Re: Building a 6502 peripheral - timing

On 3/14/2018 5:59 PM, Mia Magnusson wrote:
>
> Somewhere on the net I've seen schematics of using 16550 UART's on a
> C64. Although the 6510 differs slightly from a 6502, it could probably
> be used as some kind of guide.
16550 is easy (Intel bus interface)

~WR = !(!(R/!W) * PHI2)
~RD = !(R/!W * PHI2)

Obviously, depending on your choice of logic, you can reduce that down, 
but the gist is there.

64NIC and other options implement the above.
>
As to the general question, I have sigrok here with the LWLA1034, and I 
could run a timing pull of the various signals through some steady state 
timing period, to show the relationships, when I next test the 6509 
emu.  But, I'd want someone to consider where to pull the signals and 
work with me.  If I have to spend lots of cycles trying to determine 
where to test signals, it's likely to not happen.

Jim

-- 
Jim Brain
brain@jbrain.com
www.jbrain.com