git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@2406 35acf78f-673a-0410-8e92-d51de3d6d3f4

os/hal/platforms/STM32/pwm_lld.h

@@ -269,6 +269,23 @@ struct PWMDriver {
 #define PWM_COMPUTE_ARR(pwmclk, pwmperiod)                                  \
   ((uint16_t)(((pwmclk) / (1000000 / (pwmperiod))) - 1))
 
+/**
+ * @brief   Converts from fraction to pulse width.
+ * @note    Be careful with rounding errors, this is integer math not magic.
+ *          You can specify tenths of thousandth but make sure you have the
+ *          proper hardware resolution by carefully choosing the clock source
+ *          and prescaler settings, see @p PWM_COMPUTE_PSC.
+ *
+ * @param[in] numerator numerator of the fraction
+ * @param[in] denominator percentage as an integer between 0 and numerator
+ * @return              The pulse width to be passed to @p pwmEnableChannel().
+ *
+ * @api
+ */
+#define PWM_FRACTION_TO_WIDTH(pwmp, numerator, denominator)                 \
+  ((uint16_t)(((((uint32_t)(pwmp)->pd_config->pc_arr + 1UL) *               \
+                 (uint32_t)(denominator)) / (uint32_t)(numerator)) - 1UL))
+
 /**
  * @brief   Converts from degrees to pulse width.
  * @note    Be careful with rounding errors, this is integer math not magic.
@@ -283,8 +300,7 @@ struct PWMDriver {
  * @api
  */
 #define PWM_DEGREES_TO_WIDTH(pwmp, degrees)                                 \
-  ((uint16_t)(((((uint32_t)(pwmp)->pd_config->pc_arr + 1UL) *               \
+  PWM_FRACTION_TO_WIDTH(pwmp, 36000, degrees)
-                 (uint32_t)(degrees)) / 36000UL) - 1UL))
 
 /**
  * @brief   Converts from percentage to pulse width.
@@ -300,8 +316,7 @@ struct PWMDriver {
  * @api
  */
 #define PWM_PERCENTAGE_TO_WIDTH(pwmp, percentage)                           \
-  ((uint16_t)(((((uint32_t)(pwmp)->pd_config->pc_arr + 1UL) *               \
+  PWM_FRACTION_TO_WIDTH(pwmp, 10000, percentage)
-                 (uint32_t)(percentage)) / 10000UL) - 1UL))
 
 /*===========================================================================*/
 /* External declarations.                                                    */

os/hal/templates/pwm_lld.h

@@ -137,6 +137,21 @@ struct PWMDriver {
 /* Driver macros.                                                            */
 /*===========================================================================*/
 
+/**
+ * @brief   Converts from fraction to pulse width.
+ * @note    Be careful with rounding errors, this is integer math not magic.
+ *          You can specify tenths of thousandth but make sure you have the
+ *          proper hardware resolution by carefully choosing the clock source
+ *          and prescaler settings, see @p PWM_COMPUTE_PSC.
+ *
+ * @param[in] numerator numerator of the fraction
+ * @param[in] denominator percentage as an integer between 0 and numerator
+ * @return              The pulse width to be passed to @p pwmEnableChannel().
+ *
+ * @api
+ */
+#define PWM_FRACTION_TO_WIDTH(pwmp, numerator, denominator) 0
+
 /**
  * @brief   Converts from degrees to pulse width.
  * @note    Be careful with rounding errors, this is integer math not magic.
@@ -150,7 +165,8 @@ struct PWMDriver {
  *
  * @api
  */
-#define PWM_DEGREES_TO_WIDTH(pwmp, degrees) 0
+#define PWM_DEGREES_TO_WIDTH(pwmp, degrees)                                 \
+  PWM_FRACTION_TO_WIDTH(pwmp, 36000, degrees)
 
 /**
  * @brief   Converts from percentage to pulse width.
@@ -165,7 +181,8 @@ struct PWMDriver {
  *
  * @api
  */
-#define PWM_PERCENTAGE_TO_WIDTH(pwmp, percentage) 0
+#define PWM_PERCENTAGE_TO_WIDTH(pwmp, percentage)                           \
+  PWM_FRACTION_TO_WIDTH(pwmp, 10000, percentage)
 
 /*===========================================================================*/
 /* External declarations.                                                    */

readme.txt

@@ -70,6 +70,7 @@
 - FIX: Fixed typo in board name (bug 3113574)(backported to 2.0.7).
 - FIX: Fixed defective event wait functions with timeout (bug 3113443)
   (backported to 2.0.7).
+- NEW: Added new macro PWM_FRACTION_TO_WIDTH() to the PWM driver model.
 - NEW: ARM7 port reorganization following the same pattern of the ARMCMx
   one, on now the port is also supports the ARM9 architecture (but not
   tested yet hardware). Removed the dependencies between the port layer