TIDUEO0C July 2019 – March 2021
For the lowest possible power consumption, the ADS7142 nanopower sensor monitor is programmed to run from the low-power oscillator with nCLK = 18, which is the minimum recommended value setting in the nCLK_SEL register. According to the ADS7142 Nanopower, Dual-Channel, Programmable Sensor Monitor Data Sheet, this results in a conversion time in the range of 18 × 95.2 µs or 18 × 300 µs, or approximately 1.7 to 5.4 ms. Thus, the lowest sampling rate is not a fixed value, which must be considered when evaluating the load profile and the firmware timings for data read out in the application.
The Post Alert data mode is one of the Autonomous modes and is selected by the OPMODE_SEL register setting 0x110b. This directs the device to capture the next sixteen conversion results after the Alert has become active. Once these sixteen conversions are stored in the internal data buffer, all conversion stops and the host MCU can read out the values.