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AT88SC1003

2035B–SMEM–08/03

Figure 11. Erase Operation Application Zone 2 (AZ2) EC2 Function Disabled

Note:

A

This diagram illustrates the protocol for setting the E2 flag in Security Level 2 (issuer fuse blown). Erase operations in Security

Level 1 within Application Zone 2 do not require setting of the E2 flag. In Security Level 1, an erase operation on any bit in Appli-

cation Zone 2 will erase the entire zone. EC2EN Fuse = “0” (disabled).

A = Compare sequence of EZ2. If the comparison is valid, the EZ2 flag is set to “1”, enabling erasure of AZ2.

B = If E2 is set to “1”, an erase operation on Bit 768 will erase Bits 480–735 (AZ2).

C = After the falling edge of CLK, the device will drive the I/O contact to the logic state of the existing data in Bit 768. The state

of this bit is not affected by the AZ2 erase operation.

D = After the falling edge of CLK, the address is incremented and the state of the next bit is driven on the I/O contact.

Address

RST

CLK

PGM

Output

Input

Input

Output

Input

I/O

E2 flag

A

0

A

x

A

2

A

1

A

736

A

735

A

737

A

766

A

767

A

768

Reset

D

0

D

1

CD

736

CD

737

CD

767

D

X

1

Read

(B)

(C)

Output

A

769

Read

(D)

(A)

Compare EZ2

Erase

D

768