timerx8.h

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/*! \file timerx8.h \brief Timer function library for ATmegaXX8 Processors. */
//*****************************************************************************
//
// File Name    : 'timerx8.h'
// Title        : Timer function library for ATmegaXX8 Processors
// Author       : Pascal Stang - Copyright (C) 2000-2005
// Created      : 11/22/2000
// Revised      : 06/15/2005
// Version      : 1.0
// Target MCU   : Atmel AVR Series
// Editor Tabs  : 4
//
// This code is distributed under the GNU Public License
//      which can be found at http://www.gnu.org/licenses/gpl.txt
//
/// \ingroup driver_avr
/// \defgroup timerx8 Timer Function Library for ATmegaXX8 (timerx8.c)
/// \code #include "timerx8.h" \endcode
/// \par Overview
///     This library provides functions for use with the timers internal
///     to the AVR processors.  Functions include initialization, set prescaler,
///     calibrated pause function (in milliseconds), attaching and detaching of
///     user functions to interrupts, overflow counters, PWM. Arbitrary
///     frequency generation has been moved to the Pulse Library.
///
/// \par About Timers
///     The Atmel AVR-series processors each contain at least one
///     hardware timer/counter.  Many of the processors contain 2 or 3
///     timers.  Generally speaking, a timer is a hardware counter inside
///     the processor which counts at a rate related to the main CPU clock
///     frequency.  Because the counter value increasing (counting up) at
///     a precise rate, we can use it as a timer to create or measure 
///     precise delays, schedule events, or generate signals of a certain
///     frequency or pulse-width.
/// \par
///     As an example, the ATmega163 processor has 3 timer/counters.
///     Timer0, Timer1, and Timer2 are 8, 16, and 8 bits wide respectively.
///     This means that they overflow, or roll over back to zero, at a
///     count value of 256 for 8bits or 65536 for 16bits.  A prescaler is
///     avaiable for each timer, and the prescaler allows you to pre-divide
///     the main CPU clock rate down to a slower speed before feeding it to
///     the counting input of a timer.  For example, if the CPU clock
///     frequency is 3.69MHz, and Timer0's prescaler is set to divide-by-8,
///     then Timer0 will "tic" at 3690000/8 = 461250Hz.  Because Timer0 is
///     an 8bit timer, it will count to 256 in just 256/461250Hz = 0.555ms.
///     In fact, when it hits 255, it will overflow and start again at
///     zero.  In this case, Timer0 will overflow 461250/256 = 1801.76
///     times per second.
/// \par
///     Timer0 can be used a number of ways simultaneously.  First, the
///     value of the timer can be read by accessing the CPU register \c TCNT0.
///     We could, for example, figure out how long it takes to execute a
///     C command by recording the value of \c TCNT0 before and after
///     execution, then subtract (after-before) = time elapsed.  Or we can
///     enable the overflow interrupt which goes off every time T0
///     overflows and count out longer delays (multiple overflows), or
///     execute a special periodic function at every overflow.
/// \par
///     The other timers (Timer1 and Timer2) offer all the abilities of
///     Timer0 and many more features.  Both T1 and T2 can operate as
///     general-purpose timers, but T1 has special hardware allowing it to
///     generate PWM signals, while T2 is specially designed to help count
///     out real time (like hours, minutes, seconds).  See the
///     Timer/Counter section of the processor datasheet for more info.
///
//*****************************************************************************
//@{

#ifndef TIMER_H
#define TIMER_H

#include "global.h"

// constants/macros/typdefs

// processor compatibility fixes
#ifdef __AVR_ATmega323__
    // redefinition for the Mega323
    #define CTC1    CTC10
#endif
#ifndef PWM10
    // mega128 PWM bits
    #define PWM10   WGM10
    #define PWM11   WGM11
#endif


// Timer/clock prescaler values and timer overflow rates
// tics = rate at which the timer counts up
// 8bitoverflow = rate at which the timer overflows 8bits (or reaches 256)
// 16bit [overflow] = rate at which the timer overflows 16bits (65536)
// 
// overflows can be used to generate periodic interrupts
//
// for 8MHz crystal
// 0 = STOP (Timer not counting)
// 1 = CLOCK        tics= 8MHz          8bitoverflow= 31250Hz       16bit= 122.070Hz
// 2 = CLOCK/8      tics= 1MHz          8bitoverflow= 3906.25Hz     16bit=  15.259Hz
// 3 = CLOCK/64     tics= 125kHz        8bitoverflow=  488.28Hz     16bit=   1.907Hz
// 4 = CLOCK/256    tics= 31250Hz       8bitoverflow=  122.07Hz     16bit=  0.477Hz
// 5 = CLOCK/1024   tics= 7812.5Hz      8bitoverflow=   30.52Hz     16bit=   0.119Hz
// 6 = External Clock on T(x) pin (falling edge)
// 7 = External Clock on T(x) pin (rising edge)

// for 4MHz crystal
// 0 = STOP (Timer not counting)
// 1 = CLOCK        tics= 4MHz          8bitoverflow= 15625Hz       16bit=  61.035Hz
// 2 = CLOCK/8      tics= 500kHz        8bitoverflow= 1953.125Hz    16bit=   7.629Hz
// 3 = CLOCK/64     tics= 62500Hz       8bitoverflow=  244.141Hz    16bit=   0.954Hz
// 4 = CLOCK/256    tics= 15625Hz       8bitoverflow=   61.035Hz    16bit=   0.238Hz
// 5 = CLOCK/1024   tics= 3906.25Hz     8bitoverflow=   15.259Hz    16bit=   0.060Hz
// 6 = External Clock on T(x) pin (falling edge)
// 7 = External Clock on T(x) pin (rising edge)

// for 3.69MHz crystal
// 0 = STOP (Timer not counting)
// 1 = CLOCK        tics= 3.69MHz       8bitoverflow= 14414Hz       16bit=  56.304Hz
// 2 = CLOCK/8      tics= 461250Hz      8bitoverflow= 1801.758Hz    16bit=   7.038Hz
// 3 = CLOCK/64     tics= 57625.25Hz    8bitoverflow=  225.220Hz    16bit=   0.880Hz
// 4 = CLOCK/256    tics= 14414.063Hz   8bitoverflow=   56.305Hz    16bit=   0.220Hz
// 5 = CLOCK/1024   tics=  3603.516Hz   8bitoverflow=   14.076Hz    16bit=   0.055Hz
// 6 = External Clock on T(x) pin (falling edge)
// 7 = External Clock on T(x) pin (rising edge)

// for 32.768KHz crystal on timer 2 (use for real-time clock)
// 0 = STOP
// 1 = CLOCK        tics= 32.768kHz     8bitoverflow= 128Hz
// 2 = CLOCK/8      tics= 4096kHz       8bitoverflow=  16Hz
// 3 = CLOCK/32     tics= 1024kHz       8bitoverflow=   4Hz
// 4 = CLOCK/64     tics= 512Hz         8bitoverflow=   2Hz
// 5 = CLOCK/128    tics= 256Hz         8bitoverflow=   1Hz
// 6 = CLOCK/256    tics= 128Hz         8bitoverflow=   0.5Hz
// 7 = CLOCK/1024   tics= 32Hz          8bitoverflow=   0.125Hz

#define TIMER_CLK_STOP          0x00    ///< Timer Stopped
#define TIMER_CLK_DIV1          0x01    ///< Timer clocked at F_CPU
#define TIMER_CLK_DIV8          0x02    ///< Timer clocked at F_CPU/8
#define TIMER_CLK_DIV64         0x03    ///< Timer clocked at F_CPU/64
#define TIMER_CLK_DIV256        0x04    ///< Timer clocked at F_CPU/256
#define TIMER_CLK_DIV1024       0x05    ///< Timer clocked at F_CPU/1024
#define TIMER_CLK_T_FALL        0x06    ///< Timer clocked at T falling edge
#define TIMER_CLK_T_RISE        0x07    ///< Timer clocked at T rising edge
#define TIMER_PRESCALE_MASK     0x07    ///< Timer Prescaler Bit-Mask

#define TIMERRTC_CLK_STOP       0x00    ///< RTC Timer Stopped
#define TIMERRTC_CLK_DIV1       0x01    ///< RTC Timer clocked at F_CPU
#define TIMERRTC_CLK_DIV8       0x02    ///< RTC Timer clocked at F_CPU/8
#define TIMERRTC_CLK_DIV32      0x03    ///< RTC Timer clocked at F_CPU/32
#define TIMERRTC_CLK_DIV64      0x04    ///< RTC Timer clocked at F_CPU/64
#define TIMERRTC_CLK_DIV128     0x05    ///< RTC Timer clocked at F_CPU/128
#define TIMERRTC_CLK_DIV256     0x06    ///< RTC Timer clocked at F_CPU/256
#define TIMERRTC_CLK_DIV1024    0x07    ///< RTC Timer clocked at F_CPU/1024
#define TIMERRTC_PRESCALE_MASK  0x07    ///< RTC Timer Prescaler Bit-Mask

// default prescale settings for the timers
// these settings are applied when you call
// timerInit or any of the timer<x>Init
#define TIMER0PRESCALE      TIMER_CLK_DIV8      ///< timer 0 prescaler default
#define TIMER1PRESCALE      TIMER_CLK_DIV64     ///< timer 1 prescaler default
#define TIMER2PRESCALE      TIMERRTC_CLK_DIV64  ///< timer 2 prescaler default

// interrupt macros for attaching user functions to timer interrupts
// use these with timerAttach( intNum, function )
#define TIMER0OVERFLOW_INT          0
#define TIMER1OVERFLOW_INT          1
#define TIMER1OUTCOMPAREA_INT       2
#define TIMER1OUTCOMPAREB_INT       3
#define TIMER1INPUTCAPTURE_INT      4
#define TIMER2OVERFLOW_INT          5
#define TIMER2OUTCOMPARE_INT        6
#ifdef OCR0 // for processors that support output compare on Timer0
#define TIMER0OUTCOMPARE_INT        7
#define TIMER_NUM_INTERRUPTS        8
#else
#define TIMER_NUM_INTERRUPTS        7
#endif

// default type of interrupt handler to use for timers
// *do not change unless you know what you're doing
// Value may be SIGNAL or INTERRUPT
#ifndef TIMER_INTERRUPT_HANDLER
#define TIMER_INTERRUPT_HANDLER     SIGNAL
#endif

// functions
#define delay       delay_us
#define delay_ms    timerPause
void delay_us(unsigned short time_us);

//! initializes timing system (all timers)
// runs all timer init functions
// sets all timers to default prescale values #defined in systimer.c
void timerInit(void);

// default initialization routines for each timer
void timer0Init(void);      ///< initialize timer0
void timer1Init(void);      ///< initialize timer1
#ifdef TCNT2    // support timer2 only if it exists
void timer2Init(void);      ///< initialize timer2
#endif

// Clock prescaler set/get commands for each timer/counter
// For setting the prescaler, you should use one of the #defines
// above like TIMER_CLK_DIVx, where [x] is the division rate
// you want.
// When getting the current prescaler setting, the return value
// will be the [x] division value currently set.
void timer0SetPrescaler(u08 prescale);      ///< set timer0 prescaler
u16  timer0GetPrescaler(void);              ///< get timer0 prescaler
void timer1SetPrescaler(u08 prescale);      ///< set timer1 prescaler
u16  timer1GetPrescaler(void);              ///< get timer0 prescaler
#ifdef TCNT2    // support timer2 only if it exists
void timer2SetPrescaler(u08 prescale);      ///< set timer2 prescaler
u16  timer2GetPrescaler(void);              ///< get timer2 prescaler
#endif


// TimerAttach and Detach commands
//      These functions allow the attachment (or detachment) of any user function
//      to a timer interrupt.  "Attaching" one of your own functions to a timer
//      interrupt means that it will be called whenever that interrupt happens.
//      Using attach is better than rewriting the actual INTERRUPT() function
//      because your code will still work and be compatible if the timer library
//      is updated.  Also, using Attach allows your code and any predefined timer
//      code to work together and at the same time.  (ie. "attaching" your own
//      function to the timer0 overflow doesn't prevent timerPause from working,
//      but rather allows you to share the interrupt.)
//
//      timerAttach(TIMER1OVERFLOW_INT, myOverflowFunction);
//      timerDetach(TIMER1OVERFLOW_INT)
//
//      timerAttach causes the myOverflowFunction() to be attached, and therefore
//      execute, whenever an overflow on timer1 occurs.  timerDetach removes the
//      association and executes no user function when the interrupt occurs.
//      myOverflowFunction must be defined with no return value and no arguments:
//
//      void myOverflowFunction(void) { ... }

//! Attach a user function to a timer interrupt
void timerAttach(u08 interruptNum, void (*userFunc)(void) );
//! Detach a user function from a timer interrupt
void timerDetach(u08 interruptNum);


// timing commands
/// A timer-based delay/pause function
/// @param pause_ms Number of integer milliseconds to wait.
void timerPause(unsigned short pause_ms);

// overflow counters
void timer0ClearOverflowCount(void);    ///< Clear timer0's overflow counter. 
long timer0GetOverflowCount(void);      ///< read timer0's overflow counter
#ifdef TCNT2    // support timer2 only if it exists
void timer2ClearOverflowCount(void);    ///< clear timer2's overflow counter
long timer2GetOverflowCount(void);      ///< read timer0's overflow counter
#endif

/// @defgroup timerpwm Timer PWM Commands
/// @ingroup timer
/// These commands control PWM functionality on timer1
// PWM initialization and set commands for timer1
// timer1PWMInit()
//      configures the timer1 hardware for PWM mode on pins OC1A and OC1B.
//      bitRes should be 8,9,or 10 for 8,9,or 10bit PWM resolution
//
// timer1PWMOff()
//      turns off all timer1 PWM output and set timer mode to normal state
//
// timer1PWMAOn() and timer1PWMBOn()
//      turn on output of PWM signals to OC1A or OC1B pins
//      NOTE: Until you define the OC1A and OC1B pins as outputs, and run
//      this "on" command, no PWM output will be output
//
// timer1PWMAOff() and timer1PWMBOff()
//      turn off output of PWM signals to OC1A or OC1B pins
//
// timer1PWMASet() and timer1PWMBSet()
//      sets the PWM duty cycle for each channel
//  NOTE:   <pwmDuty> should be in the range 0-255 for 8bit PWM
//          <pwmDuty> should be in the range 0-511 for 9bit PWM
//          <pwmDuty> should be in the range 0-1023 for 10bit PWM
// NOTE: the PWM frequency can be controlled in increments by setting the
//          prescaler for timer1
//@{


/// Enter standard PWM Mode on timer1.
/// \param bitRes   indicates the period/resolution to use for PWM output in timer bits.
///                     Must be either 8, 9, or 10 bits corresponding to PWM periods of 256, 512, or 1024 timer tics.
void timer1PWMInit(u08 bitRes);

/// Enter PWM Mode on timer1 with a specific top-count value.
/// \param topcount indicates the desired PWM period in timer tics.
///                     Can be a number between 1 and 65535 (16-bit).
void timer1PWMInitICR(u16 topcount);

/// Turn off all timer1 PWM output and set timer mode to normal.
void timer1PWMOff(void);

/// Turn on/off Timer1 PWM outputs.
void timer1PWMAOn(void);            ///< Turn on timer1 Channel A (OC1A) PWM output.
void timer1PWMBOn(void);            ///< Turn on timer1 Channel B (OC1B) PWM output.
void timer1PWMAOff(void);           ///< turn off timer1 Channel A (OC1A) PWM output
void timer1PWMBOff(void);           ///< turn off timer1 Channel B (OC1B) PWM output

void timer1PWMASet(u16 pwmDuty);    ///< set duty of timer1 Channel A (OC1A) PWM output
void timer1PWMBSet(u16 pwmDuty);    ///< set duty of timer1 Channel B (OC1B) PWM output

//@}
//@}

// Pulse generation commands have been moved to the pulse.c library

#endif

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