W77C58 Datasheet, PDF (62/71 Pages) Winbond – 8 BIT MICROCONTROLLER

Preliminary W77C58
SETB EWT
Example 3: Invalid access
MOV TA, #0AAh
MOV TA, #055h
NOP
NOP
CLR POR
2 M/C
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
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.
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.
DC CHARACTERISTICS
(VDD−VSS = 5V ±10%, TA = 25°C, Fosc = 20 MHz, unless otherwise specified.)
PARAMETER
SYMBOL
SPECIFICATION
MIN. MAX. UNIT
Operating Voltage
VDD
4.5
5.5
V
Operating Current
IDD
-
50
mA
TEST CONDITIONS
No load
VDD = RST = 5.5V
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