[AP2071AEN]

MS1607-E-00

- 21 -

2014/03

2. READ Operations

Set the R/W bit = “1” for the READ operation of the AP2071AEN. The master can read the next address’s data

by generating an acknowledge instead of terminating the write cycle after the receipt of the first data word.

After receiving each data packet the internal 5-bit address counter is incremented, and the next data is

automatically taken into the next address. If the address exceeds 08H prior to generating stop condition, the

address counter will “roll over” to 00H and the previous data will be overwritten.

The AP2071AEN supports one basic read operation: Random Address Read.

2-1. Random Address Read

The random read operation allows the master to access any memory location at random. Prior to issuing the

slave address with the R/W bit “1”, the master must first perform a “dummy” write operation. The master

issues start request, a slave address (R/W bit = “0”) and then the register address to read. After the register

address is acknowledged, the master immediately reissues the start request and the slave address with the R/W

bit “1”. The AP2071AEN then generates an acknowledge, 1 byte of data and increments the internal address

counter by 1. If the master does not generate an acknowledge to the data but generates a stop condition, the

AP2071AEN ceases transmission.

SDA

Slave

Address

S

S

T

A

R

T

R/W="0"

A

C

K

A

C

K

A

C

K

Data(n)

A

C

K

Data(n+x)

A

C

K

P

S

T

O

P

Sub

Address(n)

S

Slave

Address

R/W="1"

S

T

A

R

T

Data(n+1)

A

C

K

N

A

C

K

M

A

S

T

E

R

M

A

S

T

E

R

M

A

S

T

E

R

M

A

S

T

E

R

Figure 13. Random Address Read