MicroAPRS/bertos/cpu/avr/drv/timer_xmega.c

127 lines
4.5 KiB
C

/**
* \file
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* This file is part of BeRTOS.
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* Copyright 2011 Onno <developer@gorgoz.org>
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* -->
*
* \author Onno <developer@gorgoz.org>
*
* \brief Low-level timer module for AVR XMEGA (implementation).
*
* This file is heavily inspired by the AVR implementation for BeRTOS,
* but uses a different approach for implementing the different debug
* ports, by using the timer structs.
*
* This module is automatically included so no need to include
* in test list.
* notest: all
*/
#include <drv/timer_xmega.h>
#include <cfg/macros.h> // BV()
#include <cpu/types.h>
#include <cpu/irq.h>
#include <avr/io.h>
/* Helper MACROS taken from the Atmel examples and altered
*
* The AVR XMEGA has different structures for TC0 and TC1,
* however these only differ in the amount of compare/capture
* channels, so for this purpose they can be used exactly the same
*/
//check if the bitvalues of the TC0 and TC1 Timer/Counters are really the same
#if TC0_CLKSEL_gm != TC1_CLKSEL_gm || TC0_WGMODE_gm != TC1_WGMODE_gm || TC0_OVFINTLVL_gm != TC1_OVFINTLVL_gm
#error TC0 and TC1 Timer/Counters cannot be configured with the same bitvalues
#endif
#define TIMER_CONFIG_CLOCK_SOURCE(_clkSel)\
((TIMERCOUNTER).CTRLA = ((TIMERCOUNTER).CTRLA & ~TC0_CLKSEL_gm) | _clkSel)
#define TIMER_CLEAR_FLAGS() ((TIMERCOUNTER).INTFLAGS = 0xFF)
#define TIMER_SET_PERIOD( _period ) ( (TIMERCOUNTER).PER = (_period) )
#define TIMER_SET_OVERFLOW_INTERRUPT_LEVEL( _interruptLevel )\
((TIMERCOUNTER).INTCTRLA = ( (TIMERCOUNTER).INTCTRLA & ~TC0_OVFINTLVL_gm ) | _interruptLevel)
#define TIMER_CONFIG_WGM(_wgm)\
((TIMERCOUNTER).CTRLB = ( (TIMERCOUNTER).CTRLB & ~TC0_WGMODE_gm ) | _wgm)
#define TIMER_RESET() ( (TIMERCOUNTER).CTRLFSET = TC_CMD_RESET_gc )
//Define TIMER_PRESCALE_REG_VALUE bases on the provided
//TIMER_PRESCALER value
#if TIMER_PRESCALER == 0
#define TIMER_CLKSEL_gc TC_CLKSEL_OFF_gc
#elif TIMER_PRESCALER == 1
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV1_gc
#elif TIMER_PRESCALER == 2
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV2_gc
#elif TIMER_PRESCALER == 4
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV4_gc
#elif TIMER_PRESCALER == 16
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV16_gc
#elif TIMER_PRESCALER == 64
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV64_gc
#elif TIMER_PRESCALER == 256
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV256_gc
#elif TIMER_PRESCALER == 1024
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV1024_gc
#else
#error Invalid value for TIMER_PRESCALER has been defined! Using default of 1
#define TIMER_CLKSEL_gc TC_CLKSEL_DIV1_gc
#endif
void timer_hw_init(void)
{
//Save and disable IRQ
cpu_flags_t flags;
IRQ_SAVE_DISABLE(flags);
//disable the timer
TIMER_CONFIG_CLOCK_SOURCE(TC_CLKSEL_OFF_gc);
//clear all flags
TIMER_CLEAR_FLAGS();
//setup the Periode register value
//CNT register will be reset to 0 when CNT == PER
TIMER_SET_PERIOD(TIMER_PERIOD_VALUE);
//set the Waveform Generation Mode to Normal
TIMER_CONFIG_WGM(TC_WGMODE_NORMAL_gc);
//enable the overflow interrupt
//use the highest priority
TIMER_SET_OVERFLOW_INTERRUPT_LEVEL(TC_OVFINTLVL_HI_gc);
//enable timer by setting the correct prescaler/clock
TIMER_CONFIG_CLOCK_SOURCE(TIMER_CLKSEL_gc);
//Restore IRQ
IRQ_RESTORE(flags);
}