118 lines
4.5 KiB
C
118 lines
4.5 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006-2014 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @file AVR/hal_lld.h
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* @brief AVR HAL subsystem low level driver header.
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*
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* @addtogroup HAL
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* @{
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*/
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#ifndef _HAL_LLD_H_
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#define _HAL_LLD_H_
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/*===========================================================================*/
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/* Driver constants. */
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/*===========================================================================*/
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/**
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* @brief Defines the support for realtime counters in the HAL.
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*/
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#define HAL_IMPLEMENTS_COUNTERS FALSE
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/**
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* @brief Platform name.
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*/
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#define PLATFORM_NAME "AVR"
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/**
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* @brief Timer maximum value
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*/
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#define AVR_TIMER_COUNTER_MAX 255
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/*===========================================================================*/
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/* Driver pre-compile time settings. */
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/*===========================================================================*/
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/* Work out what the timer interrupt is called on this MCU */
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#ifdef TIMER0_COMPA_vect
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#define AVR_TIMER_VECT TIMER0_COMPA_vect
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#elif defined(TIMER_COMPA_vect)
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#define AVR_TIMER_VECT TIMER_COMPA_vect
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#elif defined(TIMER0_COMP_vect)
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#define AVR_TIMER_VECT TIMER0_COMP_vect
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#else
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#error "Cannot find interrupt vector name for timer"
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#endif
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/*===========================================================================*/
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/* Derived constants and error checks. */
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/*===========================================================================*/
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/* Find the most suitable prescaler setting for the desired CH_CFG_ST_FREQUENCY */
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#if ((F_CPU / CH_CFG_ST_FREQUENCY) <= AVR_TIMER_COUNTER_MAX)
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#define AVR_TIMER_PRESCALER 1
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#define AVR_TIMER_PRESCALER_BITS (0 << CS02) | (0 << CS01) | (1 << CS00); /* CLK */
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#elif ((F_CPU / CH_CFG_ST_FREQUENCY / 8) <= AVR_TIMER_COUNTER_MAX)
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#define AVR_TIMER_PRESCALER 8
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#define AVR_TIMER_PRESCALER_BITS (0 << CS02) | (1 << CS01) | (0 << CS00); /* CLK/8 */
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#elif ((F_CPU / CH_CFG_ST_FREQUENCY / 64) <= AVR_TIMER_COUNTER_MAX)
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#define AVR_TIMER_PRESCALER 64
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#define AVR_TIMER_PRESCALER_BITS (0 << CS02) | (1 << CS01) | (1 << CS00); /* CLK/64 */
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#elif ((F_CPU / CH_CFG_ST_FREQUENCY / 256) <= AVR_TIMER_COUNTER_MAX)
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#define AVR_TIMER_PRESCALER 256
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#define AVR_TIMER_PRESCALER_BITS (1 << CS02) | (0 << CS01) | (0 << CS00); /* CLK/256 */
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#elif ((F_CPU / CH_CFG_ST_FREQUENCY / 1024) <= AVR_TIMER_COUNTER_MAX)
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#define AVR_TIMER_PRESCALER 1024
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#define AVR_TIMER_PRESCALER_BITS (1 << CS02) | (0 << CS01) | (1 << CS00); /* CLK/1024 */
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#else
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#error "Frequency too low for timer, please set CH_CFG_ST_FREQUENCY to a higher value"
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#endif
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#define AVR_TIMER_COUNTER (F_CPU / CH_CFG_ST_FREQUENCY / AVR_TIMER_PRESCALER)
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/* Test if CH_CFG_ST_FREQUENCY can be matched exactly using this timer */
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#define F_CPU_ (AVR_TIMER_COUNTER * AVR_TIMER_PRESCALER * CH_CFG_ST_FREQUENCY)
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#if (F_CPU_ != F_CPU)
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#warning "CH_CFG_ST_FREQUENCY cannot be generated exactly using timer"
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#endif
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#undef F_CPU_
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/*===========================================================================*/
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/* Driver data structures and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver macros. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* External declarations. */
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/*===========================================================================*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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void hal_lld_init(void);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _HAL_LLD_H_ */
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/** @} */
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