AN2799

Firmware description

11/14

4.1.4

Deletion

The power meter object is deleted by the DeletePowerMeterObj function implemented

externally by the object itself. This function first calls the deletion method to free dynamically

allocated variables during object creation (in this case does nothing) then frees the allocated

memory for the power meter object.

4.2

Hardware abstraction layer

The HAL is implemented using the following files:

●

PowerMeterHal.c

●

PowerMeterHal.h

●

PowerMeterHalTypes.h

This module is useful to abstract the power meter object implementation from the STM32

standard library.

4.2.1

HAL functions

The hardware abstraction layer functions are described as follows:

●

PM_ConfigSignal: this function configures a pin according to the passed signal

descriptor and configuration type.

●

PM_ReceiveRegOnSpi: this function receives the STPM01 internal register from the

SPI interface.

●

PM_OnSpiRxIrq: This function implements the interrupt service routine of the SPI

interface. It is called when the FIFO of the SPI peripherals contains 1 byte or more and

assigns the received value to a shared register variable.

●

SendClkToGetData: this function is used to provide the SPI clock to the STPM01 to

receive data.

●

ConfigPin: pin configuration function.

4.3

Application interface

The application interface is implemented using the following files:

●

Meter.c

●

MeterHal.c

●

MeterLayer.h

This layer is useful to abstract the application from the specific board used. In fact, the

functions implemented in the described modules allow the hardware configuration of the

specific board used. The firmware described in this document has been validated using the

“SmartPlug” board that includes two STPM01 meters enumerated as

PM_METER_TYPE_CONSUMPTION and PM_METER_TYPE_DISPERSION.