stmhal: Fix timer capture/compare interrupt handling for TIM1 and TIM8.

It turns out that TIM1 and TIM8 have their own Capture/Compare
interrupt vector. For all of the other timers, the capture/compare
interrupt vector is the same as the update vector.

So we need to add handlers for these vectors and enable them
when using capture/compare callbacks.

During testing of this, I also found that passing a channel callback
into the channel constructor would not enable interrupts properly.

I tested using:
```
>>> pyb.Timer(1, freq=4).channel(1, pyb.Timer.OC_TOGGLE, callback=lambda t: print('.', end=''))
```
I tested the above with channels 1, 4, and 8

2 files changed, 38 insertions, 4 deletions

diff --git a/stmhal/stm32_it.c b/stmhal/stm32_it.c
index c9af20ce58..d2f8c271c4 100644
--- a/stmhal/stm32_it.c
+++ b/stmhal/stm32_it.c
@@ -556,6 +556,12 @@ void TIM1_TRG_COM_TIM17_IRQHandler(void) {
 }
 #endif
 
+void TIM1_CC_IRQHandler(void) {
+    IRQ_ENTER(TIM1_CC_IRQn);
+    timer_irq_handler(1);
+    IRQ_EXIT(TIM1_CC_IRQn);
+}
+
 void TIM2_IRQHandler(void) {
     IRQ_ENTER(TIM2_IRQn);
     timer_irq_handler(2);
@@ -581,18 +587,23 @@ void TIM5_IRQHandler(void) {
     IRQ_EXIT(TIM5_IRQn);
 }
 
+#if defined(TIM6) // STM32F401 doesn't have TIM6
 void TIM6_DAC_IRQHandler(void) {
     IRQ_ENTER(TIM6_DAC_IRQn);
     timer_irq_handler(6);
     IRQ_EXIT(TIM6_DAC_IRQn);
 }
+#endif
 
+#if defined(TIM7) // STM32F401 doesn't have TIM7
 void TIM7_IRQHandler(void) {
     IRQ_ENTER(TIM7_IRQn);
     timer_irq_handler(7);
     IRQ_EXIT(TIM7_IRQn);
 }
+#endif
 
+#if defined(TIM8) // STM32F401 doesn't have TIM8
 void TIM8_BRK_TIM12_IRQHandler(void) {
     IRQ_ENTER(TIM8_BRK_TIM12_IRQn);
     timer_irq_handler(12);
@@ -614,11 +625,18 @@ void TIM8_UP_IRQHandler(void) {
 }
 #endif
 
+void TIM8_CC_IRQHandler(void) {
+    IRQ_ENTER(TIM8_CC_IRQn);
+    timer_irq_handler(8);
+    IRQ_EXIT(TIM8_CC_IRQn);
+}
+
 void TIM8_TRG_COM_TIM14_IRQHandler(void) {
     IRQ_ENTER(TIM8_TRG_COM_TIM14_IRQn);
     timer_irq_handler(14);
     IRQ_EXIT(TIM8_TRG_COM_TIM14_IRQn);
 }
+#endif
 
 // UART/USART IRQ handlers
 void USART1_IRQHandler(void) {
diff --git a/stmhal/timer.c b/stmhal/timer.c
index f1f14f3315..e8b29eb97f 100644
--- a/stmhal/timer.c
+++ b/stmhal/timer.c
@@ -603,6 +603,13 @@ STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, mp_uint_t n_args, c
     // set IRQ priority (if not a special timer)
     if (self->tim_id != 3 && self->tim_id != 5) {
         HAL_NVIC_SetPriority(self->irqn, IRQ_PRI_TIMX, IRQ_SUBPRI_TIMX);
+        if (self->tim_id == 1) {
+            HAL_NVIC_SetPriority(TIM1_CC_IRQn, IRQ_PRI_TIMX, IRQ_SUBPRI_TIMX);
+        #if defined(TIM8)
+        } else if (self->tim_id == 8) {
+            HAL_NVIC_SetPriority(TIM8_CC_IRQn, IRQ_PRI_TIMX, IRQ_SUBPRI_TIMX);
+        #endif
+        }
     }
 
     // init TIM
@@ -932,7 +939,7 @@ STATIC mp_obj_t pyb_timer_channel(mp_uint_t n_args, const mp_obj_t *pos_args, mp
             if (chan->callback == mp_const_none) {
                 HAL_TIM_PWM_Start(&self->tim, TIMER_CHANNEL(chan));
             } else {
-                HAL_TIM_PWM_Start_IT(&self->tim, TIMER_CHANNEL(chan));
+                pyb_timer_channel_callback(chan, chan->callback);
             }
             // Start the complimentary channel too (if its supported)
             if (IS_TIM_CCXN_INSTANCE(self->tim.Instance, TIMER_CHANNEL(chan))) {
@@ -970,7 +977,7 @@ STATIC mp_obj_t pyb_timer_channel(mp_uint_t n_args, const mp_obj_t *pos_args, mp
             if (chan->callback == mp_const_none) {
                 HAL_TIM_OC_Start(&self->tim, TIMER_CHANNEL(chan));
             } else {
-                HAL_TIM_OC_Start_IT(&self->tim, TIMER_CHANNEL(chan));
+                pyb_timer_channel_callback(chan, chan->callback);
             }
             // Start the complimentary channel too (if its supported)
             if (IS_TIM_CCXN_INSTANCE(self->tim.Instance, TIMER_CHANNEL(chan))) {
@@ -997,7 +1004,7 @@ STATIC mp_obj_t pyb_timer_channel(mp_uint_t n_args, const mp_obj_t *pos_args, mp
             if (chan->callback == mp_const_none) {
                 HAL_TIM_IC_Start(&self->tim, TIMER_CHANNEL(chan));
             } else {
-                HAL_TIM_IC_Start_IT(&self->tim, TIMER_CHANNEL(chan));
+                pyb_timer_channel_callback(chan, chan->callback);
             }
             break;
         }
@@ -1294,7 +1301,16 @@ STATIC mp_obj_t pyb_timer_channel_callback(mp_obj_t self_in, mp_obj_t callback)
         self->callback = mp_const_none;
     } else if (mp_obj_is_callable(callback)) {
         self->callback = callback;
-        HAL_NVIC_EnableIRQ(self->timer->irqn);
+        uint8_t tim_id = self->timer->tim_id;
+        if (tim_id == 1) {
+            HAL_NVIC_EnableIRQ(TIM1_CC_IRQn);
+        #if defined(TIM8) // STM32F401 doesn't have a TIM8
+        } else if (tim_id == 8) {
+            HAL_NVIC_EnableIRQ(TIM8_CC_IRQn);
+        #endif
+        } else {
+            HAL_NVIC_EnableIRQ(self->timer->irqn);
+        }
         // start timer, so that it interrupts on overflow
         switch (self->mode) {
             case CHANNEL_MODE_PWM_NORMAL: