The TMP451-Q1 device is two-wire and SMBus-compatible. Figure 7-4 and Figure 7-5 show the timing for various operations on the TMP451-Q1 device. The bus definitions are as follows:
Bus Idle:Both SDA and SCL lines remain high.
Start Data Transfer:A change in the state of the SDA line, from high to low, while the SCL line is high, defines a start condition. Each data transfer initiates with a start condition.
Stop Data Transfer:A change in the state of the SDA line from low to high while the SCL line is high defines a stop condition. Each data transfer terminates with a repeated start or stop condition.
Data Transfer:The number of data bytes transferred between a start and a stop condition is not limited and is determined by the master device. The receiver acknowledges data transfer.
Acknowledge:Each receiving device, when addressed, is obliged to generate an acknowledge bit. A device that acknowledges must pull down the SDA line during the acknowledge clock pulse in such a way that the SDA line is stable low during the high period of the acknowledge clock pulse. Take setup and hold times into account. On a master receive, data transfer termination can be signaled by the master generating a not-acknowledge on the last byte that has been transmitted by the slave.