Andrew Gale wrote: > Since there are 9 columns of 8 rows, that's be a 17 way ribbon cable > (i.e. 1.7" wide). I think using 74LS148 or 74LS147 could reduce 9 columns to 4 wires. And 2 more must be added as power for decoders.
This gives 14. The 8 rows can be coded by 74LS151 and decoded by 74LS259 what reduces required wires to 4. As result we have 10 wires round cable which can be 2m long because of amplifiers. This is theory, I didn't try yet. > I was thinking of desoldering the two keyboard connectors from > the pcb and putting a 25way D socket in - using the 12 pin row > to replace the 8-way connector, and the 13 pin row for the 9-way > connector. How do you want to wire the D-Sub DB25 connector? Male or female? Let's make any standard for this. With power signals, LED control and beeper(s?). DB25 could be mistaken with RS232 or Centronics connector. Isn't better to use D-Sub DB23 male (at SAM-pcb side)??? RS232 signal voltage can damage ASIC! > The only thing is: we've now got to hunt around for those disc drive > blanking plates to fill the holes! I'm going to exchange "SAM Drive" to ordinary PC drive. I don't have the best opinion about "SAM Drive" mechanics. The 1770 controller with ordinary PC drive doesn't want to read disks saved on "SAM Drive" (has troubles with some sectors). -- Yarek.
