W77L32 Datasheet, PDF (66/76 Pages) Winbond – 8-BIT MICROCONTROLLER

W77L32/W77L032A/W77M032A
Examples of Timed Assessing are shown below.
Example 1: Valid access
MOV TA, #0AAh 3 M/C
MOV TA, #055h
3 M/C
MOV WDCON, #00h 3 M/C
Example 2: Valid access
MOV TA, #0AAh
MOV TA, #055h
NOP
SETB EWT
3 M/C
3 M/C
1 M/C
2 M/C
Example 3: Invalid access
MOV TA, #0AAh
MOV TA, #055h
NOP
NOP
CLR POR
3 M/C
3 M/C
1 M/C
1 M/C
2 M/C
Example 4: Invalid Access
MOV TA, #0AAh
NOP
MOV TA, #055h
SETB EWT
3 M/C
1 M/C
3 M/C
2 M/C
Note: M/C = Machine Cycles
In the first two examples, the writing to the protected bits is done before the 3 machine cycle window
closes. In Example 3, however, the writing to the protected bit occurs after the window has closed, and
so there is effectively no change in the status of the protected bit. In Example 4, the second write to TA
occurs 4 machine cycles after the first write, therefore the timed access window in not opened at all,
and the write to the protected bit fails.
12. ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
CONDITION
RATING
UNIT
DC Power Supply
VDD − VSS
-0.3
+7.0
V
Input Voltage
VIN
VSS -0.3
VDD +0.3
V
Operating Temperature
TA
0
+70
°C
Storage Temperatute
Tst
-55
+150
°C
Note: Exposure to conditions beyond those listed under Absolute Maximum Ratings may adversely affect the life and reliability
of the device.
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