Datasheet MAX30208 (Maxim) - 9

link to page 9 MAX30208 ±0.1°C Accurate, I2C Digital Temperature Sensor
Alarm Signaling
status bit, TEMP_LO or TEMP_HI is set in the STATUS After the device performs a temperature conversion, the [0x00] regsiter. When the alarm condition is detected and temperature value is compared with the user-defined the corresponding interrupt enable bit, TEMP_LO_EN or two’s complement alarm trigger values stored in the 2-byte TEMP_HI_EN is set in the INTERRUPT_ENABLE [0x01] Alarm High and 2-byte Alarm Low registers (see Figure 2). register and if GPIO0_MODE in the GPIO_SETUP [0x20] The default value for AH is 0x7FFF (+163.835°C) and the register is set to 0x3 then a hardware interrupt asserts default value for AL is 0x8000 (-163.840°C). The MSB on the GPIO0 pin. The status bits, the alarm flag and the indicates if the value is positive or negative; for positive hardware interrupt stay asserted until the STATUS [0x00] numbers the MSB is 0 and for negative numbers the register is read using the serial interface. The alarm flag MSB is 1. The alarm high threshold, AH is programmed only clears when STATUS is read. If the alarm flag is set in registers ALARM_HI_MSB [0x10] and ALARM_HI_ and the next result does not trip the flag, then the flag LSB [0x11]. The alarm low threshold, AL is programmed in remains set. registers ALARM_LO_MSB [0x12] and ALARM_LO_LSB If the alarm settings change while the device is under an [0x13]. alarm condition, the alarm status must be cleared and If the measured temperature is lower than AL or higher another temperature conversion executed to update the than AH, an alarm condition exists and corresponding alarm condition. ALARM HIGH THRESHOLD REGISTER FORMAT Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit9 Bit8 MSB AH15 AH14 AH13 AH12 AH11 AH10 AH9 AH8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 LSB AH7 AH6 AH5 AH4 AH3 AH2 AH1 AH0 ALARM LOW THRESHOLD REGISTER FORMAT Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit9 Bit8 MSB AL15 AL14 AL13 AL12 AL11 AL10 AL9 AL8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 LSB AL7 AL6 AL5 AL4 AL3 AL2 AL1 AL0 Figure 2. Alarm Threshold Register Format www.maximintegrated.com Maxim Integrated │ 9