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AT42QT1060 [DATASHEET]
9505H–AT42–04/2015
4.3 Data Read/Write
4.3.1 Writing Data to the Device
The sequence of events required to write data to the device is shown next
.
1. The host initiates the transfer by sending the START condition
2. The host follows this by sending the slave address of the device together with the WRITE bit.
3. The device sends an ACK.
4. The host then sends the memory address within the device it wishes to write to.
5. The device sends an ACK.
6. The host transmits one or more data bytes; each is acknowledged by the device.
7. If the host sends more than one data byte, they are written to consecutive memory addresses.
8. The device automatically increments the target memory address after writing each data byte.
9. After writing the last data byte, the host should send the STOP condition.
Note: the host should not try to write beyond address 255 because this is the limit of the device’s internal memory
address.
4.3.2 Reading Data From the Device
The sequence of events required to read data from the device is shown next.
1. The host initiates the transfer by sending the START condition
2. The host follows this by sending the slave address of the device together with the WRITE bit.
3. The device sends an ACK.
4. The host then sends the memory address within the device it wishes to read from.
5. The device sends an ACK.
Table 4-1. Description of Write Data Bits
Key Description
S Start condition
SLA+W Slave address plus write bit
A Acknowledge bit
MemAddress Target memory address within device
Data Data to be written
P Stop condition
SLA+W
MemAddress
AAS
Data A
P
Host to Device Device Tx to Host
SLA+W
MemAddress
AAS
S
SLA+R A
A
P
Host to Device Device Tx to Host
P
A
A
Data 1
Data 2
Data n
