stm32/timer: Expose the PWM BRK capability of Timer 1 and 8.

The break mode is configurable via the 'brk' keyword to the Timer constructor and init method. It's disabled by default.

Author: rolandvs

ports/stm32/timer.c

@@ -112,6 +112,12 @@ STATIC const struct {
  { MP_QSTR_ENC_AB, TIM_ENCODERMODE_TI12 },
 };
 
+enum {
+ BRK_OFF,
+ BRK_LOW,
+ BRK_HIGH,
+};
+
 typedef struct _pyb_timer_channel_obj_t {
  mp_obj_base_t base;
  struct _pyb_timer_obj_t *timer;
@@ -462,14 +468,14 @@ STATIC mp_int_t compute_ticks_from_dtg(uint32_t dtg) {
  return 512 + ((dtg & 0x1F) * 16);
 }
 
-STATIC void config_deadtime(pyb_timer_obj_t *self, mp_int_t ticks) {
+STATIC void config_deadtime(pyb_timer_obj_t *self, mp_int_t ticks, mp_int_t brk) {
  TIM_BreakDeadTimeConfigTypeDef deadTimeConfig;
  deadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
  deadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
  deadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
  deadTimeConfig.DeadTime = compute_dtg_from_ticks(ticks);
- deadTimeConfig.BreakState = TIM_BREAK_DISABLE;
- deadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_LOW;
+ deadTimeConfig.BreakState = brk == BRK_OFF ? TIM_BREAK_DISABLE : TIM_BREAK_ENABLE;
+ deadTimeConfig.BreakPolarity = brk == BRK_LOW ? TIM_BREAKPOLARITY_LOW : TIM_BREAKPOLARITY_HIGH;
  deadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
  HAL_TIMEx_ConfigBreakDeadTime(&self->tim, &deadTimeConfig);
 }
@@ -512,6 +518,12 @@ STATIC void pyb_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_
  {
  mp_printf(print, ", deadtime=%u",
  compute_ticks_from_dtg(self->tim.Instance->BDTR & TIM_BDTR_DTG));
+ if ((self->tim.Instance->BDTR & TIM_BDTR_BKE) == TIM_BDTR_BKE) {
+ mp_printf(print, ", brk=%s",
+ ((self->tim.Instance->BDTR & TIM_BDTR_BKP) == TIM_BDTR_BKP) ? "BRK_HIGH" : "BRK_LOW");
+ } else {
+ mp_printf(print, ", brk=BRK_OFF");
+ }
  }
  mp_print_str(print, ")");
  }
@@ -561,9 +573,15 @@ STATIC void pyb_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_
 /// measures ticks of `source_freq` divided by `div` clock ticks.
 /// `deadtime` is only available on timers 1 and 8.
 ///
+/// - `brk` - specifies if the break mode is used to kill the output of
+/// the PWM when the BRK_IN input is asserted. The polarity set how the
+/// BRK_IN input is triggered. It can be set to `BRK_OFF`, `BRK_LOW`
+/// and `BRK_HIGH`.
+///
+///
 /// You must either specify freq or both of period and prescaler.
 STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
- enum { ARG_freq, ARG_prescaler, ARG_period, ARG_tick_hz, ARG_mode, ARG_div, ARG_callback, ARG_deadtime };
+ enum { ARG_freq, ARG_prescaler, ARG_period, ARG_tick_hz, ARG_mode, ARG_div, ARG_callback, ARG_deadtime, ARG_brk };
  static const mp_arg_t allowed_args[] = {
  { MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
  { MP_QSTR_prescaler, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0xffffffff} },
@@ -573,6 +591,7 @@ STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, size_t n_args, cons
  { MP_QSTR_div, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 1} },
  { MP_QSTR_callback, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
  { MP_QSTR_deadtime, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
+ { MP_QSTR_brk, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = BRK_OFF} },
  };
 
  // parse args
@@ -679,7 +698,8 @@ STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, size_t n_args, cons
  #else
  if (0) {
  #endif
- config_deadtime(self, args[ARG_deadtime].u_int);
+ config_deadtime(self, args[ARG_deadtime].u_int, args[ARG_brk].u_int);
+
  }
 
  // Enable ARPE so that the auto-reload register is buffered.
@@ -1307,6 +1327,9 @@ STATIC const mp_rom_map_elem_t pyb_timer_locals_dict_table[] = {
  { MP_ROM_QSTR(MP_QSTR_RISING), MP_ROM_INT(TIM_ICPOLARITY_RISING) },
  { MP_ROM_QSTR(MP_QSTR_FALLING), MP_ROM_INT(TIM_ICPOLARITY_FALLING) },
  { MP_ROM_QSTR(MP_QSTR_BOTH), MP_ROM_INT(TIM_ICPOLARITY_BOTHEDGE) },
+ { MP_ROM_QSTR(MP_QSTR_BRK_OFF), MP_ROM_INT(BRK_OFF) },
+ { MP_ROM_QSTR(MP_QSTR_BRK_LOW), MP_ROM_INT(BRK_LOW) },
+ { MP_ROM_QSTR(MP_QSTR_BRK_HIGH), MP_ROM_INT(BRK_HIGH) },
 };
 STATIC MP_DEFINE_CONST_DICT(pyb_timer_locals_dict, pyb_timer_locals_dict_table);