ACE34AC04

4K I

VER 1.1

15

(C)

Read RSWP

The Read RSWP command allows the ability to check a quadrant’s write protection status. To find

out if the software write protection has been set to a specific quadrant, the same procedure that was

used to set the quadrant’s write protection can be utilized except that the R/W select bit is set to a

Logic 1, and the A0 pin is not required to have VHV. The Read RSWP sequence requires sending a

control byte of „0110MMM1

‟ (where the „M‟ represents the memory quadrant identifier for the

quadrant to be read) with the R/W bit set to a Logic 1 .If the RSWP has not been set, then the

ACE34AC04 responds to the control byte with an ACK. If the RSWP has been set, the ACE34AC04

responds with a NACK. In either case, both Word Address and Data Word bytes will not be

acknowledged. The operation is completed by the Master creating a Stop Condition.

Table 7: Acknowledge When Reading Protection Status

Quadrant

Status

Instruction

Sent

Instruction

Response

Word

Address

Sent

Word

Address

Response

Data Word

Sent

Data Word

Response

Write

Protected

Read RSWP

NACK

Don’t Care

NACK

Don’t Care

NACK

Not

Protected

Read RSWP

ACK

Don’t Care

NACK

Don’t Care

NACK

Table 8: Read RSWP

Function

Pin

Control Byte

Device Type Identifier

Memory Quadrant Identifier

R/ W

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Set RSWP,

Quadrant 0

X

X

0,1

or

V

HV

0

1

1

0

0

0

1

1

Set RSWP,

Quadrant 1

X

X

1

0

0

1

Set RSWP,

Quadrant 2

X

X

1

0

1

1

Set RSWP,

Quadrant 3

X

X

0

0

0

1