Configuration Register 2 (pointer address 1Ah for the TMP431 and 3Fh for the TMP432) controls which temperature measurement channels are enabled and whether the external channels have the resistance correction feature enabled or not.
The RC bit enables the resistance correction feature for the external temperature channels. If RC = 1, series resistance correction is enabled; if RC = 0, resistance correction is disabled. Resistance correction must be enabled for most applications. However, disabling the resistance correction can yield slightly improved temperature measurement noise performance, and reduce conversion time by about 50%, which could lower power consumption when conversion rates of two per second or less are selected.
The LEN bit enables the local temperature measurement channel. If LEN = 1, the local channel is enabled; if LEN = 0, the local channel is disabled.
The REN bit enables external temperature measurement channel 1 (connected to pins 2 and 3.) If REN = 1, the external channel is enabled; if REN = 0, the external channel is disabled.
For the TMP432 only, the REN2 bit enables the second external measurement channel (connected to pins 4 and 5). If REN2 = 1, the second external channel is enabled; if REN2 = 0, the second external channel is disabled.
The temperature measurement sequence is local channel, external channel 1, external channel 2, shutdown, and delay (to set conversion rate, if necessary). The sequence starts over with the local channel. If any of the channels are disabled, they are skipped in the sequence. Table 8 summarizes the bits of Configuration Register 2.
|CONFIGURATION REGISTER 2
(Read, Write = 1 A for TMP431 3F for TMP432; POR = 1Ch for TMP431; 3Ch for TMP432)
|BIT||NAME||FUNCTION||POWER-ON RESET VALUE|
|5||REN2||0 = External channel 2 disabled
1 = External channel 2 enabled
| 0 (TMP431)
|4||REN||0 = External channel 1 disabled
1 = External channel 1 enabled
|3||LEN||0 = Local channel disabled
1 = Local channel enabled
|2||RC||0 = Resistance correction disabled
1 = Resistance correction enabled