smf wrote: > On 27/07/2018 04:03, Mia Magnusson wrote: >> ... and then someone moves chargen v.s. video ram around and the >> emulation can't really know which pokes were supposed to go to a >> pre buffered screen ram v.s. chargen. > > I believe the VIC20 can only have video ram & chargen in 4k of the > internal ram. > The VIC-I chip can address 16K, but only internal memory, not on the cartridge bus. Normally the operating system nearly all of the lower 1K, but in certain demos like e.g. VIMM and VIMMII, Albert of Pu-239 stored the video matrix in that area in order to use all of the 4K for bitmap. (The unexpanded VIC-20 has 5.5K RAM in total of which 3.5K is available to the user) Some individuals have installed internal 3K expansion to their VIC-20 by piggybacking chips. It is highly non-standard, but allows the VIC-I chip to access that memory as well. I suppose in theory one could install internal 8K expansion and access that memory for the VIC-I chip as well but I don't know anyone who has done it. Best regards Anders CarlssonReceived on 2018-07-27 12:00:05
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