Page 66 Epson Research and Development
Vancouver Design Center
S1D13505 Hardware Functional Specification
X23A-A-001-14 Issue Date: 01/02/02
7.3.2 EDO-DRAM CAS Before RAS Refresh Timing
Figure 7-16: EDO-DRAM CAS Before RAS Refresh Timing
Table 7-16: EDO-DRAM CAS Before RAS Refresh Timing
Symbol Parameter Min Max Units
t1 Internal memory clock period 25 ns
t2
RAS# precharge time (REG[22h] bits 3-2 = 00) 2t1 - 3 ns
RAS# precharge time (REG[22h] bits 3-2 = 01) 1.45t1 - 3 ns
RAS# precharge time (REG[22h] bits 3-2 = 10) 1t1 - 3 ns
t3
RAS# pulse width (REG[22h] bit 6-5 = 00 and bits 3-2
= 00) 3 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 00 and bits 3-2
= 01) 3.45 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 00 and bits 3-2
= 10) 4 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 01 and bits 3-2
= 00) 2 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 01 and bits 3-2
= 01) 2.45 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 01 and bits 3-2
= 10) 3 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 10 and bits 3-2
= 00) 1 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 10 and bits 3-2
= 01) 1.45 t1 - 3 ns
RAS# pulse width (REG[22h] bit 6-5 = 10 and bits 3-2
= 10) 2 t1 - 3 ns
t4 CAS# pulse width t2 ns
t5 CAS# setup time (REG[22h] bits 3-2 = 00 or 10) 0.45 t1 - 3 ns
CAS# setup time (REG[22h] bits 3-2 = 01) 1 t1 - 3 ns
RAS#
CAS#
t2 t3
t1
Memory
Clock
t4 t5 t6