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[RETRO Innovations]

On 1/4/2017 12:08 PM, Dave Philipsen wrote:
> Internally there are multiple devices being driven by the address 
> lines.   I have seen many implementations of devices all sitting on 
> the same unbuffered bus of an 8-bit CPU system (usually in a card cage).
The 'fanout' of TTL gates is 10, though CPUs typically are higher, since 
lots of things will connect to address and data lines. Coupled with 
using advanced logic (LSTTL creates 1/10th the load on the line as 
normal TTL, for instance), and you could (and would) see 20 ICs hanging 
on the address and data lines without issue.

Noise is probably the larger issue.  An unbuffered address or data line 
on a cart port is an antenna...

Jim