Motorola MC68VZ328 19.3.9 DRAM Hidden Refresh Cycle (Low-Power Mode)

19-12 MC68VZ328 User’s Manual 
AC Electrical Characteristics
Figure 19-8. DRAM Hidden Refresh Cycle (Normal Mode) Timing Diagram
19.3.9 DRAM Hidden Refresh Cycle (Low-Power Mode)
Figure 19-9 shows the DRAM hidden refresh cycle timin g diagram for low-power mode. The si gnal val ues
and units of measure for this figure are found in Table19-11 on page 19-13. Detailed information about
the operation of individual signals can be found in Chapter7, “DRAM Controller.”
Figure 19-9. DRAM Hidden Refresh Cycle (Low-Power Mode) Timing Diagram
Table 19-10. DRAM Hidden Refresh Cycle (Normal Mode) Timing Parameters
Number Characteristic (3.0 ± 0.3) V Unit
Minimum Maximum
1 CASx pulse width 88 —ns
2 RASx pulse width 88 — ns
3 CASx asserted to RASx asserted 28 32 ns
4 RASx negated to CASx negated -28 — ns
5 CASx negated to next CASx asserted 88 — ns
6DWE
negated before CASx asserted 58 — ns
Note: RASx stands for RAS0 and RAS1. CASx stands for CAS0 and CAS1.
CASx
DWE
RASx
51
23
6
4
CASx
DWE
RASx
1
5
3 4
6 2