Colony

/**

 * Copyright (c) 2007 Colony Project

 *

 * Permission is hereby granted, free of charge, to any person

 * obtaining a copy of this software and associated documentation

 * files (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use,

 * copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following

 * conditions:

 *

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

 * OTHER DEALINGS IN THE SOFTWARE.

 **/

/**

 * @file time.h

 * @brief Contains time-related functions and definitions

 *

 * Contains functions and definitions for dealing with time,

 * namely delay_ms and the realtime clock.

 *

 * @author Colony Project, CMU Robotics Club

 **/

#ifndef _TIME_H_

#define _TIME_H_

/*        Predefined times for prescale_opt in time.c.

        To make you own, know that a pulse is 1/16th of a second. You cannot get less than this. To get more, you need

        to know how many 16ths of a second are in the time you want. (Time_desired * 16 = prescaler_opt)

*/

/**

 * @defgroup time Time

 * @brief Time functions

 *

 * Functions dealing with time.

 *

 * @{

 **/

/** @brief A sixteenth of a second **/

#define SIXTEENTH_SECOND 1

/** @brief An eighth of a second **/

#define EIGTH_SECOND 2

/** @brief A quarter of a second **/

#define QUARTER_SECOND 4

/** @brief Half of a second **/

#define HALF_SECOND        8

/** @brief One second **/

#define SECOND 16

/** @brief Two seconds **/

#define TWO_SECOND 32

/** @brief Four seconds **/

#define FOUR_SECOND 64

/**

 * @brief Delay execution for the specified time

 *

 * Delays for the specified number of milliseconds.

 * It depends on F_CPU to be defined in order to calculate how many cycles

 * it should delay. If it is not defined, a default clock of 8MHz is assumed.

 *

 * We use _delay_loop_2 which will run assembly instructions that should be

 * 4 cycles long. Optimizations must be enabled for this to be true.

 * That function is called to ensure around 1ms per execution. To generate

 * multiple ms we run a for loop of how many milliseconds are desired.

 *

 * The error should be just the skew on the oscillator as the formula to

 * calculate delay cycles should always be a whole number. The is some skew

 * in practice though it is unavoidable. Delaying for less than 1s should make

 * the error negligable.

 *

 * @param ms the number of milliseconds to delay for

 **/

void delay_ms(int ms) ;

/**

 * @brief Enable the realtime clock

 *

 * Initializes the real time clock. Prescales are defined in time.h.

 * For example, SECOND will give 1 second. The specified function is

 * called every clock tick. For the real time clock to activate,

 * interrupts must be enabled. (through sei() )

 *

 * @param prescale_opt the period with which the timer is triggered

 * @param rtc_func the function called when the timer is triggered

 *

 * @see rtc_get, rtc_reset

 *

 **/

void rtc_init(int prescale_opt, void (*rtc_func)(void));

/**

 * @brief Reset the counter of the realtime clock

 *

 * Resets the real time clock counter to 0.

 *

 * @see rtc_init, rtc_get

 **/

void rtc_reset(void);

/**

 * @brief Get the value of the realtime clock.

 *

 * Returns the time elapsed in seconds since the last call to

 * rtc_init or rtc_reset.

 *

 * @return the number of seconds since the last call to rtc_init or rtc_reset

 *

 * @see rtc_init, rtc_reset

 **/

int rtc_get(void);

/** @} **/

#endif