I saw this adapter for sale on eBay, got it for $4.69 + $5.41 shipping. Why? Because it looked interesting.
Googling and more productively Altavista-ing gave me the following:
This specific FPD is assy 630-0049C, which is not in Gamba's list, so I'm not sure what model it fits. The date makes me think maybe the SE.
folklore.org mentions that Burrell Smith co-founded Radius along with Andy Hertzfield and others. The Full Page Display Card and an Accelerator cars was their first products.
This of course implies that the Full Page Display Card would have quite a few PALs on it.
| 6 | /AS |
| 10 | /DTACK |
| 11 | /BG |
| 13 | /BR |
| 15 | CLK |
| 17 | /HALT |
| 18 | /RESET |
| 20 | E |
| 27 | FC1 |
| 48 | A20 |
The Bus Master requests the use of the 68000's busses by pulling BR low (Bus Request). The 68000 will then pull BG (Bus Grant) low to indicate that it will release control of the busses at the completion of the current cycle. When the Bus Master is ready to take control it will assert BGACK (Bus Grant Acknowledge) as long as BG=0, AS=1 (the 68000 is not using the bus), DTACK=1 (no external devices are using the bus), and BGACK=1 (no other Bus Master is trying to use the bus).
Two 27C256 EPROMS 297-0017-A and 297-0018-A, 128 kbyte dual-port display RAM (4 x 42164), 3 x GAL20V8 (RAD-323-1032A, RAD-323-1038A, RAD-323-1042A), 1 x GAL16V8 (323-1027B), 1 x PLDC20G1O (RAD-323-2031A) which seems to be very similar to a GAL20V8? There's a jumper to change the EPROM to SRAM as well. Interesting.
The socketed PALs all have their security fuses blown.
U18 and U19 are 27C256 EPROMs.
|
|
Back to Wouter's Macintosh Page | (This page last modified 2021-04-19) |
