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287 lines
8.1 KiB
C
287 lines
8.1 KiB
C
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/*! \file pulse.c \brief Pulse/frequency generation function library. */
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//*****************************************************************************
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//
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// File Name : 'pulse.c'
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// Title : Pulse/frequency generation function library
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// Author : Pascal Stang - Copyright (C) 2000-2002
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// Created : 2002-08-19
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// Revised : 2003-05-29
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// Version : 0.7
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// Target MCU : Atmel AVR Series
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// Editor Tabs : 4
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//
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// This code is distributed under the GNU Public License
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// which can be found at http://www.gnu.org/licenses/gpl.txt
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//
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//*****************************************************************************
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#ifndef WIN32
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#include <avr/io.h>
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#include <avr/signal.h>
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#include <avr/interrupt.h>
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#include <avr/pgmspace.h>
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#endif
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#include "global.h"
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#include "timer.h"
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#include "pulse.h"
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// Global variables
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// pulse generation registers
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volatile static unsigned char PulseT1AMode;
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volatile static unsigned short PulseT1ACount;
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volatile static unsigned short PulseT1APeriodTics;
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volatile static unsigned char PulseT1BMode;
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volatile static unsigned short PulseT1BCount;
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volatile static unsigned short PulseT1BPeriodTics;
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// pulse mode bit definitions
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// PULSE_MODE_COUNTED
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// if true, the requested number of pulses are output, then output is turned off
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// if false, pulses are output continuously
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#define PULSE_MODE_CONTINUOUS 0x00
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#define PULSE_MODE_COUNTED 0x01
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// functions
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void pulseInit(void)
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{
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// initialize timer1 for pulse operation
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pulseT1Init();
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}
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void pulseT1Init(void)
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{
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// try to make sure that timer1 is in "normal" mode
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// most importantly, turn off PWM mode
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timer1PWMOff();
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// set some reasonable initial values
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// in case the user forgets to
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PulseT1AMode = 0;
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PulseT1BMode = 0;
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PulseT1ACount = 0;
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PulseT1BCount = 0;
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PulseT1APeriodTics = 0x8000;
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PulseT1BPeriodTics = 0x8000;
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// attach the pulse service routines to
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// the timer 1 output compare A and B interrupts
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timerAttach(TIMER1OUTCOMPAREA_INT,pulseT1AService);
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timerAttach(TIMER1OUTCOMPAREB_INT,pulseT1BService);
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}
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void pulseT1Off(void)
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{
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// turns pulse outputs off immediately
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// set pulse counters to zero (finished)
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PulseT1ACount = 0;
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PulseT1BCount = 0;
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// disconnect OutputCompare action from OC1A pin
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cbi(TCCR1A,COM1A1);
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cbi(TCCR1A,COM1A0);
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// disconnect OutputCompare action from OC1B pin
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cbi(TCCR1A,COM1B1);
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cbi(TCCR1A,COM1B0);
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// detach the pulse service routines
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timerDetach(TIMER1OUTCOMPAREA_INT);
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timerDetach(TIMER1OUTCOMPAREB_INT);
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}
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void pulseT1ASetFreq(u16 freqHz)
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{
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// set the frequency of the pulse output
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// we need to find the requested period/2 (in timer tics)
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// from the frequency (in hertz)
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// calculate how many tics in period/2
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// this is the (timer tic rate)/(2*requested freq)
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PulseT1APeriodTics = ((u32)F_CPU/((u32)timer1GetPrescaler()*2*freqHz));
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}
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void pulseT1BSetFreq(u16 freqHz)
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{
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// set the frequency of the pulse output
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// we need to find the requested period/2 (in timer tics)
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// from the frequency (in hertz)
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// calculate how many tics in period/2
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// this is the (timer tic rate)/(2*requested freq)
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PulseT1BPeriodTics = ((u32)F_CPU/((u32)timer1GetPrescaler()*2*freqHz));
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}
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void pulseT1ARun(u16 nPulses)
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{
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// set the number of pulses we want and the mode
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if(nPulses)
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{
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// if the nPulses is non-zero, use "counted" mode
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PulseT1AMode |= PULSE_MODE_COUNTED;
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PulseT1ACount = nPulses<<1;
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}
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else
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{
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// if nPulses is zero, run forever
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PulseT1AMode &= ~PULSE_MODE_COUNTED;
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PulseT1ACount = 1<<1;
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}
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// set OutputCompare action to toggle OC1A pin
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cbi(TCCR1A,COM1A1);
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sbi(TCCR1A,COM1A0);
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// now the "enabling" stuff
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// set the output compare one pulse cycle ahead of current timer position
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// to make sure we don't have to wait until the timer overflows and comes
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// back to the current value
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// set future output compare time to TCNT1 + PulseT1APeriodTics
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//outw(OCR1A, inw(TCNT1) + PulseT1APeriodTics);
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OCR1A += PulseT1APeriodTics;
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// enable OutputCompare interrupt
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sbi(TIMSK, OCIE1A);
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}
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void pulseT1BRun(u16 nPulses)
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{
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// set the number of pulses we want and the mode
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if(nPulses)
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{
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// if the nPulses is non-zero, use "counted" mode
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PulseT1BMode |= PULSE_MODE_COUNTED;
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PulseT1BCount = nPulses<<1;
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}
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else
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{
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// if nPulses is zero, run forever
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PulseT1BMode &= ~PULSE_MODE_COUNTED;
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PulseT1BCount = 1<<1;
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}
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// set OutputCompare action to toggle OC1B pin
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// (note: with all the A's and B's flying around, TCCR1A is not a bug)
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cbi(TCCR1A,COM1B1);
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sbi(TCCR1A,COM1B0);
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// now the "enabling" stuff
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// set the output compare one pulse cycle ahead of current timer position
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// to make sure we don't have to wait until the timer overflows and comes
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// back to the current value
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// set future output compare time to TCNT1 + PulseT1APeriodTics
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//outw(OCR1B, inw(TCNT1) + PulseT1BPeriodTics);
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OCR1B += PulseT1BPeriodTics;
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// enable OutputCompare interrupt
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sbi(TIMSK, OCIE1B);
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}
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void pulseT1AStop(void)
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{
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// stop output regardless of remaining pulses or mode
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// go to "counted" mode
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PulseT1AMode |= PULSE_MODE_COUNTED;
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// set pulses to zero
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PulseT1ACount = 0;
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}
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void pulseT1BStop(void)
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{
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// stop output regardless of remaining pulses or mode
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// go to "counted" mode
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PulseT1BMode |= PULSE_MODE_COUNTED;
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// set pulses to zero
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PulseT1BCount = 0;
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}
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u16 pulseT1ARemaining(void)
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{
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// return the number of pulses remaining for channel A
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// add 1 to make sure we round up, >>1 equivalent to /2
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return (PulseT1ACount+1)>>1;
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}
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u16 pulseT1BRemaining(void)
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{
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// return the number of pulses remaining for channel A
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// add 1 to make sure we round up, >>1 equivalent to /2
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return (PulseT1BCount+1)>>1;
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}
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void pulseT1AService(void)
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{
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// check if TimerPulseACount is non-zero
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// (i.e. pulses are still requested)
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if(PulseT1ACount)
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{
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//u16 OCValue;
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// read in current value of output compare register OCR1A
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//OCValue = inp(OCR1AL); // read low byte of OCR1A
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//OCValue += inp(OCR1AH)<<8; // read high byte of OCR1A
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// increment OCR1A value by PulseT1APeriodTics
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//OCValue += PulseT1APeriodTics;
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// set future output compare time to this new value
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//outp((OCValue>>8), OCR1AH); // write high byte
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//outp((OCValue & 0x00FF),OCR1AL); // write low byte
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// the following line should be identical in operation
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// to the lines above, but for the moment, I'm not convinced
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// this method is bug-free. At least it's simpler!
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//outw(OCR1A, inw(OCR1A) + PulseT1APeriodTics);
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// change again
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OCR1A += PulseT1APeriodTics;
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// decrement the number of pulses executed
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if(PulseT1AMode & PULSE_MODE_COUNTED)
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PulseT1ACount--;
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}
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else
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{
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// pulse count has reached zero
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// disable the output compare's action on OC1A pin
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cbi(TCCR1A,COM1A1);
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cbi(TCCR1A,COM1A0);
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// and disable the output compare's interrupt to stop pulsing
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cbi(TIMSK, OCIE1A);
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}
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}
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void pulseT1BService(void)
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{
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// check if TimerPulseACount is non-zero
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// (i.e. pulses are still requested)
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if(PulseT1BCount)
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{
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//u16 OCValue;
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// read in current value of output compare register OCR1B
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//OCValue = inp(OCR1BL); // read low byte of OCR1B
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//OCValue += inp(OCR1BH)<<8; // read high byte of OCR1B
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// increment OCR1B value by PulseT1BPeriodTics
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//OCValue += PulseT1BPeriodTics;
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// set future output compare time to this new value
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//outp((OCValue>>8), OCR1BH); // write high byte
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//outp((OCValue & 0x00FF),OCR1BL); // write low byte
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// the following line should be identical in operation
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// to the lines above, but for the moment, I'm not convinced
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// this method is bug-free. At least it's simpler!
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//outw(OCR1B, inw(OCR1B) + PulseT1BPeriodTics);
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// change again
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OCR1B += PulseT1BPeriodTics;
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// decrement the number of pulses executed
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if(PulseT1BMode & PULSE_MODE_COUNTED)
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PulseT1BCount--;
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}
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else
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{
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// pulse count has reached zero
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// disable the output compare's action on OC1B pin
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cbi(TCCR1A,COM1B1);
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cbi(TCCR1A,COM1B0);
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// and disable the output compare's interrupt to stop pulsing
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cbi(TIMSK, OCIE1B);
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}
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}
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