#ifndef pwm_timer_h
#define pwm_timer_h

/**
 * \file pwm_timer.h
 * \brief Controls the actual PWM-output.
 * \author Thomas Stegemann
 * \version $Id: pwm_timer.h,v 1.1 2006/09/26 18:18:27 rschaten Exp $
 *
 * License: See documentation.
 *
 * - read and process the pwm_Channels_Message from the messageQueue (written
 *   by pwm_Channels)
 * - use a timed interrupt to switch the led at a specified processor cycle
 * - init starts the processing and the timer
 * - idle is called by the pwm_Channels when the internal buffer is full
 * - at every pwm_timer cycle the leds can be switched in up to four steps
 *   every step defines which leds are switched on/off and up to which
 *   processor cycle the status is hold so the brightness for the three leds
 *   can be switched independently
 * - example:
 *   - start with all leds for 10 cycles:
 *     \code
 *     step[0]= {10, 1|2|4};
 *     \endcode
 *   - switch off the red led for further 10 cycles
 *     \code
 *     step[1]= {20,   2|4};
 *     \endcode
 *   - switch off the green led for further 10 cycles
 *     \code
 *     step[2]= {30,     4};
 *     \endcode
 *   - switch off all leds for the remaining time
 *     \code
 *     step[3]= {pwm_Timer_Cycles_Max, 0};
 *     \endcode
 */

#include "pwm_channels.h"

/** 8-bit-field to contain the state of the channels. */
typedef uint8_t pwm_Channels_Bitfield;

/** Value to count the steps in one channel. */
typedef uint8_t pwm_Channels_StepCounter;

/** Contains a number of controller-cycles. */
typedef uint16_t pwm_Timer_Cycles;

/** Definition of the maximum number of steps. */
enum{pwm_Channels_StepCounter_Max= CHANNELS + 1};

/** Structure to contain one step. */
typedef struct S_pwm_Channels_Step {
    pwm_Timer_Cycles cycle; /**< Number of cycles to complete this step. */
    pwm_Channels_Bitfield field; /**< The state of all channels. */
} pwm_Channels_Step;

/** Structure to contain an array of steps. */
typedef struct S_pwm_Channels_Message {
    pwm_Channels_Step step[pwm_Channels_StepCounter_Max]; /**< Array of steps. */
} pwm_Channels_Message;

void pwm_Timer_init(void);
void pwm_Timer_cleanup(void);
void pwm_Timer_idle(void);

#endif