Posted By
SVS
on 2019-10-09
12:28:31
 |  Expansion port pin
A simple question: pin B of the expansion port is C1LOW or /C1LOW (negate)?
Over zimmer.net I see that, for a typo, there are both these descriptions.
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Posted By
gerliczer
on 2019-10-09
13:14:44
| Re: Expansion port pin
Most, if not all, control signals are low active as the system is designed with NMOS ICs. C1 Low should be too.
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Posted By
MCes
on 2019-10-09
13:17:47
 | Re: Expansion port pin
it's /C1LOW (when it's "0" indicte an C1LOW access)
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Posted By
MCes
on 2019-10-10
09:13:02
| Re: Expansion port pin
@SVS
Don't make confusion: "LOW" and "HIGH" are not referred to the logic level, but at which slice of memory maps they are representing...
Historically each "selecting line" is always (normally) active on low logic level, than it can be directly connected to /CS of the relative ROM chip:
ROM can be internal (function low, function high, basic, kernal) or external (Roms inside the cartridge as games or SW tools..).
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