Re: CBM2 v9958 Hires-Color Graphics Card

From: vossi <vossi_at_ceffy.de>
Date: Fri, 1 Feb 2019 01:54:52 -0600 (CST)
Message-ID: <1549007692857-0.post@n4.nabble.com>
Hi,
thanks Segher for the hint to the mcs6500 hardware manual. 
I have it at home, but I never watched the addressing-cycles at the A-pages
;)

The read before write is a normal (short) read-cycle, Andre - about 320ns at
2MHz incl. the decoding logic in the 610.

RAM/ROM or mos IO chips doesn't matter about that none sense read.
But the V9938/58 increases mostly the VRAM addresscounter at this access...

I have an easy solution:
I split the write and read operations with A2.
So I have D900-D903 for write and D904-D907 for read.
A small 16V8 encodes now the CSW/CSR fro the VDP instead of the 7400.

Thanks
Christian



-----
greets
Christian
--
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Received on 2019-02-01 09:00:31

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