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// Function to initialise PWM of AVR
//
// Calling Sequence
// u8AVRPWMSetups(uint8 timer, uint8 prescalar, uint8 waveform_mode, uint8 output_mode)
//
// Parameters
// timer: timer to be used for PWM generation (0,1,2)
// prescalar: prescalar to be used for generating PWM waveform (0-7)
// waveform_mode: decides type of waveform generation
// 0 -> Normal mode
// 1 -> Phase correct mode
// 2 -> CTC mode
// 3 -> Fase PWM mode
// output_mode: decides the compare output mode. (0-3)
// behaviour of the output is different for different inputs
// depending upon 'waveform_mode' chosen.
// ***Refer datasheet for more description about above modes
//
// Description
// This function initialises PWM of AVR with given parameters. 'timer'
// decides which of the three (0,1,2) timers available to be used. The
// 'prescalar' is needed for deciding PWM clock. Select appropriate prescalar
// depending on MCU clock. Choose required pwmmode using 'waveform_generation'
// and 'output_mode'. Please refer datasheet for more description of 'wafefom_mode'
// and 'output mode'.
// Examples
// AVRPWMSetup(0,1,2,2)
//
// Authors
// Siddhesh Wani
//
#include "AVRPeripheralPWM.h"
uint8 u8AVRPWMSetups(uint8 timer, uint8 prescalar, uint8 waveform_mode, uint8 output_mode)
{
switch(timer)
{
case 0:
TCCR0|= (prescalar & 0x07); //Select clock source
//Select waveform generation mode
TCCR0|= ((waveform_mode & 0x04) << 4);
//Select compare output mode
TCCR0 |= ((output_mode & 0x01) << 3); //WGM0
TCCR0 |= ((output_mode & 0x02) << 6); //WGM1
break;
case 1:
break;
case 2:
TCCR2|= (prescalar & 0x07); //Select clock source
//Select waveform generation mode
TCCR2|= ((waveform_mode & 0x04) << 4);
//Select compare output mode
TCCR2 |= ((output_mode & 0x01) << 3); //WGM0
TCCR2 |= ((output_mode & 0x02) << 6); //WGM1
break;
}
return 0;
}
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