Connect Sensor with ATMEGA16 Code

ADC (Analog to Digital Converter) module is available with a number of AVR MCUs. Several library routines are included to provide you comfortable work with the module in single-ended mode.

Library Routines

• ADC_Init
• ADCx_Init_Advanced
• ADC_Get_Sample
• ADC_Read

ADC_Init

Prototype	void ADC_Init(); // for XMEGA family of MCUs void ADCx_Init();
Returns	Nothing.
Description	Initializes internal ADC module to work with XTAL frequency prescaled by 128. Clock determines the time period necessary for performing A/D conversion. For XMEGA family of MCUs change the X in the routine prototype with A or B.
Requires	MCU with built-in ADC module.
Example	ADC_Init(); // Initialize ADC module with default settings ADCA_Init(); // Initialize ADC module with default settings

ADCx_Init_Advanced

Prototype	void ADCx_Init_Advanced(unsigned AdcMode, unsigned Reference);
Returns	Nothing.
Description	Initializes internal ADC module to work with user defined settings. Exist only for XMEGA family of MCUs In order to use this routine, change the X in the routine prototype with A or B. Parameters AdcMode and Reference determine the work mode for ADC module and can have the following values: Description Predefined library const Resolution of ADC module : 8 bit resolution _ADC_8bit 12 bit resolution _ADC_12bit Voltage Reference : Internal 1V _ADC_INTERNAL_REF_1V Internal VCC/1.6V _ADC_INTERNAL_REF_VCC External Reference on PORTA _ADC_EXTERNAL_REF_A External Reference on PORTB _ADC_EXTERNAL_REF_B
Requires	MCU with built-in ADC module.
Example	ADCA_Init_Advanced(_ADC_12bit, _ADC_INTERNAL_REF_1V); // Initialize ADC module with 12bit resolution and internal voltage reference of 1V

ADC_Get_Sample

Prototype	unsigned ADC_Get_Sample(unsigned short channel); // for XMEGA family of MCUs unsigned ADCx_Get_Sample(unsigned short channel);
Returns	10-bit or 12-bit unsigned value (MCU dependent) from the specified channel.
Description	Routine acquires analog value from the specified channel. Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping. For XMEGA family of MCUs change the X in the routine prototype with A or B.
Requires	The MCU with built-in ADC module. Prior to using this routine, ADC module needs to be initialized.
Example	unsigned adc_value; ... ADC_Init(); // Initialize ADC module with default settings adc_value = ADC_Get_Sample(2); // Acquire analog value from channel 2

ADC_Read

Prototype	unsigned ADC_Read(char channel); // for XMEGA family of MCUs unsigned ADCx_Read(char channel);
Returns	10-bit or 12-bit unsigned value (MCU dependent) from the specified channel.
Description	Routine initializes internal ADC module and acquires analog value from the specified channel. Clock determines the time period necessary for performing A/D conversion. Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping. For XMEGA family of MCUs change the X in the routine prototype with A or B.
Requires	Nothing.
Example	unsigned adc_value; ... adc_value = ADC_Read(2); // initialize ADC module and acquire analog value from ADC module channel 2

Library Example

This example code reads analog value from channel 2 and displays it on PORTB and PORTC.

Code For ADC

#include <built_in.h>
unsigned int adc_rd;

void main() {

  DDRB = 0xFF;               // Set PORTB as output
  DDRC = 0xFF;               // Set PORTC as output
  
  while (1) {
    adc_rd = ADC_Read(2);    // get ADC value from 2nd channel
    PORTB = adc_rd;          // display adc_rd[7..0]
    PORTC = Hi(adc_rd);      // display adc_rd[9..8]
  }
}

HW Connection