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Add everytimerb.h
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ATMEGA4809/EveryTimerB.h
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474
ATMEGA4809/EveryTimerB.h
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// EveryTimerB library.
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// by Kees van der Oord Kees.van.der.Oord@inter.nl.net
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// Timer library for the TCB timer of the AtMega4809 processor.
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// tested on the Arduino Nano Every (AtMega4809) and the Arduino 1.8.12 IDE
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// support for the Every is the 'Arduino MegaAVR' boards module (Tools | Board | Boards Manager)
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// usage:
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/*
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#ifdef ARDUINO_ARCH_MEGAAVR
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#include "EveryTimerB.h"
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#define Timer1 TimerB2 // use TimerB2 as a drop in replacement for Timer1
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#else // assume architecture supported by TimerOne library ....
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#include "TimerOne.h"
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#endif
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// code below will now work both on the MegaAVR and AVR processors
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void setup() {
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Timer1.initialize();
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Timer1.attachInterrupt(myisr);
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Timer1.setPeriod(1000000UL); // like the TimerOne library this will start the timer as well
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}
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void myisr() {
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// do something useful every second
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}
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*/
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// clock source options:
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// The TCB clock source is specified in the initialize() function with default value EveryTimerB_CLOCMODE.
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// define this macro before including this file to use a different default clock mode
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// e.g.:
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// #define EveryTimerB_CLOCMODE TCB_CLKSEL_CLKTCA_gc // 250 kHz ~ 4 us
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// #define EveryTimerB_CLOCMODE TCB_CLKSEL_CLKDIV2_gc // 8 MHz ~ 0.125 us
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// #define EveryTimerB_CLOCMODE TCB_CLKSEL_CLKDIV_gc // 16 MHz ~ 0.0625 us
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// timer options
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// The 4809 has one A timer (TCA) and four B timers (TCB).
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// TCA and TCB3 are used by the arduino core to generate the clock used by millis() and micros().
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// TCB0 generates the PWM timing for pin D6, TCB1 for pin D3.
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// By default Timer Control B2 is defined as TimerB2 in the EveryTimerB library.
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// If you would like to use the TCB0 and TCB1 as well you have to copy the code
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// from the EveryTimerB.cpp into your product file and adapt for B0 and B1 timers.
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//
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// for information on the 4809 TCA and TCB timers:
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// http://ww1.microchip.com/downloads/en/AppNotes/TB3217-Getting-Started-with-TCA-90003217A.pdf
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// http://ww1.microchip.com/downloads/en/Appnotes/TB3214-Getting-Started-with-TCB-90003214A.pdf
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// %LOCALAPPDATA%\Arduino15\packages\arduino\hardware\megaavr\1.8.5\cores\arduino\wiring.c
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// %LOCALAPPDATA%\Arduino15\packages\arduino\hardware\megaavr\1.8.5\variants\nona4809\variant.c
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// %LOCALAPPDATA%\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino5\avr\include\avr\iom4809.h
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// 20 MHz system clock
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// to run the Every at 20 MHz, add the lines below to the nona4809 section of the boards.txt file
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// in %LOCALAPPDATA%\Arduino15\packages\arduino\hardware\megaavr\1.8.5.
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// they add the sub menu 'Tools | Clock' to choose between 16MHz and 20MHz.
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/*
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menu.clock=Clock
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nona4809.menu.clock.16internal=16MHz
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nona4809.menu.clock.16internal.build.f_cpu=16000000L
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nona4809.menu.clock.16internal.bootloader.OSCCFG=0x01
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nona4809.menu.clock.20internal=20MHz
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nona4809.menu.clock.20internal.build.f_cpu=20000000L
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nona4809.menu.clock.20internal.bootloader.OSCCFG=0x02
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*/
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// On 20Mhz, the 1.8.12 IDE MegaAvr core library implementation
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// of the millis() and micros() functions is not accurate.
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// the file "MegaAvr20MHz.h" implements a quick hack to correct for this
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//
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// to do:
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// there is no range check on the 'period' arguments of setPeriod ...
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// check if it is necessary to set the CNT register to 0 in start()
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#ifndef EveryTimerB_h_
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#define EveryTimerB_h_
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#ifdef ARDUINO_ARCH_MEGAAVR
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#ifndef EveryTimerB_CLOCMODE
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#define EveryTimerB_CLOCMODE TCB_CLKSEL_CLKTCA_gc
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#endif
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#if defined(ARDUINO) && ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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#include "MegaAvr20MHz.h"
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#include "pins_arduino.h"
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#include "../VirtualTimer.h"
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#define TCB_RESOLUTION 65536UL // TCB is 16 bit
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// CLOCK F_CPU DIV TICK OVERFLOW OVERFLOW/s
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// CLKTCA 16MHz 64 4000 ns 262144us 3.8 Hz
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// CLKDIV2 16MHz 2 125 ns 8192us 122 Hz
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// CLKDIV1 16MHz 1 62.5ns 4096us 244 Hz
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// CLKTCA 20MHz 64 3200 ns 209716us 4.8 Hz
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// CLKDIV2 20MHz 2 100 ns 6554us 153 Hz
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// CLKDIV1 20MHz 1 50 ns 3277us 305 Hz
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class EveryTimerB : public VirtualTimer
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{
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public:
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// The AtMega Timer Control B clock sources selection:
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// TCB_CLKSEL_CLKTCA_gc, // Timer Controller A, Arduino framework sets TCA to F_CPU/64 = 250kHz (4us) @ 16MHz or 312.5kHz (3.2us) @ 20MHz
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// TCB_CLKSEL_CLKDIV2_gc, // CLK_PER/2 Peripheral Clock / 2: 8MHz @ 16Mhz or 10MHz @ 20MHz
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// TCB_CLKSEL_CLKDIV1_gc // CLK_PER Peripheral Clock: 16MHz @ 16Mhz or 20MHz @ 20MHz
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// intialize: sets the timer compare mode and the clock source
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void initialize(TCB_t *timer_ = &TCB2, TCB_CLKSEL_t clockSource = EveryTimerB_CLOCMODE, unsigned long period = 1000000UL) /*__attribute__((always_inline))*/
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{
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timer = timer_;
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#if defined(MegaAvr20MHzCorrected)
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corrected20MHzInit(); // see commment in MegaAvr20MHz_h
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#endif
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stop();
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timer->CTRLB = TCB_CNTMODE_INT_gc & ~TCB_CCMPEN_bm; // timer compare mode with output disabled
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if (clockSource)
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setClockSource(clockSource);
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if (period)
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setPeriod(period);
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}
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void initialize()
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{
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unsigned long period = 1000000UL;
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timer = &TCB2;
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#if defined(MegaAvr20MHzCorrected)
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corrected20MHzInit(); // see commment in MegaAvr20MHz_h
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#endif
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stop();
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timer->CTRLB = TCB_CNTMODE_INT_gc & ~TCB_CCMPEN_bm; // timer compare mode with output disabled
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if (EveryTimerB_CLOCMODE)
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setClockSource(EveryTimerB_CLOCMODE);
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if (period)
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setPeriod(period);
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}
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void setClockSource(TCB_CLKSEL_t clockSource) __attribute__((always_inline))
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{
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timer->CTRLA = clockSource; // this stops the clock as well ...
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switch (clockSource)
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{
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#if F_CPU == 20000000UL
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case TCB_CLKSEL_CLKTCA_gc:
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maxTimeWithoutOverflow = 209715;
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break; // (TCB_RESOLUTION * 64) / 20
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case TCB_CLKSEL_CLKDIV2_gc:
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maxTimeWithoutOverflow = 6553;
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break; // (TCB_RESOLUTION * 2) / 20
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case TCB_CLKSEL_CLKDIV1_gc:
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maxTimeWithoutOverflow = 3276;
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break; // (TCB_RESOLUTION * 1) / 20
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#else
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case TCB_CLKSEL_CLKTCA_gc:
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maxTimeWithoutOverflow = 262144;
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break;
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case TCB_CLKSEL_CLKDIV2_gc:
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maxTimeWithoutOverflow = 8192;
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break;
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case TCB_CLKSEL_CLKDIV1_gc:
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maxTimeWithoutOverflow = 4096;
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break;
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#endif
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}
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}
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TCB_CLKSEL_t getClockSource()
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{
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return (TCB_CLKSEL_t)(timer->CTRLA & (TCB_CLKSEL_CLKTCA_gc | TCB_CLKSEL_CLKDIV2_gc | TCB_CLKSEL_CLKDIV1_gc));
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}
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double getFrequencyOfClock(TCB_CLKSEL_t clock)
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{
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switch (clock)
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{
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// suppose nobody touched the default TCA configuration ...
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case TCB_CLKSEL_CLKTCA_gc:
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return double(F_CPU / 64);
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break;
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case TCB_CLKSEL_CLKDIV2_gc:
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return double(F_CPU / 2);
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break;
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case TCB_CLKSEL_CLKDIV1_gc:
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return double(F_CPU);
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break;
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}
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return 0.0;
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}
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double getClockFrequency()
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{
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return getFrequencyOfClock(getClockSource());
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}
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// setPeriod: sets the period
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// note: max and min values are different for each clock
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// CLKTCA: conversion from us to ticks multiplies 'period' first with 10, so max value is MAX_ULONG/10 ~ 1 hr 11 minutes 34 seconds
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// CLKDIV2: conversion from us to ticks is a *10 multiplication, so max value is 420M us (~ 7 minutes)
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// CLKDIV1: conversion from us to ticks is a *20 multiplication, so max value is 210M us (~ 3.5 minutes)
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void setPeriod(unsigned long period /* us */) /*__attribute__((always_inline))*/
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{
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timer->CTRLA &= ~TCB_ENABLE_bm;
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// conversion from us to ticks depends on the clock
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switch (timer->CTRLA & TCB_CLKSEL_gm)
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{
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case TCB_CLKSEL_CLKTCA_gc:
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#if F_CPU == 20000000UL
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period = (period * 10) / 32; // 20Mhz / 64x clock divider of TCA => 3.2 us / tick
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#else // 16000000UL
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period /= 4; // 16MHz / 64x clock divider of TCA => 4 us / tock
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#endif
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break;
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case TCB_CLKSEL_CLKDIV2_gc:
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#if F_CPU == 20000000UL
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period *= 10; // 20MHz / 2x clock divider => 10 ticks / us
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#else // 16000000UL
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period *= 8; // 16MHz / 2x clock divider => 8 ticks / us
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#endif
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break;
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case TCB_CLKSEL_CLKDIV1_gc:
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#if F_CPU == 20000000UL
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period *= 20; // 20MHz: 20 ticks / us
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#else // 16000000UL
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period *= 16; // 16MHz: 16 ticks / u3
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#endif
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break;
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}
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// to support longer than TCB_RESOLUTION ticks,
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// this class supports first waiting for N 'overflowCounts'
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// and next program the timer the remaining 'remainder' ticks:
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countsPerOverflow = TCB_RESOLUTION;
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overflowCounts = period / TCB_RESOLUTION;
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remainder = period % TCB_RESOLUTION;
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// the timer period is always one tick longer than programmed,
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// so a remainder of 1 is not possible. reduce the length of
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// the 'overflow' cycles to get a remainder that is not 1
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if (overflowCounts)
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{
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while (remainder == 1)
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{
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--countsPerOverflow;
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overflowCounts = period / countsPerOverflow;
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remainder = period % countsPerOverflow;
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}
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}
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// the timer period is always one tick longer than programmed
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--countsPerOverflow;
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if (remainder)
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--remainder;
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// let's go
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start();
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}
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void start() /*__attribute__((always_inline))*/
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{
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stop();
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overflowCounter = overflowCounts;
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timer->CCMP = overflowCounts ? countsPerOverflow : remainder;
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timer->CNT = 0;
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timer->CTRLA |= TCB_ENABLE_bm;
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}
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void stop() /*__attribute__((always_inline))*/
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{
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timer->CTRLA &= ~TCB_ENABLE_bm;
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timer->INTFLAGS = TCB_CAPT_bm; // writing to the INTFLAGS register will clear the interrupt request flag
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}
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bool isEnabled(void) __attribute__((always_inline))
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{
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return timer->CTRLA & TCB_ENABLE_bm ? true : false;
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}
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void enable(void) __attribute__((always_inline))
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{
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timer->CTRLA |= TCB_ENABLE_bm;
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}
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bool disable(void) __attribute__((always_inline))
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{
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timer->CTRLA &= ~TCB_ENABLE_bm;
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}
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void attachInterrupt(void (*isr)()) /*__attribute__((always_inline))*/
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{
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isrCallback = isr;
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timer->INTFLAGS = TCB_CAPT_bm; // clear interrupt request flag
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timer->INTCTRL = TCB_CAPT_bm; // Enable the interrupt
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}
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void attachInterrupt(void (*isr)(), unsigned long microseconds) __attribute__((always_inline))
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{
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if (microseconds > 0)
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stop();
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attachInterrupt(isr);
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if (microseconds > 0)
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setPeriod(microseconds);
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}
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void detachInterrupt() /*__attribute__((always_inline))*/
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{
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timer->INTCTRL &= ~TCB_CAPT_bm; // Disable the interrupt
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isrCallback = isrDefaultUnused;
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}
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void enableInterrupt() __attribute__((always_inline))
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{
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timer->INTFLAGS = TCB_CAPT_bm; // clear interrupt request flag
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timer->INTCTRL = TCB_CAPT_bm; // Enable the interrupt
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}
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void disableInterrupt() __attribute__((always_inline))
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{
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timer->INTCTRL &= ~TCB_CAPT_bm; // Enable the interrupt
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}
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TCB_CNTMODE_enum getMode() __attribute__((always_inline))
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{
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return (TCB_CNTMODE_enum)(timer->CTRLB & 0x7);
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}
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void setMode(TCB_CNTMODE_enum mode) __attribute__((always_inline))
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{
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timer->CTRLB = (timer->CTRLB & ~0x7) | mode;
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}
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uint8_t isOutputEnabled() __attribute__((always_inline))
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{
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return timer->CTRLB & TCB_CCMPEN_bm;
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}
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uint8_t enableOutput() __attribute__((always_inline))
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{
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timer->CTRLB |= TCB_CCMPEN_bm;
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}
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uint8_t disableOutput() __attribute__((always_inline))
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{
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timer->CTRLB &= ~TCB_CCMPEN_bm;
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}
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// this will start PWM on pin 6 (TCB0) or pin 3 (TCB1)
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// set the pins to output with setMode(x,OUTPUT) before calling this function
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// period determines the clock ticks in one cycle:
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// 16MHz clock: slowest frequency at 255 = 62 kHz.
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// 8MHz clock: slowest frequency at 255 = 31 kHz.
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// 256kHz clock: slowest frequency at 255 = 1 kHz.
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// compare determines the duty cycle.
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// with a period of 255, set the compare to 128 to get 50% duty cycle.
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void setPwmMode(byte period, byte compare)
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{
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disableInterrupt();
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setMode(TCB_CNTMODE_PWM8_gc);
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timer->CCMPL = period;
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timer->CCMPH = compare;
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enableOutput();
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enable();
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}
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void getPwmMode(byte &period, byte &compare)
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{
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period = timer->CCMPL;
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compare = timer->CCMPH;
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}
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void setPwm(double frequency, double dutyCycle)
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{
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TCB_CLKSEL_t clockSource = TCB_CLKSEL_CLKDIV1_gc;
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double clockFrequency = getFrequencyOfClock(clockSource);
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if (frequency < (clockFrequency / 256.))
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{
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clockSource = TCB_CLKSEL_CLKDIV2_gc;
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clockFrequency = getFrequencyOfClock(clockSource);
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}
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if (frequency < (clockFrequency / 256.))
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{
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clockSource = TCB_CLKSEL_CLKTCA_gc;
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clockFrequency = getFrequencyOfClock(clockSource);
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}
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double period = (clockFrequency / frequency) - 1.0 + 0.5;
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if (period > 255.)
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period = 255.;
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if (period < 0.)
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period = 0.0;
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double compare = period * dutyCycle + 0.5;
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if (compare < 0.0)
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compare = 0.0;
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if (compare > period)
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compare = period;
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setPwmMode((byte)(period), (byte)(compare));
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}
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void getPwm(double &frequency, double &dutyCycle)
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{
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byte period, compare;
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getPwmMode(period, compare);
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frequency = getClockFrequency() / (((double)period) + 1);
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dutyCycle = (double)compare / (((double)period) + 1);
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}
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void setTimerMode()
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{
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disable();
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disableOutput();
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setMode(TCB_CNTMODE_INT_gc);
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if (isrCallback != isrDefaultUnused)
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{
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enableInterrupt();
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}
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}
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TCB_t *getTimer() { return timer; }
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long getOverflowCounts() { return overflowCounts; }
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long getRemainder() { return remainder; }
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long getOverflowCounter() { return overflowCounter; }
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long getOverflowTime() { return maxTimeWithoutOverflow; }
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//protected:
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// the next_tick function is called by the interrupt service routine TCB0_INT_vect
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//friend extern "C" void TCB0_INT_vect(void);
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void next_tick() __attribute__((always_inline))
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{
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--overflowCounter;
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if (overflowCounter > 0)
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||||
{
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return;
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}
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if (overflowCounter < 0)
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{
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// finished waiting for remainder
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if (overflowCounts)
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{
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// restart with a max counter
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overflowCounter = overflowCounts;
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timer->CCMP = countsPerOverflow;
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||||
}
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}
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else
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||||
{
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// overflowCounter == 0
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||||
// the overflow series has finished: to the remainder if any
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||||
if (remainder)
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{
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timer->CCMP = remainder;
|
||||
if (timer->CNT < remainder)
|
||||
return;
|
||||
// remainder is so short: already passed !
|
||||
timer->CCMP = countsPerOverflow;
|
||||
}
|
||||
// no remainder series: reset the overflow counter and do the callback
|
||||
overflowCounter = overflowCounts;
|
||||
}
|
||||
(*isrCallback)();
|
||||
}
|
||||
|
||||
private:
|
||||
TCB_t *timer = &TCB0;
|
||||
long overflowCounts = 0;
|
||||
long remainder = 10;
|
||||
long overflowCounter = 0;
|
||||
unsigned long countsPerOverflow = TCB_RESOLUTION - 1;
|
||||
void (*isrCallback)();
|
||||
static void isrDefaultUnused();
|
||||
unsigned long maxTimeWithoutOverflow;
|
||||
|
||||
}; // EveryTimerB
|
||||
|
||||
extern EveryTimerB TimerA;
|
||||
|
||||
#endif // ARDUINO_ARCH_MEGAAVR
|
||||
#endif // EveryTimerB_h_
|
||||
126
ATMEGA4809/MegaAvr20Mhz.h
Normal file
126
ATMEGA4809/MegaAvr20Mhz.h
Normal file
|
|
@ -0,0 +1,126 @@
|
|||
#if !defined(MegaAvr20MHz_h_)
|
||||
#define MegaAvr20MHz_h_
|
||||
#if defined(ARDUINO_ARCH_MEGAAVR) && (F_CPU == 20000000UL) && defined(MILLIS_USE_TIMERB3)
|
||||
#define MegaAvr20MHzCorrected
|
||||
// Quick hack to correct the millis() and micros() functions for 20MHz MegaAVR boards.
|
||||
// by Kees van der Oord <Kees.van.der.Oord@inter.nl.net>
|
||||
// Remember to call the function corrected20MHzInit() from setup() or an class constructor !
|
||||
|
||||
// in the IDE 1.8.5 the implementation of millis() and micros() is not accurate
|
||||
// for the MegaAvr achitecture board clocked at 20 MHz:
|
||||
// 1)
|
||||
// in ~\Arduino15\packages\arduino\hardware\megaavr\1.8.5\cores\arduino\wiring.c(386)
|
||||
// microseconds_per_timer_overflow is initialized as:
|
||||
// microseconds_per_timer_overflow = clockCyclesToMicroseconds(TIME_TRACKING_CYCLES_PER_OVF);
|
||||
// this evaluates to (256 * 64) / (20000000/1000000)) = 819.2 which is rounded 819.
|
||||
// the rounding causes millis() and micros() to report times that are 0.2/819.2 = 0.024 % too short
|
||||
// 2)
|
||||
// in ~\Arduino15\packages\arduino\hardware\megaavr\1.8.5\cores\arduino\wiring.c(387)
|
||||
// microseconds_per_timer_tick is defined as:
|
||||
// microseconds_per_timer_tick = microseconds_per_timer_overflow/TIME_TRACKING_TIMER_PERIOD;
|
||||
// which evaluates to 819.2 / 255 = 3.21254901960784 which is rounded to 3
|
||||
// this is wrong in two ways:
|
||||
// - the TIME_TRACKING_TIMER_PERIOD constant is wrong: this should be TIME_TRACKING_TICKS_PER_OVF
|
||||
// so the correct value is 3.2 ns/tick
|
||||
// - the rounding causes micros() to return times that are 0.2/3 = 6.25 % too short
|
||||
// as a quick hack, initialize these variables with settings a factor 5 larger
|
||||
// and redefine the millis() and micros() functions to return the corrected values
|
||||
|
||||
// The code in this header file corrects for these problems by incrementing the counters
|
||||
// with increments that are 5 times larger (the lowest factor that gives integer values).
|
||||
// The millis() and micros() functions are redefined to return the counters / 5.
|
||||
// The costs you pay is that the number of clock cycles of the new millis() and micros()
|
||||
// functions is higher. This should be covered by the fact that the chip runs 25% faster
|
||||
// at 20 MHz than at 16 MHz.
|
||||
|
||||
// This header file redefines the millis() and micros() functions. The redefinition
|
||||
// is only active for source files in which this header file is included. If you link
|
||||
// to libraries with a .cpp file, you have to manually change the library .cpp file to
|
||||
// include this header as well. In addition the corrected20MHzInit() method must be called
|
||||
// from your sketch to re-initialize the variables used by the timer isr function.
|
||||
|
||||
// for micros()
|
||||
// from wiring.c:
|
||||
extern volatile uint32_t timer_overflow_count;
|
||||
|
||||
inline unsigned long corrected_micros() {
|
||||
|
||||
static volatile unsigned long microseconds_offset = 0;
|
||||
|
||||
unsigned long overflows, microseconds;
|
||||
uint8_t ticks;
|
||||
unsigned long offset;
|
||||
|
||||
// Save current state and disable interrupts
|
||||
uint8_t status = SREG;
|
||||
cli();
|
||||
|
||||
// we need to prevent that the double calculation below exceeds MAX_ULONG
|
||||
// this assumes that micros() is called at least once every 35mins)
|
||||
while(timer_overflow_count > 500000UL) {
|
||||
microseconds_offset += 409600000UL; // 500000 * 819.2 ~ almost 7 minutes
|
||||
timer_overflow_count -= 500000UL;
|
||||
}
|
||||
|
||||
// Get current number of overflows and timer count
|
||||
overflows = timer_overflow_count;
|
||||
ticks = TCB3.CNTL;
|
||||
offset = microseconds_offset;
|
||||
|
||||
// If the timer overflow flag is raised, we just missed it,
|
||||
// increment to account for it, & read new ticks
|
||||
if(TCB3.INTFLAGS & TCB_CAPT_bm){
|
||||
overflows++;
|
||||
ticks = TCB3.CNTL;
|
||||
}
|
||||
|
||||
// Restore state
|
||||
SREG = status;
|
||||
|
||||
// Return microseconds of up time (resets every ~70mins)
|
||||
// float aritmic is faster than integer multiplication ?
|
||||
return offset + (unsigned long)((overflows * 819.2) + (ticks * 3.2));
|
||||
}
|
||||
#define micros corrected_micros
|
||||
|
||||
// for millis()
|
||||
// from wiring.c:
|
||||
extern volatile uint32_t timer_millis;
|
||||
extern uint16_t millis_inc;
|
||||
extern uint16_t fract_inc;
|
||||
|
||||
// call this method from your sketch setup() if you include this file !
|
||||
inline void corrected20MHzInit(void) {
|
||||
fract_inc = 96; // (5 * 819.2) % 1000
|
||||
millis_inc = 4; // (5 * 819.2) / 1000
|
||||
}
|
||||
|
||||
inline unsigned long corrected_millis() {
|
||||
static volatile unsigned long last = 0;
|
||||
static volatile unsigned long integer = 0;
|
||||
static volatile unsigned long fraction = 0;
|
||||
|
||||
unsigned long m;
|
||||
|
||||
// disable interrupts while we read timer_millis or we might get an
|
||||
// inconsistent value (e.g. in the middle of a write to timer_millis)
|
||||
uint8_t status = SREG;
|
||||
cli();
|
||||
|
||||
unsigned long elapsed = timer_millis - last;
|
||||
last = timer_millis;
|
||||
integer += elapsed / 5;
|
||||
fraction += elapsed % 5;
|
||||
if(fraction >= 5) { ++integer; fraction -= 5; }
|
||||
|
||||
m = integer;
|
||||
|
||||
SREG = status;
|
||||
|
||||
return m;
|
||||
}
|
||||
#define millis corrected_millis
|
||||
|
||||
#endif // defined(ARDUINO_ARCH_MEGAAVR) && (F_CPU == 20000000UL) && defined(MILLIS_USE_TIMERB3)
|
||||
|
||||
#endif // !defined(MegaAvr20MHz_h_)
|
||||
Loading…
Reference in New Issue
Block a user