W77IE58 Datasheet, PDF (76/90 Pages) Winbond – 8-BIT MICROCONTROLLER

Preliminary W77IE58
MOV
MOV
MOV
TA, #0AAh 3 M/C
TA, #055h
3 M/C
WDCON, #00h 3 M/C
Note: M/C = Machine Cycles
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
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.
ON-CHIP FLASH ROM CHARACTERISTICS
The W77IE58 has several modes to program the on-chip Flash ROM. All these operations are configured
by the pins RST, ALE, PSEN , A9CTRL(P3.0), A13CTRL(P3.1), A14CTRL(P3.2), OECTRL(P3.3),
CE (P3.6), OE (P3.7), A0(P1.0) and VPP( EA ). Moreover, the A15−A0(P2.7−P2.0, P1.7−P1.0) and the
D7−D0(P0.7−P0.0) serve as the address and data bus respectively for these operations.
Read Operation
This operation is supported for customer to read their code and the Security bits. The data will not be
valid if the Lock bit is programmed to low.
Output Disable Condition
When the OE is set to high, no data output appears on the D7..D0.
Program Operation
This operation is used to program the data to FLASH ROM and the security bits. Program operation is
done when the VPP is reach to VCP (12.5V) level, CE set to low, and OE set to high.
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