exstand/yano vs. freewing

seal1

seal1

hello,

wanna built LPT-port interface because wellknown ISA-slot-lessness of modern boards.

I prefer the exstand/yano because it should be faster

yano version

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[EDIT]

yano enhanced exstands (tanishige) interface but at his schematics the caps C2-C6 has really high values 0.1 F ? means 100000 uF ? expensiv ones! 3$ each - gold caps ? no other one are with such high 0.1 F available.

C1 is 10 uF sounds realistic but what kind ? normal electrolyt-cap?

should C2-C6 0.1 uF or 0.1 mF = 100 uF ?

[/EDIT]

anyone has original exstands schematics ?

or a ready built version of extands or even better yanos interface and can look for the values of the caps ?

other problem is: my local dealer got only 74HCTxxx (highspeed cmos ttl) in old big DIP-package.

HC´s (highspeed cmos) only in SMD-package. can I replace the HC with the HCT versions ?
 
HC vs. HCT

according to my research:
  1. pc LPT-port (SPP, PS/2, EPP, ECP) should be TTL
  2. HC (highspeed cmos) chips goes HIGH if input >3.15volt, LOW if input <0.9volt, output according Vcc 2-6v
  3. HCT (highspeed cmos, but with ttl input compatible) chips goes HIGH if input >2v, LOW if input <0.8v, output according Vcc 2-6v
  4. TTL chips output is 2.7v (even Vcc is 5v)

So for my logic: 1 + 4 + 2 -> yano´s interface with HC will not work, coz HC switches only to HIGH if at least 3.15v at inputs but pc-lpt-port (ttl) outputs only 2.7v.

but I assume it works so pc-lpt-port (and sega) must provide CMOS not TTL ?!

replacing HC with HCT ?

HIGH CMOS > HIGH TTL so HCT is ok.

LOW TTL < LOW CMOS, so if pc-lpt-port (or sega) goes LOW within range 0.8-0.9v this is a problem coz HCT dosn´t switch, HCT inputs must <0.8v for LOW ? hope pc-lpt-port/sega are not in this bad range for LOW so replacing HC with HCT works.
 
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