JAJSGU6C October 2014 – April 2021 TMP451-Q1
PRODUCTION DATA
The TMP451-Q1 device has multiple 8-bit registers that hold temperature measurement results. The eight most significant bits (MSBs) of the local temperature sensor result are stored in register 00h, while the four least significant bits (LSBs) are stored in register 15h (the four MSBs of register 15h). The eight MSBs of the remote temperature sensor result are stored in register 01h, and the four LSBs are stored in register 10h (the four MSBs of register 10h). The four LSBs of both the local sensor and the remote sensor indicate the temperature value after the decimal point (for example, if the temperature result is 10.0625°C, the high byte is 0000 1010 and the low byte is 0001 0000). These registers are read-only and are updated by the ADC each time a temperature measurement is completed.
When the full temperature value is needed, reading the MSB value first causes the LSB value to be locked (the ADC does not write to it) until it is read. The same thing happens upon reading the LSB value first (the MSB value is locked until it is read). This mechanism assures that both bytes of the read operation are from the same ADC conversion. This assurance remains valid only until another register is read. For proper operation, read the high byte of the temperature result first. Read the low byte register in the next read command; if the LSBs are not needed, the register may be left unread. The power-on reset value of all temperature registers is 00h.