adc.c File Reference

Read battery voltage. More...

#include <adc.h>
#include "em_adc.h"
#include "em_cmu.h"
#include "debug_dbprint.h"

Include dependency graph for adc.c:

Go to the source code of this file.

Functions
void	initADC (void)
	Initialisation of the ADC. More...
void	ADC0_IRQHandler (void)
	Interrupt handler for ADC. More...
void	ADC_Batt_Read (void)
	Do single ADC conversion (read) More...
void	ADC_Batt_print (void)
	Print battery in millivolts using dbprint. More...
void	ADC_get_batt (uint8_t *percent)
	Get battery in percentage. More...

Detailed Description

Read battery voltage.

Version

1.0

Author

Jona Cappelle

Definition in file adc.c.

Function Documentation

ADC0_IRQHandler()

void ADC0_IRQHandler

(

void

)

Interrupt handler for ADC.

Conversion from ADC read (0-4096) to millivolts

Definition at line 73 of file adc.c.

{
  // Clear the interrupt flag
  ADC_IntClear(ADC0, ADC_IFC_SINGLE);
 
  // Get ADC result
  sample = ADC_DataSingleGet(ADC0);
 
  // Calculate input voltage in mV, input voltage reference: 3.3V (3300)
  /* 2 V --|500k|--|1Meg|--- GND */
  millivolts = ( sample * 2000 * 15 ) / (4096 * 5 );
 
  // Start next ADC conversion
  /* This is for continuous measurements, not needed */
  /* When we want to read the ADC, we just call ADC_Start(ADC0, adcStartSingle) */
  //ADC_Start(ADC0, adcStartSingle);
}

References millivolts, and sample.

ADC_Batt_print()

void ADC_Batt_print

(

void

)

Print battery in millivolts using dbprint.

Definition at line 113 of file adc.c.

{
#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
    dbprint("Batt:  ");
    dbprintInt(millivolts);
#endif /* DEBUG_DBPRINT */
}

References dbprint(), dbprintInt(), and millivolts.

ADC_Batt_Read()

void ADC_Batt_Read

(

void

)

Do single ADC conversion (read)

Note

Takes minimal 1 µs

Definition at line 100 of file adc.c.

{
  // Start first conversion
  ADC_Start(ADC0, adcStartSingle);
 
}

Referenced by ADC_get_batt().

ADC_get_batt()

void ADC_get_batt

(

uint8_t *

percent

)

Get battery in percentage.

20 - 40 - 60 - 80 - 100 percent

Parameters

[out]

percent

Percentage of the remaining battery capacity

Definition at line 132 of file adc.c.

{
    ADC_Batt_Read();
 
    if(millivolts <= 3670) percent[0] = 20;
    else if(millivolts <= 3720) percent[0] = 40;
    else if(millivolts <= 3800) percent[0] = 60;
    else if(millivolts <= 3950) percent[0] = 80;
    else percent[0] = 100;
 
}

References ADC_Batt_Read(), and millivolts.

Referenced by CheckIMUidle().

initADC()

void initADC

(

void

)

Initialisation of the ADC.

Reference: VDD (=2V) Resolution 12bits Channel 4

Definition at line 32 of file adc.c.

{
  // Enable ADC0 clock
  CMU_ClockEnable(cmuClock_ADC0, true);
 
  // Declare init structs
  ADC_Init_TypeDef init = ADC_INIT_DEFAULT;
  ADC_InitSingle_TypeDef initSingle = ADC_INITSINGLE_DEFAULT;
 
  // Modify init structs and initialize
  init.prescale = ADC_PrescaleCalc(ADC_FREQ, 0); // Init to max ADC clock for Series 0
  init.timebase = ADC_TimebaseCalc(0);
 
  initSingle.diff       = false;        // single ended
  //initSingle.reference  = adcRef2V5;    // internal 2.5V reference
  initSingle.reference  = adcRefVDD;    // vdd reference voltage
  initSingle.resolution = adcRes12Bit;  // 12-bit resolution
 
  // Select ADC input. See README for corresponding EXP header pin.
  initSingle.input = adcSingleInputCh4;
 
  ADC_Init(ADC0, &init);
  ADC_InitSingle(ADC0, &initSingle);
 
  // Enable ADC Single Conversion Complete interrupt
  ADC_IntEnable(ADC0, ADC_IEN_SINGLE);
 
  // Enable ADC interrupts
  NVIC_ClearPendingIRQ(ADC0_IRQn);
  NVIC_EnableIRQ(ADC0_IRQn);
}