W78LE812 datasheet(12/25 Pages) WINBOND

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W78LE812

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ON-CHIP MTP ROM CHARACTERISTICS

The W78LE812 has several modes to program the on-chip MTP-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 MTP 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.

PROGRAM VERIFY OPERATION

All the programming data must be checked after program operations. This operation should be

performed after each byte is programmed; it will ensure a substantial program margin.

ERASE OPERATION

An erase operation is the only way to change data from 0 to 1. This operation will erase all the MTP

ROM cells and the security bits from 0 to 1. This erase operation is done when the VPP is reach to

VEP level, CE set to low, and OE set to high.

ERASE VERIFY OPERATION

After an erase operation, all of the bytes in the chip must be verified to check whether they have been

successfully erased to 1 or not. The erase verify operation automatically ensures a substantial erase

margin. This operation will be done after the erase operation if VPP = VEP(14.5V), CE is high and OE

is low.

PROGRAM/ERASE INHIBIT OPERATION

This operation allows parallel erasing or programming of multiple chips with different data. When

P3.6( CE ) = VIH, P3.7( OE ) = VIH, erasing or programming of non-targeted chips is inhibited. So,

except for the P3.6 and P3.7 pins, the individual chips may have common inputs.

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