Erste CVS-Version

firmware/pwm_timer.h

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+#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
+