AP2061 Datasheet, PDF (15/24 Pages) Asahi Kasei Microsystems – 2.0A High-side LED Driver for Camera Flash with I2C

CONFIDENTIAL
[AP2061]
2. READ Operations
Set the R/W bit = “1” for the READ operation of the AP2061. 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 04H prior to generating stop condition, the address counter will “roll over” to 00H and the previous data
will be overwritten.
The AP2061 supports two basic read operations: 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 AP2061 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 AP2061 ceases transmission.
S
T
A
R/W ="0"
R
T
SDA
Slave
S _Address
Sub
Address(n)
A
C
K
S
T
A
R/W="1"
R
T
Slave
S _Address
A
A
C
C
K
K
Data(n)
Data(n+1)
MA
MA
AC
S
T
K
A
S
T
C
K
E
E
R
R
S
T
O
P
Data(n+x)
P
MA
MN
A
S
T
C
K
A
S
T
A
C
E
EK
R
R
Figure 12. RANDOM ADDRESS READ
SDA
SCL
S
start condition
P
stop condition
Figure 13. START and STOP Conditions
Rev. 0.1
- 15 -
2012/10