Wow I didnt realize it was that many years ago either where do they go. Terry Raymond On Thursday, September 24, 2015, Pasi 'Albert' Ojala <a1bert@iki.fi> wrote: > On 09/24/15 21:48, Anders Carlsson wrote: > >> Pasi Ojala wrote: >> >> However, if the memory were visible to VIC-I >>> >> >> Doesn't it take internal modifications to make any sort of memory >> available to the VIC-I, or can it somehow be achived through the expansion >> bus? >> > Yes, and it was one thing xvic had wrong at some point. > > There is VR/W signal on the expansion port. > > Now, where are the schematics... Here, but where's the cartridge port.. > > Only CA0 to CA15 appear in the cartridge port, not VA0 to VA15. 65245 > buffers allow CA (6502 address) to drive VA (VIC-I address) and it is > strictly one way. The internal RAM is connected to the VA bus. So, VIC-I > can only access internal memory, not any expansion memory. > > Can the VIC-I read from memory connected to I/O blocks 2 and 3 ($9800 - >> $9FFF if I recall correctly) if that memory is connected from the cartridge? >> > VIC-I can't provide the address. Another buffer connects CD (6502 data) > and BD (VIC-I data) buses. This one had direction controlled by CR/W, and > while CR/W is high during video access, VIC-I can't see the data on the CD > bus (cart port). Unless you force the CR/W low from the cartridge port... > > >> I believe the VIC-20 scene in latter years has developed a couple more >> image formats since Pasi's format 15+ years ago, but I believe those are >> even more CPU intensive with increased FLI like colour resolution. >> > Time flies... :D > > -Pasi > > > Message was sent through the cbm-hackers mailing list > -- Sent from Gmail Mobile Message was sent through the cbm-hackers mailing listReceived on 2015-09-25 01:00:07
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