All along I've been measuring the currents of a breadboarded circuit. It was only prudent to check to see how the pcb versions are doing. Both units have been loaded with the latest firmware version. Here are the values I got for the two units.
|Standby mode||Current (µA)||Battery voltage (V)|
|1st unit (April 28)||2.05||0.48||0.74||3.099|
|2nd unit (May 6)||2.29||0.56||0.80||3.207|
The earlier unit didn't use a new battery. Its initial voltage was around 3.14 when I installed it in the circuit. The latest unit does use a new one. With a higher voltage than the 3.0V of the breadboarded version the higher currents are surprising. The latest unit, however, seems to be drawing a lot more current. But it seems to be within the specs of the MCU. Then again there could be some leakage current along the board.
I failed to mention in the last post that I also measured the DAC and voltage comparator currents in the breadboarded version. I modified the firmware so that the comparator was kept enabled throughout. I then measured the standby current. Thereafter, I changed the firmware back to its original form and kept the DAC enabled throughout and measured the standby current. I obtained a DAC current of approximately 19µA and a voltage comparator current of around 4.5µA. Enabling these modules only during probe reads does indeed help minimize power consumption.