Draw the logic symbol for the TMS4256, which is a 256K * 1 DRAM. How many pins are saved by using address multiplexing for this DRAM?
Figure 12-46(a) shows a circuit that generates the RAS, CAS, and MUX signals needed for proper operation of the circuit of Figure 12-27(b). The 10-MHz master clock signal provides the basic timing for the computer. The memory request signal (MEMR) is generated by the CPU in synchronism with the master clock, as shown in part (b) of the figure. MEMR is normally LOW and is driven HIGH whenever the CPU wants to access memory for a read or a write operation. Determine the waveforms at Q0, Q1, and Q2, and compare them with the desired waveforms of Figure 12-28.