exstand/yano vs. freewing

[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

[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 ?

 

[seal1]

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.

 

[Pinchy]

Should be .1uf decoupling capacitors.

 

[seal1]

Originally posted by Pinchy@Fri, 2005-03-25 @ 02:04 PM

Should be .1uf decoupling capacitors.

[post=132100]Quoted post[/post]​

thx, finally someone answered my monolog ;-)