
ST92F124/F150/F250 - EXTERNAL MEMORY INTERFACE (EXTMI)
EXTERNAL MEMORY SIGNALS (Cont’d)
Figure 76. External memory Read/Write with a programmable wait
NO WAIT CYCLE
T1
T2
1 AS WAIT CYCLE
T1
TWA
1 DS WAIT CYCLE
T2
TWD
SYSTEM
CLOCK
AS (MC=0)
ALE (MC=1)
(AS pin)
P1, P9
ADDRESS
AS STRETCH
ADDRESS
DS STRETCH
TAVQV
DS (MC=0)
P0
ADDRESS
DATA IN
ADDRESS
DATA IN
RW (MC=0)
OEN (MC=1)
(DS pin)
WEN (MC=1)
(RW pin)
P0
ADDRESS
DATA OUT
RW (MC=0)
OEN (MC=1)
(DS pin)
WEN (MC=1)
(RW pin)
ADDRESS
DATA
TAVWH
TAVWL
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