pulse.h

Go to the documentation of this file.

/*! \file pulse.h \brief Pulse/frequency generation function library. */
//*****************************************************************************
//
// File Name    : 'pulse.h'
// Title        : Pulse/frequency generation function library
// Author       : Pascal Stang - Copyright (C) 2000-2002
// Created      : 2002-08-19
// Revised      : 2003-05-29
// Version      : 0.7
// Target MCU   : Atmel AVR Series
// Editor Tabs  : 4
//
/// \ingroup driver_avr
/// \defgroup pulse Pulse/Frequency Generation Function Library (pulse.c)
/// \code
///     #include "timer.h"
///     #include "pulse.h"
/// \endcode
/// \par Overview
///     This library is designed to facilitate the output of square wave pulses
/// at a frequency determined by the user.  The user may specify a continuous
/// stream of pulses, or a certain fixed number. Common uses include stepper
/// motor speed control, tone generation, communications, etc.  The library
/// uses the AVR processor built-in timers and pulse output is on the timer
/// Output Compare (OC) pins.  This library requires the timer function
/// library to work.
///
/// The allowable range of frequencies which can be generated is governed
/// by the tic rate of the timer (therefore the CPU clock rate and the
/// timer prescaler), and the computing speed of the processor itself. See
/// the SetFreq commands for more details.
///
/// \Note In order for the pulse library to work, pulseInit() will attach
/// the pulse service routines to the timer interrupts using the
/// timerAttach function. You must not detach the service routines during
/// pulse library operation.
//
// This code is distributed under the GNU Public License
//      which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#ifndef PULSE_H
#define PULSE_H

#include "global.h"

// constants/macros/typdefs

// functions

// Master Pulse Commands
// pulseInit()
//      Initializes the pulse system/library.
void pulseInit(void);

// Pulse commands for timer1
// pulseT1Init()
//      configures the timer1 hardware to produce pulses on pins OC1A and OC1B.
//      A "pulse" is considered to be one high and low period of a square wave.
void pulseT1Init(void);

// pulseT1Off()
//      Turns pulse output off immediately (cancels running pulse operations).
//      Unconfigures hardware and interrupts.
void pulseT1Off(void);

//  pulseT1ASetFreq() and pulseT1BSetFreq()
//      sets the frequency in hertz for each channel of square-wave pulse output
//      Note1: the freqency <freqHz> must always be greater than zero
//      Note2: both channels share the same frequency range which is governed
//      by the timer1 prescaler setting.  A prescaler setting of DIV/8 allows
//      frequencies of a few hertz through a few kilohertz.
//
//      Lower frequency bound = overflow rate of timer1 at current prescaling
//      Upper frequency bound = the tics rate of timer1 at current prescaling,
//                              or approx. the (clock rate of the processor)/50,
//                              whichever is smaller
void pulseT1ASetFreq(u16 freqHz);
void pulseT1BSetFreq(u16 freqHz);

// pulseT1ARun() and pulseT1BRun();
//      Sets the number of square-wave pulses to be output on the given channel.
//      For continuous (unlimited) pulse output, use nPulses = 0.  Pulses begin
//      coming out immediately.
//      Note: <nPulses> must be between 0 and 32767
void pulseT1ARun(u16 nPulses);
void pulseT1BRun(u16 nPulses);

// pulseT1AStop() and pulseT1BStop();
//      Stop pulse output at the next cycle (regardless of the number of
//      remaining pulses).
void pulseT1AStop(void);
void pulseT1BStop(void);

// pulseT1ARemaining() and pulseT1BRemaining()
//      Returns the number of pulses remaining to be output for each channel.
//      This function is useful for figuring out if the pulses are done.
u16  pulseT1ARemaining(void);
u16  pulseT1BRemaining(void);

// pulseT1AService() and pulseT1BService()
//      Interrupt service routines for pulse output (do not call these functions directly)
void pulseT1AService(void);
void pulseT1BService(void);


#endif

---