Firmware description

AN2799

10/14

●

WriteConfigBit: this function writes a configuration bit of the STPM01 configuration

register formatting an 8-bit command word as the following:

The configuration word is sent to the STPM01 by the SPI interface.

●

WriteConfigRegs: this function writes the entire CFL and CFH configuration registers of

the STPM01.

●

ReadRegisters: this function reads the registers from the STPM01 and assigns the

read values to the power meter object registers attribute. The number of read registers

depends on the RegToReadNum passed parameter.

●

ReadMeasure: this function reads the RMS voltage and current registers from the

STPM01, calculates the real RMS values by multiplying the values of each register by

the calibration factors and assigns these values to the m_Voltage and m_Current

attributes of the power meter object.

●

GetVoltage: this function retrieves the last read voltage value in mV.

●

GetCurrent: this function retrieves the last read current value in mA.

●

GetEnergy: this function retrieves the last read energy value in mW.

●

OnSpiRxIrq: SPI interrupt event. Not used in this implementation. The SPI interrupt is

managed externally by the power meter object implementation.

4.1.3

Construction

The power meter object is constructed by the NewPowerMeterObj function implemented

externally by the object itself. This function allocates the memory for the object, assigns the

create method and calls it to assign the rest of the object properties.

1 bit data

6 bits configuration bits

1 bit don’t care

Figure 4.

Reset sequence

AM00079v1