SegaXtreme

exstand/yano vs. freewing

seal1 - Mar 24, 2005

		seal1		Mar 24, 2005
			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		Mar 25, 2005
			HC vs. HCT according to my research: pc LPT-port (SPP, PS/2, EPP, ECP) should be TTL HC (highspeed cmos) chips goes HIGH if input >3.15volt, LOW if input <0.9volt, output according Vcc 2-6v HCT (highspeed cmos, but with ttl input compatible) chips goes HIGH if input >2v, LOW if input <0.8v, output according Vcc 2-6v 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		Mar 25, 2005
			Should be .1uf decoupling capacitors.

seal1

Mar 25, 2005

	
	
		
		
			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 ;-)