each bank to ensure stable startup. Finally, the board includes a socket for an ATMega 1284 (or 1284P) AVR. Tursi provided code to allow the AVR to be used as 128K of GROM memory space, using up to 16 GROM bases. The combination of these feature changes now allows the board to be used to replicate older ROM/GROM cartridges using 6K or 8K GROMs, with the exception of MBX cartridges, as those would require some additional logic to add 1K of RAM to the board. It is now possible to play some of the unreleased TI titles from a cartridge, as they were originally designed to be used, instead of from disk.

UBER Grom configuration tool: (software at http://www.harmlesslion.com/cgi-bin/onesoft.cgi?118) or select default burn in options...

The UBER Grom in action:

NOTE: 512k flash memory chip no longer included with this purchase. The chip is a AT49F040 flash rom and you can source it at mouser along with the 1284p.

YOU WILL NEED A ATMEL 1284 OR 1284P AVR TO USE THIS BOARD TO IT'S FULL CAPABILITIES. AND A PROGRAMMER CAPABLE OF PROGRAMMING BOTH THE FLASH DEVICE AND THE AVR.

Burn image descriptions:

Xb2.7 includes the XB2.7 suite (pictured below) 32k memory expansion is required for these utilities to work correctly, XB and Ti basic will run fine without 32k.

XB 3 in 1 burn includes TI Extended Basic V2.5, Gazoo's Extended Basic V2.7 and Richard Gilbertson's RXB 2015D, these are selected using the review module library selection. No extra utilities are included. 32k memory expansion is required for REA.

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RXB2015D burn is just the RXB 2015D and REA 2015