Temperature measurement data is taken over a default range of 0°C to 127°C for both local and remote locations. Measurements from –55°C to 150°C can be made both locally and remotely by reconfiguring the TMP411-Q1 and TMP411D-Q1 devices for the extended temperature range. To change the TMP411-Q1 and TMP411D-Q1 configuration from the standard to the extended temperature range, switch bit 2 (RANGE) of the Configuration Register from low to high.

Temperature data resulting from conversions within the default measurement range are represented in binary form, as listed in the standard binary column of Table 7-1. Note that any temperature below 0°C results in a data value of zero (00h). Likewise, temperatures above 127°C result in a value of 127 (7Fh). The device can be set to measure over an extended temperature range by changing bit 2 of the Configuration Register from low to high. The change in measurement range and data format from standard binary to extended binary occurs at the next temperature conversion. For data captured in the extended temperature range configuration, an offset of 64 (40h) is added to the standard binary value, as listed in the extended binary column of Table 7-1. This configuration allows measurement of temperatures below 0°C. Note that binary values corresponding to temperatures as low as –64°C, and as high as 191°C are possible; however, most temperature-sensing diodes only measure within the range of –55°C to 150°C. Additionally, the TMP411-Q1 and TMP411D-Q1 devices are rated only for ambient local temperatures ranging from –40°C to 125°C. Parameters in the Absolute Maximum Ratings table must be observed.

The TMP411-Q1 and TMP411D-Q1 devices' temperature sensor does not utilize 2's complement format to read in temperature values. For this reason, the decode does not cast them into a signed type. The way the TMP411-Q1 and TMP411D-Q1 devices express a negative temperature is by enabling a RANGE bit, which adds 64°C to the result. When RANGE is enabled, the decode must subtract 64, causing a raw value of 0 to become –64°C output.

/* 12-bit format will have 4 bits discarded by right shift
 q4 is 0.062500 resolution
 the following bytes represent 24.5C
 there is no cast into signed type */
uint8_t byte1 = 0x18;
uint8_t byte2 = 0x80;
float f = ((byte1 << 8 | byte2) >> 4) * 0.0625f;
int mC = ((byte1 << 8 | byte2) >> 4) * 1000 >> 4;
int C = byte1;

Both local and remote temperature data use two bytes for data storage. The high byte stores the temperature with 1°C resolution. The second or low byte stores the decimal fraction value of the temperature and allows a higher measurement resolution; see Table 7-4. The measurement resolution for the remote channel is 0.0625°C and is not adjustable. The measurement resolution for the local channel is adjustable; the resolution can be set for 0.5°C, 0.25°C, 0.125°C, or 0.0625°C by setting the RES1 and RES0 bits of the Resolution Register; see Table 8-4.