Wiring language Analogue Pins in AURIX™

It's now time to port the Analogue functions as defined by Wiring language: analogRead()

Now, in reference to the board and pin mapping, it's good to recap:

Where: the analogRead() method reads the value of an analog input pin. Possible values range is 0-1023, where 0 is 0 volts and 1023 is 3.3 volts.

To implement such, I use the background scan: "the Versatile Analog-to-Digital Converter (VADC) is configured to measure multiple analog signals in a sequence using background scan request".

Such is done by:

1. configuring the respective analogue ports (AN0 .. AN5)
2. configuring the VADC to background scan (done by "wiring_analog_init(void)")
3. wrap the analogRead() function
   
   

configuring the respective analogue ports (AN0 .. AN5)

Such is realized by:

[..]
// Port Numeric Definition - Analogue Pins
#define A0 20
#define A1 21
#define A2 22
#define A3 23
#define A4 24
#define A5 25
#define TRIMM 26
//...

configuring the VADC to background scan

Such is realized by:

void wiring_analog_init(void)
{
initVADCModule(); /* Initialize the VADC module */
initVADCGroup(); /* Initialize the VADC group */
initVADCChannels(); /* Initialize the used channels */

/* Start the scan */
IfxVadc_Adc_startBackgroundScan(&g_vadc);
}

wrap the analogRead() function

Such is realized by:

uint16 analogRead(uint8 pin)
{
uint16 value = 0;
// Select the required channel in channel pending register
switch(pin)
{
// A0 P40.9 ADC0: AN39 / VADCG4.7
case A0:
value = readADCValue(CHN_39);
break;

// A1 P40.8 ADC1: AN38 / VADCG4.6
case A1:
value = readADCValue(CHN_38);
break;

// A2 P40.7 ADC2: AN37 / VADCG4.5
case A2:
value = readADCValue(CHN_37);
break;

// A3 P40.6 ADC3: AN36 / VADCG4.4
case A3:
value = readADCValue(CHN_36);
break;

[..]
}

// Return ADC Conversion
return (value);
}