Datasheet

9596A–AT42–10/10

AT42QT1070

Figure A-5. Data Byte Format

A.6 Combining Address and Data Bytes into a Transmission

A transmission consists of a START condition, an SLA+R/W, one or more data bytes and a

STOP condition. The wired “ANDing” of the SCL line is used to implement handshaking between

the host and the device. The device extends the SCL low period by pulling the SCL line low

whenever it needs extra time for processing between the data transmissions.

Note: Each write or read cycle must end with a stop condition. When reading, a repeated

START is allowed. So S, SLA+W, A, S, SLA+R, A, DATA1, A,......,DATAx, /A, P can be sent.

Figure 6-1 shows a typical data transmission. Note that several data bytes can be transmitted

between the SLA+R/W and the STOP.

Figure 6-1. Byte Transmission

SCL from

Master

SLA+R/W

12 789

SDA from

Transmitter

Aggregate

SDA

Data MSB Data LSB ACK

Data Byte

SDA from

Receiver

STOP or

Next Data Byte

12 789

Data MSB Data LSB ACK

Data Byte STOP

SDA

SCL

Addr MSB Addr LSB R/W ACK

START SLA+R/W