Keith
The uPD765 FDC chips are still easily obtainable at affordable prices: £5.99 for one, £9.50 for two (£4.75 each), or £15.75 for 5 (£3.15/unit).
The FE2100 is less so, at £22.58 plus postage from Germany.
I suspect there were many more advanced PC support chipsets made, but is it worth the effort of developing a new card for obsolete chips and obsolete media?
Until recently, I only had a grey photograph from a catalogue, but recently an Interak enthusiast acquired some STEbus boards and I shall now be able to photograph them and read the PAL chips. More for posterity than practical need.
A quick look at the board shows most of the circuit follows the data sheet example. The STEbus interface uses a 74LS30 to detect the I/O address, fixed at 3F0 to 3F7. The PAL16R4 uses its combinatorial outputs to generate the /IOR, /IOW and /CS signals to the FE2100 chip. The registered outputs will be some sort of counter or shift register to regulate the timing.
EtchedPixels