Servo library tested and debugged.

Some additional HardwareTimer methods introduced to make this
convenient; ancillary libmaple/timers.h changes resulted.

1 files changed, 63 insertions, 21 deletions

diff --git a/libmaple/timers.c b/libmaple/timers.c
index c369d1f..29aeeba 100644
--- a/libmaple/timers.c
+++ b/libmaple/timers.c
@@ -73,16 +73,20 @@ struct timer_dev timer_dev_table[] = {
 /* This function should probably be rewriten to take (timer_num, mode)
  * and have prescaler set elsewhere. The mode can be passed through to
  * set_mode at the end */
-void timer_init(uint8 timer_num, uint16 prescale) {
+void timer_init(timer_dev_num timer_num, uint16 prescale) {
     /* TODO: doesn't catch 6+7 */
-    ASSERT((timer_num != TIMER6) && (timer_num != TIMER7));
 
     timer_port *timer = timer_dev_table[timer_num].base;
     uint8 is_advanced = 0;
 
-    if((timer_num == TIMER1) || (timer_num == TIMER8)) {
+    if (timer_num == TIMER1) {
         is_advanced = 1;
     }
+#if NR_TIMERS >= 8
+    if (timer_num == TIMER8) {
+        is_advanced = 1;
+    }
+#endif
 
     rcc_clk_enable(timer_dev_table[timer_num].rcc_dev_num);
 
@@ -125,48 +129,61 @@ void timer_init(uint8 timer_num, uint16 prescale) {
 }
 
 /* Stops the counter; the mode and settings are not modified */
-void timer_pause(uint8 timer_num) {
+void timer_pause(timer_dev_num timer_num) {
     timer_port *timer = timer_dev_table[timer_num].base;
 
     timer->CR1 &= ~(0x0001);    // CEN
 }
 
 /* Starts the counter; the mode and settings are not modified */
-void timer_resume(uint8 timer_num) {
+void timer_resume(timer_dev_num timer_num) {
     timer_port *timer = timer_dev_table[timer_num].base;
 
     timer->CR1 |= 0x0001;       // CEN
 }
 
+/* Returns the current timer counter value. Probably very inaccurate
+ * if the counter is running with a low prescaler. */
+uint16 timer_get_count(timer_dev_num timer_num) {
+    timer_port *timer = timer_dev_table[timer_num].base;
+
+    return timer->CNT;
+}
+
 /* This function sets the counter value via register for the specified
  * timer.  Can't think of specific usecases except for resetting to
  * zero but it's easy to implement and allows for "creative"
  * programming */
-void timer_set_count(uint8 timer_num, uint16 value) {
+void timer_set_count(timer_dev_num timer_num, uint16 value) {
     timer_port *timer = timer_dev_table[timer_num].base;
 
     timer->CNT = value;
 }
 
-/* Returns the current timer counter value. Probably very inaccurate
- * if the counter is running with a low prescaler. */
-uint16 timer_get_count(uint8 timer_num) {
+/* Get the prescaler buffer value (remember, the actual prescaler
+ * doesn't get set until an update event). */
+uint16 timer_get_prescaler(timer_dev_num timer_num) {
     timer_port *timer = timer_dev_table[timer_num].base;
-
-    return timer->CNT;
+    return timer->PSC;
 }
 
 /* Sets the prescaler */
-void timer_set_prescaler(uint8 timer_num, uint16 prescale) {
+void timer_set_prescaler(timer_dev_num timer_num, uint16 prescale) {
     timer_port *timer = timer_dev_table[timer_num].base;
 
     timer->PSC = prescale;
 }
 
+/* Get the reload value for the entire timer. */
+uint16 timer_get_reload(timer_dev_num timer_num) {
+    timer_port *timer = timer_dev_table[timer_num].base;
+    return timer->ARR;
+}
+
 /* This sets the "reload" or "overflow" value for the entire timer. We
  * should probably settle on either "reload" or "overflow" to prevent
  * confusion? */
-void timer_set_reload(uint8 timer_num, uint16 max_reload) {
+void timer_set_reload(timer_dev_num timer_num, uint16 max_reload) {
     timer_port *timer = timer_dev_table[timer_num].base;
 
     timer->ARR = max_reload;
@@ -211,7 +228,7 @@ void timer_disable_all(void) {
 }
 
 /* Sets the mode of individual timer channels, including a DISABLE mode */
-void timer_set_mode(uint8 timer_num, uint8 channel, TimerMode mode) {
+void timer_set_mode(timer_dev_num timer_num, uint8 channel, TimerMode mode) {
     timer_port *timer = timer_dev_table[timer_num].base;
     ASSERT(channel >= 1);
 
@@ -286,18 +303,36 @@ void timer_set_mode(uint8 timer_num, uint8 channel, TimerMode mode) {
     }
 }
 
+uint16 timer_get_compare_value(timer_dev_num timer_num, uint8 channel_num) {
+    /* faster: just read TIMERx_CHy_CCR (see timers.h) */
+    ASSERT(channel_num > 0 && channel_num <= 4);
+    timer_port *timer = timer_dev_table[timer_num].base;
+    switch(channel_num) {
+    case 1:
+        return timer->CCR1;
+    case 2:
+        return timer->CCR2;
+    case 3:
+        return timer->CCR3;
+    case 4:
+        return timer->CCR4;
+    default:                    /* in case ASSERT is disabled */
+        return 0;
+    }
+}
+
 /* This sets the compare value (aka the trigger) for a given timer
  * channel */
-void timer_set_compare_value(uint8 timer_num,
-                             uint8 compare_num,
+void timer_set_compare_value(timer_dev_num timer_num,
+                             uint8 channel_num,
                              uint16 value) {
+    ASSERT(channel_num > 0 && channel_num <= 4);
+
     /* The faster version of this function is the inline
        timer_pwm_write_ccr */
     timer_port *timer = timer_dev_table[timer_num].base;
 
-    ASSERT(compare_num > 0 && compare_num <= 4);
-
-    switch(compare_num) {
+    switch(channel_num) {
     case 1:
         timer->CCR1 = value;
         break;
@@ -315,7 +350,7 @@ void timer_set_compare_value(uint8 timer_num,
 
 /* Stores a pointer to the passed usercode interrupt function and configures
  * the actual ISR so that it will actually be called */
-void timer_attach_interrupt(uint8 timer_num,
+void timer_attach_interrupt(timer_dev_num timer_num,
                             uint8 compare_num,
                             voidFuncPtr handler) {
     ASSERT(compare_num > 0 && compare_num <= 4);
@@ -327,7 +362,7 @@ void timer_attach_interrupt(uint8 timer_num,
     nvic_irq_enable(timer_dev_table[timer_num].nvic_dev_num);
 }
 
-void timer_detach_interrupt(uint8 timer_num, uint8 compare_num) {
+void timer_detach_interrupt(timer_dev_num timer_num, uint8 compare_num) {
     ASSERT(compare_num > 0 && compare_num <= 4);
 
     timer_port *timer = timer_dev_table[timer_num].base;
@@ -336,6 +371,13 @@ void timer_detach_interrupt(uint8 timer_num, uint8 compare_num) {
     timer->DIER &= ~(1 << compare_num); // 1-indexed compare nums
 }
 
+void timer_generate_update(timer_dev_num timer_num) {
+    /* cause update event by setting UG bit in EGR.  updates prescaler
+       ratio etc. */
+    timer_port *timer = timer_dev_table[timer_num].base;
+    timer->EGR |= 0x1;
+}
+
 /* The following are the actual interrupt handlers; 1 for each timer which must
  * determine which actual compare value (aka channel) was triggered.
  *