PAS109B Datasheet, PDF (8/15 Pages) Pixart Imaging Inc. – PAS109BC QQVGA COLOR CMOS IMAGE SENSOR PAS109BB QQVGA MONO CMOS IMAGE SENSOR

PixArt Imaging Inc.
PAS109B
CMOS Image Sensor IC
5.2.2 Slave transmits data to master (read cycle)
ƒThe sub-address was taken from previous write cycle
ƒThe sub-address is automatically increment after each byte read
ƒAm : Acknowledge by master
ƒNote there is no acknowledgment from master after last byte read
1ST BYTE
S
SLAVE ADDRESS
(7 BITS)
RW A
2ND BYTE
DATA (8 BIT)
n BYTE
Am DATA Am DATA 1 P
NO ACK IN LAST
BYTE
During read cycle, the master generates start condition and then place the 1^st byte data that are combined
slave address (7 bits) with a read/write control bit to SDA line. After issue acknowledgment, 8 bits DATA was
also placed on SDA line by PAS109B. The 8 bit data was read from PAS109B internal control register that
address was assigned by previous write cycle. Follow the master acknowledgment, the PAS109B place the next 8
bits data (address is increment automatically) on SDA line and then transmit to master serially. The DATA and
Am cycles is repeat until the last byte read. After last byte read, Am is no longer generated by master but instead
by keep SDA line high. The slave (PAS109B) must releases SDA line to master to generate STOP condition.
(Please refer to Fig 5.3.)
SDA
SCL
S
Start
Condition
1-7
8
9
1-7
8
9
1-7
8
Address
R/W
ACK
from
Receiver
Data
ACK
Data
from
Receiver
Fig 5.3 Data Transfer Format
9
P
ACK Stop
from Condition
Receiver
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PixArt Imaging Inc.
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V1.1, Mar. 2002