Conclusion

AN2799

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4.3.1

Application interface functions

The application interface functions are described as follows:

●

PM_HwMetersCommonInit: this function configures the SPI peripheral (including the

interrupt controller), the STM32 MCO pin to provide the clock to both STPM01 and a

GPIO as input, useful to select two different operational modes:

–

Normal Mode: typical operational mode.

–

Calibration Mode: used to calibrate the STPM01 devices by an external tool. In

this mode the STM32 provides only the clock to the STPM01 devices.

These configurations are common to both STPM01 devices.

●

M_HwMeterSignalsInit: this function initializes the signals specific for an STPM01. In

detail, the STM32 GPIO is used as the SCS for the specific device. The specific

STPM01 device is selected by an enumerator as already stated.

●

ActivateMeter: this function includes all the operations to be done using the power

meter object for the STPM01 initialization.

All the initialization operations have been included in a single initialization procedure: Init,

establishing a power meter object and the STPM01 device identifier as parameters.

5

Conclusion

Summarizing, this document explains how to interface the STPM01 energy meter device to

the STM32x microcontroller including an easy-to-use firmware library. The firmware library

also includes the file ExampleApp.c which shows how to use the library itself. The user

application has to perform the standard STM32 configuration and simply call the

NewPowerObj for each STPM01 device to allocate the object, call the Init to perform the

power meters related initializations and configurations, call the ReadMeasure method to get

the data from STPM01 device and call GetVoltage and/or GetCurrent to get the last

measurement data.