16 Kbyte Cmos Ram For C64

EE September 1987 16 KBYTE CMOS RAM FOR C64 by P Verhoosel A non-volatile block of RAM or pseudo-ROM for plugging into the Commodore 64"s expansion slot. The expansion port at the rear of the Commodore 64 micro- computer is a 44-pin (22 +22) female edge connector. The ex- pansion slot-also referred to as bus, cartridge or module port- enables plugging in extension modules that require direct ac- cess to the address bus, data bus, and a number of control lines, of the Type 6510 CPU and its support chips inside the computer. Because of this direct connection, due care should be taken not to damage the system by inappropriate connections, overloads, or short-circuits. The signal func- tions and pin assignment of the expansion port are shown in Table 1 and Fig. 1 respectively. Viewed from the computer"s keyboard, and counting from the left to the right, pins 1-22 in- clusive form the upper row, and pins A-Z inclusive the lower row. Notice that letters G, I, 0 and Q are not used. C...