
IMX135-0APH5-C
Read/Write operation of 2-wire serial communication
IMX135-0APH5-C has an index function that indicates which address to be accessed. When reading/writing the
value from/to an asked address, the Master must set the address value to the index. Index value is designated by
2-byte of dummy write operation after the slave address transmission. The index value is automatically
incremented “one” by the “Acknowledge/Negative Acknowledge” for data transfer.
IMX135-0APH5-C supports for of read modes and two of write modes being compliant to SMIA 1.0 Part2
Specification; Cemera Control Interface (CCI).
Table 6 Operations Supported by 2-wire Serial Communication
CCI Single read from random location
(Single read from an arbitrary address)
CCI Single read from current location
(Single read from the held address)
CCI sequential read starting from random location
(Sequential read starting from an arbitrary address)
CCI sequential read starting from current location
(Sequential read starting from the held address)
CCI single write to random location
(Single write to an arbitrary address)
CCI sequential write starting from random location
(Sequential write starting from an arbitrary address)
CCI single read from random location
The upper level of the figure below shows the sensor internal index value, and the lower level shows the SDA I/O
data flow. The master sets the sensor index value to M by designating the sensor slave address with a write
request,and then designating the address (M). After that the Master generates the Start condition. The Start
condition is generated without generating the Stop condition, so it becomes the Repeated Start condition. Next,
when the Master sends the slave address with a read request, the sensor outputs an Acknowledge followed
immediately by the index address data on SDA. After the Master receives the data, it generates a Negative
Acknowledge and the Stop condition to end the communication.
When reading single datum from asked address register, the master device starts write-operation with the slave
address of IMX135-0APH5-C and by making 2-bytes of dummy write master sets the address value (M) to the
index. After that master issue the “start condition” again instead of issuing “stop condition”. This “start condition” is
recognized as “repeated start condition”. Then transmitting the read request with the slave address,
IMX135-0APH5-C issues the “Acknowledge” and start transmitting the register value from indexed address (M).
Master issues the “Negative Acknowledge” and “stop condition” after receiving the transmission.
The figure below indicates the transition of index value and data on SDA line.
From Master to Slave
From Slave to Master
0 AS A A A P1 A
Sr
Previous Index value Index M
S = Start Condition
Sr = Repeated Start Condition
P = Stop Condition
A = Acknowledge
A = Negative Acknowledge
Index
M + 1
Slave Address
[7:1]
Register Address
[15:8]
Register Address
[7:0]
Slave Address
[7:1]
Data
[7:0]
Index, value M
Figure 12 CCI single read from random location
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