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SS1102C Special Modes
102
PRELIMINARY V1.8
Figure 38.
External Instruction Fetch From Program Memory
16.4.
EXTERNAL MEMORY MODE
The SS1102C is designed to be used in a 48 pin package with internal program and data
memory. For test purposes the chip can be put into external memory mode such that
external programs and data may be accessed to test the device. This mode is entered by
driving the TST pin high with P4.3 and P4.2 low during reset. After reset P4.3 will
become the PSEN output and P4.2 will become the ALE output. The remaining pin
functions are listed below along with timing diagrams.
PIN
TYPE
FUNCTION
P07-0/AD7-0
I/O
Lower address and data
P27-0/A15-8
OUTPUT
Upper address output
P3.6/NWR
OUTPUT
Data memory write
State 4
State 5
State 6
State 1
State 2
State 3
NX1
Address 15-8 out
Address 15-8 out
EPSEN
EA15-8
Data In
XD7-0
Address 7-0 out
Address 7-0 out
EAD7-0
Data In
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