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6 flash eprom timing diagrams and parameters, 6 flash eprom timing diagrams and parameters -24, Flash write timing diagram (2 writes) -24 – Intel STRONGARM SA-1100 User Manual

Page 138: Flash eprom timing diagrams and parameters

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10-24

SA-1100

Developer’s Manual

Memory and PCMCIA Control Module

10.4.6

FLASH EPROM Timing Diagrams and Parameters

Flash reads have the same timing as nonburst ROMs as shown in the preceding figures.

Figure 10-10

shows the timing for Flash writes.

In

Figure 10-10

, some of the parameters are defined as follows:

tAS = Address setup to nCS = 1 CPU cycle
tCES = nCS setup to nWE = 2 memory clock cycles (4 CPU cycles)
tASW = Address setup to nWE low (asserted) = 2-1/2 memory cycles (5 CPU cycles)
tDSWH = Write data setup to nWE high (deasserted) = 1/2 memory cycle + (RDN+1) memory cycles
tDH = Data hold after nWE high = 1+1/2 memory cycle
tCEH = nCS held asserted after nWE deasserted = 1 memory clock cycle (2 CPU cycles)
tAH = Address hold after nWE deasserted = 1+1/2 memory cycle (3 CPU cycles)

Figure 10-10. Flash Write Timing Diagram (2 Writes)

A4787-01

CPU Clock

Memory Clock

A[25:0]

D[31:0]

nWE

nOE

nCS0

RDN+1

(2*RRR)+1

(2*RRR)+1

tAS

tAS

tASW

tCES

tDH

tCES

tCEH

tCEH

tAH

tAH

Write Command

Write Data

Possible Read or Write

tCES

tAS

RDN+1

tDSWH

A0

CMD

DATA