Hello, the address lines on VIC-II as used in the C64 are a mix of multiplexed (A0-A5/A8-A13) and static (A7-A11). That's easy enough to explain from the way the memory is set up. But then there is A6 which is, according to the datasheet, multiplexed with a static '1'. From the schematics that doesn't make any sense since it's routed through the 74LS258 just like A7 and as soon as A6 switches to a static '1' the 74LS258 switches too and the 2 address bits supplied by the CIA are valid. Is there a known reason why it was designed that way? Was it maybe used in the CBM-II series in some way? Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-02-16 18:00:03
Archive generated by hypermail 2.2.0.