ocr: THE PROGRAMMED LOGIC ARRAY FOLD OUT SCHEMATIC SHEET 2, PAGE 74, FOR EASY REFERENCE. The 8721 C128 PLA is a programmed version of the Commodore 48 Pin Programmable Logic Array. It provides all of the chip selects and other decoded signals that were necessary for the C64, along with a number of such signals new in the C128 system. Summary of PLA functions: Control all ROM selects (KERNAL, Z-80, V/O decoding, for Z-80 V/O cycle BASIC, FUNCTION, EXTERNAL) in all and Z-80 memory mapping. operating modes. - Data bus direction signal. VIC chip select. 1/O group chip select (includes 1/0-1, Color RAM ...
