SBOS891B October 2018 – April 2021 TMP144
At device power-up, every TMP144 in the daisy-chain is connected in transparent mode, as shown in Figure 7-7.
As shown in Figure 7-8, the host must send the initialization command (C[7:0] = 10001100) for the bus to program its internal address, depending on the number of devices on the bus.
The host must then send the address assignment command, consisting of C[7:4] = 1001 and C[3:0] = 0000, where C[3:0] represents the address of the first device in the chain. This word is stored internally as its device ID. The first device increments the unit in the device address and then reconnects the bus, as shown in Figure 7-10. This address is then sent to the next device in the chain.
After all devices on the chain have received the respective addresses, the host receives the last programmed address on the chain + 1. The host can use this information to determine the total number of devices in the chain and the respective address of each device.
After the initialization sequence, every device can be addressed individually or through global commands. This global initialization sequence is a requirement and must be performed before any other communication.