ocr: THE MEMORY MANAGEMENT UNIT (Continued) Bit 6 tunctions as a RAM bank pointer for VIC. It is used to drive CASO low when set low or CAS1 low when set high, thus selecting either RAM bank 0 or RAM bank 1 for the VIC, independently from the processor bank. When in 2 MHz mode the 80-column chip takes over, causing the VIC to be disabled. This disabling is affected by the VIC chip itself holding AEC constantly high, and thus is not directly effected by actions of the MMU. Note that since a VIC cycle is detected by AEC low, that any DMA will put the MMU into VIC configuration, as it too brings AEC l ...
