RAM/EPROM card for the Z80

tAM/EPROM card for the Z80 elektor may 1982 —5-51 Memory cards are basically birds of a feather. They all contain memory ICs, BUS buffers and a control circuit. The latter, however, does tend to vary from one system to another. The RAM/ EPROM card described in the September "80 issue was originally designed for use with the SC/MP and 6502 systems, but after a couple of alterations it can be run on the Z80 as welf. This involves changing the printed circuit board by breaking 9 tracks and then inserting 7 new wire links. No new components are required. In other words, it is just a "cut and shunt" exercise. Figures 1 and 2 show the changes that need to be made to the lower and com- ponent overlay sides of the printed circuit board, respectively. As can be seen, very little cutting and linking is required. memory access and refresh cycles. During normal memory access the CPU starts by outputting addresses. After a short period, the MREQ signal is gener- ated. This is accompanied by ...