W78LE812

Publication Release Date: February 1999

- 13 -

Revision A2

COMPANY/DEVICE ID READ OPERATION

This operation is supported for MTP ROM programmer to get the company ID or device ID on the

W78LE812.

OPERATIONS

P3.0

(A9

CTRL)

P3.1

(A13

CTRL)

P3.2

(A14

CTRL)

P3.3

(OE

CTRL)

P3.6

P3.7

EA

P2,P1

(A15..A0)

P0

(D7..D0)

NOTES

Read

0

0

0

0

0

0

1

Address

Data Out

Output Disable

0

0

0

0

0

1

1

X

Hi-Z

Program

0

0

0

0

0

1

Address

Data In

Program Verify

0

0

0

0

1

0

Address

Data Out

@3

Erase

1

0

0

0

0

1

A0:0,

others: X

Data In

0FFH

@4

Erase Verify

1

0

0

0

1

0

Address

Data Out

@5

Program/Erase

Inhibit

X

0

0

0

1

1

X

X

Company ID

1

0

0

0

0

0

1

A0 = 0

Data Out

Device ID

1

0

0

0

0

0

1

A0 = 1

Data Out

Notes:

3. The program verify operation follows behind the program operation.

4. This erase operation will erase all the on-chip MTP-ROM cells and the Security bits.

5. The erase verify operation follows behind the erase operation.

SECURITY BITS

During the on-chip MTP-ROM operation mode, the MTP-ROM can be programmed and verified

repeatedly. Until the code inside the MTP-ROM is confirmed OK, the code can be protected. The

protection of MTP ROM and those operations on it are described below.

The W78LE812 has several Special Setting Registers, including the Security Register and

Company/Device ID Registers, which can not be accessed in normal mode. These registers can only

be accessed from the MTP-ROM operation mode. Those bits of the Security Registers can not be

changed once they have been programmed from high to low. They can only be reset through erase-

all operation.

The contents of the Company ID and Device ID registers have been set in factory. Both registers are

addressed by the A0 address line during the same specific condition.

The Security Register is addressed in the MTP-ROM operation mode by address #0FFFFh.