/*! \file timer.h \brief System Timer function library. */
//*****************************************************************************
//
// File Name : 'timer.h'
// Title : System Timer function library
// Author : Pascal Stang - Copyright (C) 2000-2002
// Created : 11/22/2000
// Revised : 02/10/2003
// Version : 1.1
// 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 timer Timer Function Library (timer.c)
/// \code #include "timer.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
请教下 红色的那句是怎么处理的，为什么在别的程序中能直接调用呢 |
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