Hi,
We are planning to use TMAG5170A2 to autowakeup when a magnetic threshold is reached and then wakeup a BLE controller.
But is it possible to then update the threshold to a higher value and go back to auto wakeup mode? If so what is the resolution of that threshold?
During auto wakeup function, does the sensor consume only 1.5uA in total, or during sleep it consumes 1.5uA and when it wakes up it consumes in mA?
Ranjith,
In wake and sleep mode, the device may be set to periodically wake into active mode and take a sample. After the conversion, if the thresholds are set the device will make a comparison, and then trigger on ALERT if the thresholds have been crossed. Then the device will return to sleep mode.
While running a conversion, the device enters the active mode for a duration that will depend on how many channels are active, what sampling pattern is selected, and the number of averages. The current for both active and sleep modes are shown here:
The average current consumption would be calculated by considering the total conversion time at the active mode current, followed by the sleep time at the sleep mode current.
The thresholds may be changed at any time, but initiating a SPI communication will bring the device back out of sleep mode and into configuration mode. After changing the thresholds, you would need to send a command to return to wake and sleep mode.
The threshold resolution is dependent on the input range setting. The calculation for each axis is the same, and is shown in the register map in the data sheet:
Thanks,
Scott
Hi Scott,
Thank you for your quick response. In the datasheet i saw the below table where average power is given when in duty cycle mode. I believe it is the same as wake and sleep mode. They have mentioned data active rate. Does data active rate of 1Hz mean that sensor wakes up and checks the threshold every second?
