Reminds me of the 90's when I started sketching out a DMA cart for the C64 using a PC parallel port and a load of 74LS (buffers for the address and data & then something more clever that waited for the bus to be available before firing everything). Unfortunately it's lost to time now (or fortunately because it saves my embarassment). I'm not aware of a decent remote debugger for a real c64 still. On 12/06/2018 06:35, Jim Brain wrote: > 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 > > >Received on 2018-06-12 20:04:01
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