Re: MAX Machine PLA equations

From: smf <*smf_at_null.net*> Date: Sat, 6 Aug 2016 19:09:06 +0100 Message-ID: <ef432e08-b8b1-cdf9-9146-8c34204d7ff4@null.net> · smf_at_null.net

On 06/08/2016 18:13, Francesco Messineo wrote:
> afair, TTL (and NMOS too) floating inputs always go to "1".
> Back in the pre-CMOS era, it was considered "normal" cost saving to
> left TTL inputs floating
> to make a logic "1" on them.
>

That sounds like a pull up (or down) resistor (whether it's internal or 
external) more than floating inputs being reliably 0 or 1.

On the c64 the upper two bits come from the cia, but they must only be 
put on the bus when the vic is doing a read. Is there definitely not 
something similar happening?

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