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picocomputer / rp6502

Picocomputer 6502 firmware
BSD 3-Clause "New" or "Revised" License
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How is other IO besides the VIA mapped? #55

Closed cbmeeks closed 1 month ago

cbmeeks commented 2 months ago

I've been studying the schematic and, correct me if I'm wrong, it would seem the VIA would be turned on with the following addresses:

FF00 to FFE0.

It is only setting pins A15:A5 does the VIA turn off. Meaning, if IORQ = ON and RREQ = OFF, then the VIA is enabled.

How would, for example, another VIA be selected with that memory map?

VIA IS ON

image

VIA IS OFF

image

Thanks

rumbledethumps commented 1 month ago

What "other VIAs" are you trying to select? There's only one in the reference design.

cbmeeks commented 1 month ago

I mean if I wanted to add another VIA or some other IC.

rumbledethumps commented 1 month ago

There's only one VIA in the reference design. This is working as intended. If you want to design something else then you have to do the engineering.

cbmeeks commented 1 month ago

I think you are getting too hung up on "the other via". My point was if I wanted to add other IC's to the design in addition to the existing via. It doesn't seem possible with this design.

But ok....lol