Example : ADC

ADC components of OSS-EC

The ADC component of the OSS-EC is used as an example here. BSL00000057 is described as an example program.

• Block diagram of ADC components architecture and OSS-EC architecture ( fig 1. )
• ADC component state flow ( fig 2. )
• API ( fig 3. )

Blue label characters are data related to User-defined.
Green label characters are data related to model number.

BSL00000057 Features

– Component type	ADC component
– Number of Components	Single
– Supported OS (HAL)	Arduino
– Calculation	Floating-point
– Conversion type	Linear
– Moving average filter	Moving average filter select ( Non,SMA,EMA,WMA )
– Diagnosis	Range (Min to Max)

Example download

An example using NXP’s MPXA4250A can be downloaded below.

ｙ	physical value
ai	A/D conversion value
vi	Sensor output voltage value
Vdd	Sensor supply voltage(ADC_vdd) value
ADC_bit	A/D conversion bit length
PP	Program of OSS-EC
MP	Microcontroller 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 / ( 2^ADC_bit )

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

y = f(vi) = ( vi – x_offset ) / gain + y_offset range min to max

x_offset	Sensor output voltage offset value [V]
gain	Voltage value to physical value conversion gain
y_offset	Physical offset value
min	Physical value min
max	Physical value max

Software Option

Moving average select

#define	iMA	iSMA	Simple moving average filter phy = ( yn + yn-1 + yn-2 … ) / n n : iABCDEF_SMA_num
#define	iMA	iEMA	Exponential moving average filter phy = ( y × k ) + ( phyn-1 × ( 1 – k ) ) k :  iABCDEF_EMA_K
#define	iMA	iWMA	Weighted moving average filter phy = ( ( yn × 1 ) + ( yn-1 × 2 ) + ( yn-2 × 3 ) … ) / ( 1 + 2 + 3 … ) n : iABCDEF_WMA_num
#define	iMA	iNonMA	Non-moving average  filter

typedef struct
{
	uint32	sts;	// Diagnosis result of range min to max
	float32	phy;	// Sensor physical value
}pp2ap_adc_t;

sts Normal = iNormal, Over Max = iMax_NG, Under Min = iMin_NG