keithAfter years of work, the GAL16V8 replacement equations for the Expansion Systems DataFlyer 500 are public: github.com/keithgh1/df500re
The DataFlyer 500 is a side-expansion SCSI/IDE hard disk controller for the Amiga 500. Its glue logic lives in security-locked TIBPAL16L8 chips that can’t be read, and when one of them dies, the card dies with it. These files let you burn a GAL16V8 that drops straight into the original socket.
What’s in the repo:
- BUSS for SCSI-only boards, PCB rev 2.0
- BUSS for SCSI-only boards, PCB rev 2.1
- DFI and DTACK02 for IDE-only boards, PCB rev 2.3
Each one comes as CUPL source (.pld) and a ready-to-burn JEDEC file (.jed), with fuse checksums. The board revisions carry different programs, so pick by the PCB revision printed on your board and the label on the chip you’re replacing. The README has a table and a photo showing where to look.
Every image was checked against an original chip on a microcontroller test harness, hundreds of thousands of test vectors with zero mismatches, and the burned GALs boot real cards. My IDE board now runs with no original PALs at all.
The README also walks through how it was done: sending chips to Rhine Labs (unreadable even on industrial programmers), recreating the board in KiCad, disassembling the boot ROM, logic analyzer traces of the live system, a GAL verifier PCB, and a lot of trial and error. A full write-up will follow.
Thanks to Walter, who traced the rev 2.0 board’s pinout and proved the image on his own card.
Released under the MIT license. If you own a combined SCSI + IDE DataFlyer (BUSS-socket chip labeled DFSI), I’d love to hear from you. It’s the one variant still uncovered.
Add comment