52832 timer consumes a lot of power

[Август]

Hello 

A project that recently made a sensor found that the timer consumes a lot of power.

I built a timer to collect sensor data in the timer handler.

Sensor only cost 10uA, but I got 4ma  5ms .

I understand that there is no time-consuming operation in the timer handler, so do you have a good way to process the sensor data?

Thank you

[Turbo J]

Pretty much impossible to recommend anything since we have zero clue what task_read_kx022() actually does.

By the looks of your scope output it busy-waits for the I²C transaction (or transactions ?) to finish - you could change that to use the I²C event handler, but this obviously requires non-trivial changes to the source code.

Note: Does this sensor support SPI? That could transfer data one order of magnitude faster...

[Август]

Thank you.

I have used the I²C event handler but it also need to wait ack

Yes it support SPI. 

I tried to add a 5ms delay to the timer handler. The result is the same. It seems that the iic read and write operation is delayed by 5ms here.

task_read_kx022() is reading triaxial acceleration data with iic.

[Turbo J]

The line

while (m_transfer_done==0);

alone consumes the majority of your 4mA current consumtion over 5ms, because the MCU core will stay active the whole time doing pretty much nothing.

However, removing this line requires a code redesign that I would not consider trivial or beginner friendly, but the experience could teach you event-based programming (or properly using event handlers).

[Patrick]

Would you happen to have a resource that explains event based programming in the context of a device driver using a peripheral such as TWI or SPI? The Nordic examples of using TWI/SPI with an event handler does not really do more than add a wait loop that may sleep while waiting on an event.

[Август]

Thank you