Example : ADC

ADC components of OSS-EC

In this section, we will use the OSS-EC ADC component as an example.

  • Block diagram of ADC components and OSS-EC software ( fig.1 )
  • OSS-EC flowchart for ADC components ( fig.2)

Blue label characters are data related to components.
Red label characters are data related to the MPU.
Green label characters are data related to the circuit.

physical value
vi Sensor output signal
ai      Circuit output voltage
PCMPProgram component of OSS-EC
MPMicrocontroller unit program
ADC unit program
ai = f(ch)
CP      
Circuit/IC components program
Conversion formula from circuit output voltage to sensor output signal value
vi = f(ai)
SP      System components program
Conversion formula from sensor output signal value to physical value
y = f(vi)

The conversion formula for vi shall be as follows.

vi = f(ai) = ai * ADC_vdd / ( 2ADC_bit )× K_tc

ADC_Vdd Sensor supply voltage [V]
ADC_bit     
ADC conversion of MPU Bit number
CAUTION:When Mbed is selected, 16bit is fixed
K_tc      Circuit/IC transformer circuit constants

The conversion formula for y is as follows. ( Liner conversion )
Let it be a linear transformation equation.

y = f(vi) =( vi – x_offset ) / k_gain + y_offset

x_offset  Voltage Offset [V]
k_gain      Voltage/Physical Value Conversion Constant
y_offset     physical value Offset

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