DMA successes with Verilog

From: Jim Brain <brain_at_jbrain.com>
Date: Tue, 12 Jun 2018 00:35:33 -0500
Message-ID: <b2e990a0-d9dc-a580-ebd2-6eee25dacf3d@jbrain.com>
I know it's neither new nor terribly interesting to some, but the recent 
Ultimax mode success bolstered my confidence to try a few more complex 
things, like CBM 64 DMA.

I've been impressed by the flexibility of the development cart I 
designed, as it required no more work to set up for DMA tests.

I started off my trying to DMA one byte (to address $8000), and when 
that worked, I then tried 256 bytes.  I hit a snag when trying to store 
a user defined length and had to reimplement the code to use a state 
machine.

But, I have managed to get 1-256 bytes (user defined) to DMA from the 
cart to the 64.

It's a small victory, but I always felt the DMA mode was a mystery in 
implementation details.

Jim



-- 
Jim Brain
brain@jbrain.com  
www.jbrain.com
Received on 2018-06-12 08:00:04

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