brian@wolves.uucp (Brian Daniels) (07/29/90)
I am putting my motherboard into a new case this week, and was wondering if
you can safely use ribbon cable to extend the ST's cartridge port. Also,
could you get away with making an extension cable that had more than one
cartridge connector on it, with a switch to choose which one to power?
Thanks in advance,
Brian Daniels
--
------------------------------------------------------------------------
"posess yourself--or somebody else will
review yourself--you might find you're someone else"
the FIXX
Brian Daniels
(brian@wolves)
--------------------------------------------------------------------------hase@netmbx.UUCP (Hartmut Semken) (08/03/90)
brian@wolves.uucp (Brian Daniels) writes: >I am putting my motherboard into a new case this week, and was wondering if >you can safely use ribbon cable to extend the ST's cartridge port. Also, Yes, but if You get problems accessing cartridges over the cable, use some drivers (74ALS244 for example). All lines on the cartridge port are unidirectional, so there should be no problem. >could you get away with making an extension cable that had more than one >cartridge connector on it, with a switch to choose which one to power? No. Most cartridges will contain just EPROMs - that's what the cartridge port is for. Most EPROMs are rated to input voltages (adress and data lines) from 0 V to Vcc+0.5 V. If You switch off power for one cartridge, the EPROMs will see input voltages of Vcc+5 Volts. Thats too much (some CMOS EPROMs will than take the 5 Volts from the -CS line as power source and go off when selected...) It's probably safe to use pullups (say 100 kOhms) for the four select lines on every cartridge, open drain drivers for the select lines and a switch to select, which cartridge will get the select. hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP Hi! (Zaphod Beeblebrox)