text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include <stdio.h>
  #include <stdint.h>
  #include <string.h>
  #include <stddef.h>
  
  #include "py/nlr.h"
  #include "py/runtime.h"
  #include "py/gc.h"
  #include "py/mphal.h"
  #include "pin.h"
  #include "reg.h"
  #include "timer.h"
  
  typedef enum {
      CHANNEL_MODE_PWM_NORMAL,
      CHANNEL_MODE_PWM_INVERTED,
      CHANNEL_MODE_OC_TIMING,
      CHANNEL_MODE_OC_ACTIVE,
      CHANNEL_MODE_OC_INACTIVE,
      CHANNEL_MODE_OC_TOGGLE,
  //    CHANNEL_MODE_OC_FORCED_ACTIVE,
  //    CHANNEL_MODE_OC_FORCED_INACTIVE,
      CHANNEL_MODE_IC,
  } pyb_channel_mode;
  
  STATIC const struct {
      qstr        name;
      uint32_t    oc_mode;
  } channel_mode_info[] = {
      { MP_QSTR_PWM,                FTM_OCMODE_PWM1 },
      { MP_QSTR_PWM_INVERTED,       FTM_OCMODE_PWM2 },
      { MP_QSTR_OC_TIMING,          FTM_OCMODE_TIMING },
      { MP_QSTR_OC_ACTIVE,          FTM_OCMODE_ACTIVE },
      { MP_QSTR_OC_INACTIVE,        FTM_OCMODE_INACTIVE },
      { MP_QSTR_OC_TOGGLE,          FTM_OCMODE_TOGGLE },
  //    { MP_QSTR_OC_FORCED_ACTIVE,   FTM_OCMODE_FORCED_ACTIVE },
  //    { MP_QSTR_OC_FORCED_INACTIVE, FTM_OCMODE_FORCED_INACTIVE },
      { MP_QSTR_IC,                 0 },
  };
  
  struct _pyb_timer_obj_t;
  
  typedef struct _pyb_timer_channel_obj_t {
      mp_obj_base_t base;
      struct _pyb_timer_obj_t *timer;
      uint8_t channel;
      uint8_t mode;
      mp_obj_t callback;
      struct _pyb_timer_channel_obj_t *next;
  } pyb_timer_channel_obj_t;
  
  typedef struct _pyb_timer_obj_t {
      mp_obj_base_t base;
      uint8_t tim_id;
      uint8_t irqn;
      mp_obj_t callback;
      FTM_HandleTypeDef ftm;
      pyb_timer_channel_obj_t *channel;
  } pyb_timer_obj_t;
  
  // Used to do callbacks to Python code on interrupt
  STATIC pyb_timer_obj_t *pyb_timer_obj_all[3];
  #define PYB_TIMER_OBJ_ALL_NUM MP_ARRAY_SIZE(pyb_timer_obj_all)
  
  STATIC mp_obj_t pyb_timer_deinit(mp_obj_t self_in);
  STATIC mp_obj_t pyb_timer_callback(mp_obj_t self_in, mp_obj_t callback);
  STATIC mp_obj_t pyb_timer_channel_callback(mp_obj_t self_in, mp_obj_t callback);
  
  void timer_init0(void) {
      for (uint i = 0; i < PYB_TIMER_OBJ_ALL_NUM; i++) {
          pyb_timer_obj_all[i] = NULL;
      }
  }
  
  // unregister all interrupt sources
  void timer_deinit(void) {
      for (uint i = 0; i < PYB_TIMER_OBJ_ALL_NUM; i++) {
          pyb_timer_obj_t *tim = pyb_timer_obj_all[i];
          if (tim != NULL) {
              pyb_timer_deinit(tim);
          }
      }
  }
  
  mp_uint_t get_prescaler_shift(mp_int_t prescaler) {
      mp_uint_t prescaler_shift;
      for (prescaler_shift = 0; prescaler_shift < 8; prescaler_shift++) {
          if (prescaler == (1 << prescaler_shift)) {
              return prescaler_shift;
          }
      }
      nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "prescaler must be a power of 2 between 1 and 128, not %d", prescaler));
  }
  
  /******************************************************************************/
  /* MicroPython bindings                                                       */
  
  STATIC const mp_obj_type_t pyb_timer_channel_type;
  
  // Helper function for determining the period used for calculating percent
  STATIC uint32_t compute_period(pyb_timer_obj_t *self) {
      // In center mode,  compare == period corresponds to 100%
      // In edge mode, compare == (period + 1) corresponds to 100%
      FTM_TypeDef *FTMx = self->ftm.Instance;
      uint32_t period = (FTMx->MOD & 0xffff);
      if ((FTMx->SC & FTM_SC_CPWMS) == 0) {
          // Edge mode
          period++;
      }
      return period;
  }
  
  // Helper function to compute PWM value from timer period and percent value.
  // 'val' can be an int or a float between 0 and 100 (out of range values are
  // clamped).
  STATIC uint32_t compute_pwm_value_from_percent(uint32_t period, mp_obj_t percent_in) {
      uint32_t cmp;
      if (0) {
      #if MICROPY_PY_BUILTINS_FLOAT
      } else if (MP_OBJ_IS_TYPE(percent_in, &mp_type_float)) {
          float percent = mp_obj_get_float(percent_in);
          if (percent <= 0.0) {
              cmp = 0;
          } else if (percent >= 100.0) {
              cmp = period;
          } else {
              cmp = percent / 100.0 * ((float)period);
          }
      #endif
      } else {
          mp_int_t percent = mp_obj_get_int(percent_in);
          if (percent <= 0) {
              cmp = 0;
          } else if (percent >= 100) {
              cmp = period;
          } else {
              cmp = ((uint32_t)percent * period) / 100;
          }
      }
      return cmp;
  }
  
  // Helper function to compute percentage from timer perion and PWM value.
  STATIC mp_obj_t compute_percent_from_pwm_value(uint32_t period, uint32_t cmp) {
      #if MICROPY_PY_BUILTINS_FLOAT
      float percent = (float)cmp * 100.0 / (float)period;
      if (cmp >= period) {
          percent = 100.0;
      } else {
          percent = (float)cmp * 100.0 / (float)period;
      }
      return mp_obj_new_float(percent);
      #else
      mp_int_t percent;
      if (cmp >= period) {
          percent = 100;
      } else {
          percent = cmp * 100 / period;
      }
      return mp_obj_new_int(percent);
      #endif
  }
  
  STATIC void pyb_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
      pyb_timer_obj_t *self = self_in;
  
      if (self->ftm.State == HAL_FTM_STATE_RESET) {
          mp_printf(print, "Timer(%u)", self->tim_id);
      } else {
          mp_printf(print, "Timer(%u, prescaler=%u, period=%u, mode=%s)",
              self->tim_id,
              1 << (self->ftm.Instance->SC & 7),
              self->ftm.Instance->MOD & 0xffff,
              self->ftm.Init.CounterMode == FTM_COUNTERMODE_UP ? "UP" : "CENTER");
      }
  }
  
  /// \method init(*, freq, prescaler, period)
  /// Initialise the timer.  Initialisation must be either by frequency (in Hz)
  /// or by prescaler and period:
  ///
  ///     tim.init(freq=100)                  # set the timer to trigger at 100Hz
  ///     tim.init(prescaler=83, period=999)  # set the prescaler and period directly
  ///
  /// Keyword arguments:
  ///
  ///   - `freq` - specifies the periodic frequency of the timer. You migh also
  ///              view this as the frequency with which the timer goes through
  ///              one complete cycle.
  ///
  ///   - `prescaler` 1, 2, 4, 8 16 32, 64 or 128 - specifies the value to be loaded into the
  ///                 timer's prescaler. The timer clock source is divided by
  ///     (`prescaler`) to arrive at the timer clock.
  ///
  ///   - `period` [0-0xffff] - Specifies the value to be loaded into the timer's
  ///     Modulo Register (MOD). This determines the period of the timer (i.e.
  ///     when the counter cycles). The timer counter will roll-over after
  ///     `period` timer clock cycles. In center mode, a compare register > 0x7fff
  ///     doesn't seem to work properly, so keep this in mind.
  ///
  ///   - `mode` can be one of:
  ///     - `Timer.UP` - configures the timer to count from 0 to MOD (default)
  ///     - `Timer.CENTER` - confgures the timer to count from 0 to MOD and
  ///       then back down to 0.
  ///
  ///   - `callback` - as per Timer.callback()
  ///
  ///  You must either specify freq or both of period and prescaler.
  STATIC const mp_arg_t pyb_timer_init_args[] = {
      { MP_QSTR_freq,             MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0xffffffff} },
      { MP_QSTR_prescaler,        MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0xffffffff} },
      { MP_QSTR_period,           MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0xffffffff} },
      { MP_QSTR_mode,             MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = FTM_COUNTERMODE_UP} },
      { MP_QSTR_callback,         MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
  };
  #define PYB_TIMER_INIT_NUM_ARGS MP_ARRAY_SIZE(pyb_timer_init_args)
  
  STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
      // parse args
      mp_arg_val_t vals[PYB_TIMER_INIT_NUM_ARGS];
      mp_arg_parse_all(n_args, args, kw_args, PYB_TIMER_INIT_NUM_ARGS, pyb_timer_init_args, vals);
  
      FTM_HandleTypeDef *ftm = &self->ftm;
  
      // set the TIM configuration values
      FTM_Base_InitTypeDef *init = &ftm->Init;
  
      if (vals[0].u_int != 0xffffffff) {
          // set prescaler and period from frequency
  
          if (vals[0].u_int == 0) {
              mp_raise_ValueError("can't have 0 frequency");
          }
  
          uint32_t period = MAX(1, F_BUS / vals[0].u_int);
          uint32_t prescaler_shift = 0;
          while (period > 0xffff && prescaler_shift < 7) {
              period >>= 1;
              prescaler_shift++;
          }
          if (period > 0xffff) {
              period = 0xffff;
          }
          init->PrescalerShift = prescaler_shift;
          init->Period = period;
      } else if (vals[1].u_int != 0xffffffff && vals[2].u_int != 0xffffffff) {
          // set prescaler and period directly
          init->PrescalerShift = get_prescaler_shift(vals[1].u_int);
          init->Period = vals[2].u_int;
          if (!IS_FTM_PERIOD(init->Period)) {
              nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "period must be between 0 and 65535, not %d", init->Period));
          }
      } else {
          mp_raise_TypeError("must specify either freq, or prescaler and period");
      }
  
      init->CounterMode = vals[3].u_int;
      if (!IS_FTM_COUNTERMODE(init->CounterMode)) {
          nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "invalid counter mode: %d", init->CounterMode));
      }
  
      // Currently core/mk20dx128.c sets SIM_SCGC6_FTM0, SIM_SCGC6_FTM1, SIM_SCGC3_FTM2
      // so we don't need to do it here.
  
      NVIC_SET_PRIORITY(self->irqn, 0xe); // next-to lowest priority
  
      HAL_FTM_Base_Init(ftm);
      if (vals[4].u_obj == mp_const_none) {
          HAL_FTM_Base_Start(ftm);
      } else {
          pyb_timer_callback(self, vals[4].u_obj);
      }
  
      return mp_const_none;
  }
  
  /// \classmethod \constructor(id, ...)
  /// Construct a new timer object of the given id.  If additional
  /// arguments are given, then the timer is initialised by `init(...)`.
  /// `id` can be 1 to 14, excluding 3.
  STATIC mp_obj_t pyb_timer_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
      // check arguments
      mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
  
      // create new Timer object
      pyb_timer_obj_t *tim = m_new_obj(pyb_timer_obj_t);
      memset(tim, 0, sizeof(*tim));
  
      tim->base.type = &pyb_timer_type;
      tim->callback = mp_const_none;
      tim->channel = NULL;
  
      // get FTM number
      tim->tim_id = mp_obj_get_int(args[0]);
  
      switch (tim->tim_id) {
          case 0: tim->ftm.Instance = FTM0; tim->irqn = IRQ_FTM0; break;
          case 1: tim->ftm.Instance = FTM1; tim->irqn = IRQ_FTM1; break;
          case 2: tim->ftm.Instance = FTM2; tim->irqn = IRQ_FTM2; break;
          default: nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Timer %d does not exist", tim->tim_id));
      }
  
      if (n_args > 1 || n_kw > 0) {
          // start the peripheral
          mp_map_t kw_args;
          mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
          pyb_timer_init_helper(tim, n_args - 1, args + 1, &kw_args);
      }
  
      // set the global variable for interrupt callbacks
      if (tim->tim_id < PYB_TIMER_OBJ_ALL_NUM) {
          pyb_timer_obj_all[tim->tim_id] = tim;
      }
  
      return (mp_obj_t)tim;
  }
  
  STATIC mp_obj_t pyb_timer_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
      return pyb_timer_init_helper(args[0], n_args - 1, args + 1, kw_args);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_timer_init_obj, 1, pyb_timer_init);
  
  /// \method deinit()
  /// Deinitialises the timer.
  ///
  /// Disables the callback (and the associated irq).
  /// Disables any channel callbacks (and the associated irq).
  /// Stops the timer, and disables the timer peripheral.
  STATIC mp_obj_t pyb_timer_deinit(mp_obj_t self_in) {
      pyb_timer_obj_t *self = self_in;
  
      // Disable the base interrupt
      pyb_timer_callback(self_in, mp_const_none);
  
      pyb_timer_channel_obj_t *chan = self->channel;
      self->channel = NULL;
  
      // Disable the channel interrupts
      while (chan != NULL) {
          pyb_timer_channel_callback(chan, mp_const_none);
          pyb_timer_channel_obj_t *prev_chan = chan;
          chan = chan->next;
          prev_chan->next = NULL;
      }
  
      HAL_FTM_Base_DeInit(&self->ftm);
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_timer_deinit_obj, pyb_timer_deinit);
  
  /// \method channel(channel, mode, ...)
  ///
  /// If only a channel number is passed, then a previously initialized channel
  /// object is returned (or `None` if there is no previous channel).
  ///
  /// Othwerwise, a TimerChannel object is initialized and returned.
  ///
  /// Each channel can be configured to perform pwm, output compare, or
  /// input capture. All channels share the same underlying timer, which means
  /// that they share the same timer clock.
  ///
  /// Keyword arguments:
  ///
  ///   - `mode` can be one of:
  ///     - `Timer.PWM` - configure the timer in PWM mode (active high).
  ///     - `Timer.PWM_INVERTED` - configure the timer in PWM mode (active low).
  ///     - `Timer.OC_TIMING` - indicates that no pin is driven.
  ///     - `Timer.OC_ACTIVE` - the pin will be made active when a compare
  ///        match occurs (active is determined by polarity)
  ///     - `Timer.OC_INACTIVE` - the pin will be made inactive when a compare
  ///        match occurs.
  ///     - `Timer.OC_TOGGLE` - the pin will be toggled when an compare match occurs.
  ///     - `Timer.IC` - configure the timer in Input Capture mode.
  ///
  ///   - `callback` - as per TimerChannel.callback()
  ///
  ///   - `pin` None (the default) or a Pin object. If specified (and not None)
  ///           this will cause the alternate function of the the indicated pin
  ///      to be configured for this timer channel. An error will be raised if
  ///      the pin doesn't support any alternate functions for this timer channel.
  ///
  /// Keyword arguments for Timer.PWM modes:
  ///
  ///   - `pulse_width` - determines the initial pulse width value to use.
  ///   - `pulse_width_percent` - determines the initial pulse width percentage to use.
  ///
  /// Keyword arguments for Timer.OC modes:
  ///
  ///   - `compare` - determines the initial value of the compare register.
  ///
  ///   - `polarity` can be one of:
  ///     - `Timer.HIGH` - output is active high
  ///     - `Timer.LOW` - output is acive low
  ///
  /// Optional keyword arguments for Timer.IC modes:
  ///
  ///   - `polarity` can be one of:
  ///     - `Timer.RISING` - captures on rising edge.
  ///     - `Timer.FALLING` - captures on falling edge.
  ///     - `Timer.BOTH` - captures on both edges.
  ///
  /// PWM Example:
  ///
  ///     timer = pyb.Timer(0, prescaler=128, period=37500, counter_mode=pyb.Timer.COUNTER_MODE_CENTER)
  ///     ch0 = t0.channel(0, pyb.Timer.PWM, pin=pyb.Pin.board.D22, pulse_width=(t0.period() + 1) // 4)
  ///     ch1 = t0.channel(1, pyb.Timer.PWM, pin=pyb.Pin.board.D23, pulse_width=(t0.period() + 1) // 2)
  STATIC const mp_arg_t pyb_timer_channel_args[] = {
      { MP_QSTR_callback,            MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
      { MP_QSTR_pin,                 MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
      { MP_QSTR_pulse_width,         MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
      { MP_QSTR_pulse_width_percent, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
      { MP_QSTR_compare,             MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
      { MP_QSTR_polarity,            MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0xffffffff} },
  };
  #define PYB_TIMER_CHANNEL_NUM_ARGS MP_ARRAY_SIZE(pyb_timer_channel_args)
  
  STATIC mp_obj_t pyb_timer_channel(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
      pyb_timer_obj_t *self = args[0];
      mp_int_t channel = mp_obj_get_int(args[1]);
  
      if (channel < 0 || channel > 7) {
          nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Invalid channel (%d)", channel));
      }
  
      pyb_timer_channel_obj_t *chan = self->channel;
      pyb_timer_channel_obj_t *prev_chan = NULL;
  
      while (chan != NULL) {
          if (chan->channel == channel) {
              break;
          }
          prev_chan = chan;
          chan = chan->next;
      }
  
      // If only the channel number is given return the previously allocated
      // channel (or None if no previous channel).
      if (n_args == 2) {
          if (chan) {
              return chan;
          }
          return mp_const_none;
      }
  
      // If there was already a channel, then remove it from the list. Note that
      // the order we do things here is important so as to appear atomic to
      // the IRQ handler.
      if (chan) {
          // Turn off any IRQ associated with the channel.
          pyb_timer_channel_callback(chan, mp_const_none);
  
          // Unlink the channel from the list.
          if (prev_chan) {
              prev_chan->next = chan->next;
          }
          self->channel = chan->next;
          chan->next = NULL;
      }
  
      // Allocate and initialize a new channel
      mp_arg_val_t vals[PYB_TIMER_CHANNEL_NUM_ARGS];
      mp_arg_parse_all(n_args - 3, args + 3, kw_args, PYB_TIMER_CHANNEL_NUM_ARGS, pyb_timer_channel_args, vals);
  
      chan = m_new_obj(pyb_timer_channel_obj_t);
      memset(chan, 0, sizeof(*chan));
      chan->base.type = &pyb_timer_channel_type;
      chan->timer = self;
      chan->channel = channel;
      chan->mode = mp_obj_get_int(args[2]);
      chan->callback = vals[0].u_obj;
  
      mp_obj_t pin_obj = vals[1].u_obj;
      if (pin_obj != mp_const_none) {
          if (!MP_OBJ_IS_TYPE(pin_obj, &pin_type)) {
              mp_raise_ValueError("pin argument needs to be be a Pin type");
          }
          const pin_obj_t *pin = pin_obj;
          const pin_af_obj_t *af = pin_find_af(pin, AF_FN_FTM, self->tim_id);
          if (af == NULL) {
              nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "pin %s doesn't have an af for TIM%d", qstr_str(pin->name), self->tim_id));
          }
          // pin.init(mode=AF_PP, af=idx)
          const mp_obj_t args[6] = {
              (mp_obj_t)&pin_init_obj,
              pin_obj,
              MP_OBJ_NEW_QSTR(MP_QSTR_mode),  MP_OBJ_NEW_SMALL_INT(GPIO_MODE_AF_PP),
              MP_OBJ_NEW_QSTR(MP_QSTR_af),    MP_OBJ_NEW_SMALL_INT(af->idx)
          };
          mp_call_method_n_kw(0, 2, args);
      }
  
      // Link the channel to the timer before we turn the channel on.
      // Note that this needs to appear atomic to the IRQ handler (the write
      // to self->channel is atomic, so we're good, but I thought I'd mention
      // in case this was ever changed in the future).
      chan->next = self->channel;
      self->channel = chan;
  
      switch (chan->mode) {
  
          case CHANNEL_MODE_PWM_NORMAL:
          case CHANNEL_MODE_PWM_INVERTED: {
              FTM_OC_InitTypeDef oc_config;
              oc_config.OCMode = channel_mode_info[chan->mode].oc_mode;
              if (vals[3].u_obj != mp_const_none) {
                  // pulse width ratio given
                  uint32_t period = compute_period(self);
                  oc_config.Pulse = compute_pwm_value_from_percent(period, vals[3].u_obj);
              } else {
                  // use absolute pulse width value (defaults to 0 if nothing given)
                  oc_config.Pulse = vals[2].u_int;
              }
              oc_config.OCPolarity = FTM_OCPOLARITY_HIGH;
  
              HAL_FTM_PWM_ConfigChannel(&self->ftm, &oc_config, channel);
              if (chan->callback == mp_const_none) {
                  HAL_FTM_PWM_Start(&self->ftm, channel);
              } else {
                  HAL_FTM_PWM_Start_IT(&self->ftm, channel);
              }
              break;
          }
  
          case CHANNEL_MODE_OC_TIMING:
          case CHANNEL_MODE_OC_ACTIVE:
          case CHANNEL_MODE_OC_INACTIVE:
          case CHANNEL_MODE_OC_TOGGLE: {
              FTM_OC_InitTypeDef oc_config;
              oc_config.OCMode       = channel_mode_info[chan->mode].oc_mode;
              oc_config.Pulse        = vals[4].u_int;
              oc_config.OCPolarity   = vals[5].u_int;
              if (oc_config.OCPolarity == 0xffffffff) {
                  oc_config.OCPolarity = FTM_OCPOLARITY_HIGH;
              }
  
              if (!IS_FTM_OC_POLARITY(oc_config.OCPolarity)) {
                  nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Invalid polarity (%d)", oc_config.OCPolarity));
              }
              HAL_FTM_OC_ConfigChannel(&self->ftm, &oc_config, channel);
              if (chan->callback == mp_const_none) {
                  HAL_FTM_OC_Start(&self->ftm, channel);
              } else {
                  HAL_FTM_OC_Start_IT(&self->ftm, channel);
              }
              break;
          }
  
          case CHANNEL_MODE_IC: {
              FTM_IC_InitTypeDef ic_config;
  
              ic_config.ICPolarity  = vals[5].u_int;
              if (ic_config.ICPolarity == 0xffffffff) {
                  ic_config.ICPolarity = FTM_ICPOLARITY_RISING;
              }
  
              if (!IS_FTM_IC_POLARITY(ic_config.ICPolarity)) {
                  nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Invalid polarity (%d)", ic_config.ICPolarity));
              }
              HAL_FTM_IC_ConfigChannel(&self->ftm, &ic_config, chan->channel);
              if (chan->callback == mp_const_none) {
                  HAL_FTM_IC_Start(&self->ftm, channel);
              } else {
                  HAL_FTM_IC_Start_IT(&self->ftm, channel);
              }
              break;
          }
  
          default:
              nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Invalid mode (%d)", chan->mode));
      }
  
      return chan;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_timer_channel_obj, 2, pyb_timer_channel);
  
  /// \method counter([value])
  /// Get or set the timer counter.
  STATIC mp_obj_t pyb_timer_counter(size_t n_args, const mp_obj_t *args) {
      pyb_timer_obj_t *self = args[0];
      if (n_args == 1) {
          // get
          return mp_obj_new_int(self->ftm.Instance->CNT);
      }
      // set - In order to write to CNT we need to set CNTIN
      self->ftm.Instance->CNTIN = mp_obj_get_int(args[1]);
      self->ftm.Instance->CNT = 0;    // write any value to load CNTIN into CNT
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_counter_obj, 1, 2, pyb_timer_counter);
  
  /// \method prescaler([value])
  /// Get or set the prescaler for the timer.
  STATIC mp_obj_t pyb_timer_prescaler(size_t n_args, const mp_obj_t *args) {
      pyb_timer_obj_t *self = args[0];
      if (n_args == 1) {
          // get
          return mp_obj_new_int(1 << (self->ftm.Instance->SC & 7));
      }
  
      // set
      mp_uint_t prescaler_shift = get_prescaler_shift(mp_obj_get_int(args[1]));
  
      mp_uint_t sc = self->ftm.Instance->SC;
      sc &= ~7;
      sc |= FTM_SC_PS(prescaler_shift);
      self->ftm.Instance->SC = sc;
  
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_prescaler_obj, 1, 2, pyb_timer_prescaler);
  
  /// \method period([value])
  /// Get or set the period of the timer.
  STATIC mp_obj_t pyb_timer_period(size_t n_args, const mp_obj_t *args) {
      pyb_timer_obj_t *self = args[0];
      if (n_args == 1) {
          // get
          return mp_obj_new_int(self->ftm.Instance->MOD & 0xffff);
      }
  
      // set
      mp_int_t period = mp_obj_get_int(args[1]) & 0xffff;
      self->ftm.Instance->CNT = 0;
      self->ftm.Instance->MOD = period;
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_period_obj, 1, 2, pyb_timer_period);
  
  /// \method callback(fun)
  /// Set the function to be called when the timer triggers.
  /// `fun` is passed 1 argument, the timer object.
  /// If `fun` is `None` then the callback will be disabled.
  STATIC mp_obj_t pyb_timer_callback(mp_obj_t self_in, mp_obj_t callback) {
      pyb_timer_obj_t *self = self_in;
      if (callback == mp_const_none) {
          // stop interrupt (but not timer)
          __HAL_FTM_DISABLE_TOF_IT(&self->ftm);
          self->callback = mp_const_none;
      } else if (mp_obj_is_callable(callback)) {
          self->callback = callback;
          HAL_NVIC_EnableIRQ(self->irqn);
          // start timer, so that it interrupts on overflow
          HAL_FTM_Base_Start_IT(&self->ftm);
      } else {
          mp_raise_ValueError("callback must be None or a callable object");
      }
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_timer_callback_obj, pyb_timer_callback);
  
  #if MICROPY_TIMER_REG
  reg_t timer_reg[] = {
      REG_ENTRY(FTM_TypeDef, SC),
      REG_ENTRY(FTM_TypeDef, CNT),
      REG_ENTRY(FTM_TypeDef, MOD),
      REG_ENTRY(FTM_TypeDef, CNTIN),
      REG_ENTRY(FTM_TypeDef, STATUS),
      REG_ENTRY(FTM_TypeDef, MODE),
      REG_ENTRY(FTM_TypeDef, SYNC),
      REG_ENTRY(FTM_TypeDef, OUTINIT),
      REG_ENTRY(FTM_TypeDef, OUTMASK),
      REG_ENTRY(FTM_TypeDef, COMBINE),
      REG_ENTRY(FTM_TypeDef, DEADTIME),
      REG_ENTRY(FTM_TypeDef, EXTTRIG),
      REG_ENTRY(FTM_TypeDef, POL),
      REG_ENTRY(FTM_TypeDef, FMS),
      REG_ENTRY(FTM_TypeDef, FILTER),
      REG_ENTRY(FTM_TypeDef, FLTCTRL),
      REG_ENTRY(FTM_TypeDef, QDCTRL),
      REG_ENTRY(FTM_TypeDef, CONF),
      REG_ENTRY(FTM_TypeDef, FLTPOL),
      REG_ENTRY(FTM_TypeDef, SYNCONF),
      REG_ENTRY(FTM_TypeDef, INVCTRL),
      REG_ENTRY(FTM_TypeDef, SWOCTRL),
      REG_ENTRY(FTM_TypeDef, PWMLOAD),
  };
  
  mp_obj_t pyb_timer_reg(uint n_args, const mp_obj_t *args) {
      pyb_timer_obj_t *self = args[0];
      return reg_cmd(self->ftm.Instance, timer_reg, MP_ARRAY_SIZE(timer_reg), n_args - 1, args + 1);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_reg_obj, 1, 3, pyb_timer_reg);
  #endif // MICROPY_TIMER_REG
  
  STATIC const mp_rom_map_elem_t pyb_timer_locals_dict_table[] = {
      // instance methods
      { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_timer_init_obj) },
      { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&pyb_timer_deinit_obj) },
      { MP_ROM_QSTR(MP_QSTR_channel), MP_ROM_PTR(&pyb_timer_channel_obj) },
      { MP_ROM_QSTR(MP_QSTR_counter), MP_ROM_PTR(&pyb_timer_counter_obj) },
      { MP_ROM_QSTR(MP_QSTR_prescaler), MP_ROM_PTR(&pyb_timer_prescaler_obj) },
      { MP_ROM_QSTR(MP_QSTR_period), MP_ROM_PTR(&pyb_timer_period_obj) },
      { MP_ROM_QSTR(MP_QSTR_callback), MP_ROM_PTR(&pyb_timer_callback_obj) },
  #if MICROPY_TIMER_REG
      { MP_ROM_QSTR(MP_QSTR_reg), MP_ROM_PTR(&pyb_timer_reg_obj) },
  #endif
      { MP_ROM_QSTR(MP_QSTR_UP),              MP_ROM_INT(FTM_COUNTERMODE_UP) },
      { MP_ROM_QSTR(MP_QSTR_CENTER),          MP_ROM_INT(FTM_COUNTERMODE_CENTER) },
      { MP_ROM_QSTR(MP_QSTR_PWM),             MP_ROM_INT(CHANNEL_MODE_PWM_NORMAL) },
      { MP_ROM_QSTR(MP_QSTR_PWM_INVERTED),    MP_ROM_INT(CHANNEL_MODE_PWM_INVERTED) },
      { MP_ROM_QSTR(MP_QSTR_OC_TIMING),       MP_ROM_INT(CHANNEL_MODE_OC_TIMING) },
      { MP_ROM_QSTR(MP_QSTR_OC_ACTIVE),       MP_ROM_INT(CHANNEL_MODE_OC_ACTIVE) },
      { MP_ROM_QSTR(MP_QSTR_OC_INACTIVE),     MP_ROM_INT(CHANNEL_MODE_OC_INACTIVE) },
      { MP_ROM_QSTR(MP_QSTR_OC_TOGGLE),       MP_ROM_INT(CHANNEL_MODE_OC_TOGGLE) },
      { MP_ROM_QSTR(MP_QSTR_IC),              MP_ROM_INT(CHANNEL_MODE_IC) },
      { MP_ROM_QSTR(MP_QSTR_HIGH),            MP_ROM_INT(FTM_OCPOLARITY_HIGH) },
      { MP_ROM_QSTR(MP_QSTR_LOW),             MP_ROM_INT(FTM_OCPOLARITY_LOW) },
      { MP_ROM_QSTR(MP_QSTR_RISING),          MP_ROM_INT(FTM_ICPOLARITY_RISING) },
      { MP_ROM_QSTR(MP_QSTR_FALLING),         MP_ROM_INT(FTM_ICPOLARITY_FALLING) },
      { MP_ROM_QSTR(MP_QSTR_BOTH),            MP_ROM_INT(FTM_ICPOLARITY_BOTH) },
  };
  STATIC MP_DEFINE_CONST_DICT(pyb_timer_locals_dict, pyb_timer_locals_dict_table);
  
  const mp_obj_type_t pyb_timer_type = {
      { &mp_type_type },
      .name = MP_QSTR_Timer,
      .print = pyb_timer_print,
      .make_new = pyb_timer_make_new,
      .locals_dict = (mp_obj_t)&pyb_timer_locals_dict,
  };
  
  /// \moduleref pyb
  /// \class TimerChannel - setup a channel for a timer.
  ///
  /// Timer channels are used to generate/capture a signal using a timer.
  ///
  /// TimerChannel objects are created using the Timer.channel() method.
  STATIC void pyb_timer_channel_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
      pyb_timer_channel_obj_t *self = self_in;
  
      mp_printf(print, "TimerChannel(timer=%u, channel=%u, mode=%s)",
            self->timer->tim_id,
            self->channel,
            qstr_str(channel_mode_info[self->mode].name));
  }
  
  /// \method capture([value])
  /// Get or set the capture value associated with a channel.
  /// capture, compare, and pulse_width are all aliases for the same function.
  /// capture is the logical name to use when the channel is in input capture mode.
  
  /// \method compare([value])
  /// Get or set the compare value associated with a channel.
  /// capture, compare, and pulse_width are all aliases for the same function.
  /// compare is the logical name to use when the channel is in output compare mode.
  
  /// \method pulse_width([value])
  /// Get or set the pulse width value associated with a channel.
  /// capture, compare, and pulse_width are all aliases for the same function.
  /// pulse_width is the logical name to use when the channel is in PWM mode.
  /// 
  /// In edge aligned mode, a pulse_width of `period + 1` corresponds to a duty cycle of 100%
  /// In center aligned mode, a pulse width of `period` corresponds to a duty cycle of 100%
  STATIC mp_obj_t pyb_timer_channel_capture_compare(size_t n_args, const mp_obj_t *args) {
      pyb_timer_channel_obj_t *self = args[0];
      FTM_TypeDef *FTMx = self->timer->ftm.Instance;
      if (n_args == 1) {
          // get
          return mp_obj_new_int(FTMx->channel[self->channel].CV & 0xffff);
      }
  
      mp_int_t pw = mp_obj_get_int(args[1]);
  
      // set
      FTMx->channel[self->channel].CV = pw & 0xffff;
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_channel_capture_compare_obj, 1, 2, pyb_timer_channel_capture_compare);
  
  /// \method pulse_width_percent([value])
  /// Get or set the pulse width percentage associated with a channel.  The value
  /// is a number between 0 and 100 and sets the percentage of the timer period
  /// for which the pulse is active.  The value can be an integer or
  /// floating-point number for more accuracy.  For example, a value of 25 gives
  /// a duty cycle of 25%.
  STATIC mp_obj_t pyb_timer_channel_pulse_width_percent(size_t n_args, const mp_obj_t *args) {
      pyb_timer_channel_obj_t *self = args[0];
      FTM_TypeDef *FTMx = self->timer->ftm.Instance;
      uint32_t period = compute_period(self->timer);
      if (n_args == 1) {
          // get
          uint32_t cmp = FTMx->channel[self->channel].CV & 0xffff;
          return compute_percent_from_pwm_value(period, cmp);
      } else {
          // set
          uint32_t cmp = compute_pwm_value_from_percent(period, args[1]);
          FTMx->channel[self->channel].CV = cmp & 0xffff;
          return mp_const_none;
      }
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_channel_pulse_width_percent_obj, 1, 2, pyb_timer_channel_pulse_width_percent);
  
  /// \method callback(fun)
  /// Set the function to be called when the timer channel triggers.
  /// `fun` is passed 1 argument, the timer object.
  /// If `fun` is `None` then the callback will be disabled.
  STATIC mp_obj_t pyb_timer_channel_callback(mp_obj_t self_in, mp_obj_t callback) {
      pyb_timer_channel_obj_t *self = self_in;
      if (callback == mp_const_none) {
          // stop interrupt (but not timer)
          __HAL_FTM_DISABLE_CH_IT(&self->timer->ftm, self->channel);
          self->callback = mp_const_none;
      } else if (mp_obj_is_callable(callback)) {
          self->callback = callback;
          HAL_NVIC_EnableIRQ(self->timer->irqn);
          // start timer, so that it interrupts on overflow
          switch (self->mode) {
              case CHANNEL_MODE_PWM_NORMAL:
              case CHANNEL_MODE_PWM_INVERTED:
                  HAL_FTM_PWM_Start_IT(&self->timer->ftm, self->channel);
                  break;
              case CHANNEL_MODE_OC_TIMING:
              case CHANNEL_MODE_OC_ACTIVE:
              case CHANNEL_MODE_OC_INACTIVE:
              case CHANNEL_MODE_OC_TOGGLE:
                  HAL_FTM_OC_Start_IT(&self->timer->ftm, self->channel);
                  break;
              case CHANNEL_MODE_IC:
                  HAL_FTM_IC_Start_IT(&self->timer->ftm, self->channel);
                  break;
          }
      } else {
          mp_raise_ValueError("callback must be None or a callable object");
      }
      return mp_const_none;
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_timer_channel_callback_obj, pyb_timer_channel_callback);
  
  #if MICROPY_TIMER_REG
  reg_t timer_channel_reg[] = {
      REG_ENTRY(FTM_ChannelTypeDef, CSC),
      REG_ENTRY(FTM_ChannelTypeDef, CV),
  };
  
  mp_obj_t pyb_timer_channel_reg(uint n_args, const mp_obj_t *args) {
      pyb_timer_channel_obj_t *self = args[0];
      return reg_cmd(&self->timer->ftm.Instance->channel[self->channel],
                     timer_channel_reg, MP_ARRAY_SIZE(timer_channel_reg),
                     n_args - 1, args + 1);
  }
  STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_channel_reg_obj, 1, 3, pyb_timer_channel_reg);
  #endif
  
  STATIC const mp_rom_map_elem_t pyb_timer_channel_locals_dict_table[] = {
      // instance methods
      { MP_ROM_QSTR(MP_QSTR_callback), MP_ROM_PTR(&pyb_timer_channel_callback_obj) },
      { MP_ROM_QSTR(MP_QSTR_pulse_width), MP_ROM_PTR(&pyb_timer_channel_capture_compare_obj) },
      { MP_ROM_QSTR(MP_QSTR_pulse_width_percent), MP_ROM_PTR(&pyb_timer_channel_pulse_width_percent_obj) },
      { MP_ROM_QSTR(MP_QSTR_capture), MP_ROM_PTR(&pyb_timer_channel_capture_compare_obj) },
      { MP_ROM_QSTR(MP_QSTR_compare), MP_ROM_PTR(&pyb_timer_channel_capture_compare_obj) },
  #if MICROPY_TIMER_REG
      { MP_ROM_QSTR(MP_QSTR_reg), MP_ROM_PTR(&pyb_timer_channel_reg_obj) },
  #endif
  };
  STATIC MP_DEFINE_CONST_DICT(pyb_timer_channel_locals_dict, pyb_timer_channel_locals_dict_table);
  
  STATIC const mp_obj_type_t pyb_timer_channel_type = {
      { &mp_type_type },
      .name = MP_QSTR_TimerChannel,
      .print = pyb_timer_channel_print,
      .locals_dict = (mp_obj_t)&pyb_timer_channel_locals_dict,
  };
  
  STATIC bool ftm_handle_irq_callback(pyb_timer_obj_t *self, mp_uint_t channel, mp_obj_t callback) {
      // execute callback if it's set
      if (callback == mp_const_none) {
          return false;
      }
      bool handled = false;
  
      // When executing code within a handler we must lock the GC to prevent
      // any memory allocations.  We must also catch any exceptions.
      gc_lock();
      nlr_buf_t nlr;
      if (nlr_push(&nlr) == 0) {
          mp_call_function_1(callback, self);
          nlr_pop();
          handled = true;
      } else {
          // Uncaught exception; disable the callback so it doesn't run again.
          self->callback = mp_const_none;
          if (channel == 0xffffffff) {
              printf("Uncaught exception in Timer(" UINT_FMT
                     ") interrupt handler\n", self->tim_id);
          } else {
              printf("Uncaught exception in Timer(" UINT_FMT ") channel "
                     UINT_FMT " interrupt handler\n", self->tim_id, channel);
          }
          mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
      }
      gc_unlock();
      return handled;
  }
  
  STATIC void ftm_irq_handler(uint tim_id) {
      if (tim_id >= PYB_TIMER_OBJ_ALL_NUM) {
          return;
      }
      // get the timer object
      pyb_timer_obj_t *self = pyb_timer_obj_all[tim_id];
      if (self == NULL) {
          // timer object has not been set, so we can't do anything
          printf("No timer object for id=%d\n", tim_id);
          return;
      }
      FTM_HandleTypeDef *hftm = &self->ftm;
  
      bool handled = false;
  
      // Check for timer (versus timer channel) interrupt.
      if (__HAL_FTM_GET_TOF_IT(hftm) && __HAL_FTM_GET_TOF_FLAG(hftm)) {
          __HAL_FTM_CLEAR_TOF_FLAG(hftm);
          if (ftm_handle_irq_callback(self, 0xffffffff, self->callback)) {
              handled = true;
          } else {
              __HAL_FTM_DISABLE_TOF_IT(&self->ftm);
              printf("No callback for Timer %d TOF (now disabled)\n", tim_id);
          }
      }
  
      uint32_t processed = 0;
  
      // Check to see if a timer channel interrupt is pending
      pyb_timer_channel_obj_t *chan = self->channel;
      while (chan != NULL) {
          processed |= (1 << chan->channel);
          if (__HAL_FTM_GET_CH_IT(&self->ftm, chan->channel) && __HAL_FTM_GET_CH_FLAG(&self->ftm, chan->channel)) {
              __HAL_FTM_CLEAR_CH_FLAG(&self->ftm, chan->channel);
              if (ftm_handle_irq_callback(self, chan->channel, chan->callback)) {
                  handled = true;
              } else {
                  __HAL_FTM_DISABLE_CH_IT(&self->ftm, chan->channel);
                  printf("No callback for Timer %d channel %u (now disabled)\n",
                         self->tim_id, chan->channel);
              }
          }
          chan = chan->next;
      }
  
      if (!handled) {
          // An interrupt occurred for a channel we didn't process. Find it and
          // turn it off.
          for (mp_uint_t channel = 0; channel < 8; channel++) {
              if ((processed & (1 << channel)) == 0) {
                  if (__HAL_FTM_GET_CH_FLAG(&self->ftm, channel) != 0) {
                      __HAL_FTM_CLEAR_CH_FLAG(&self->ftm, channel);
                      __HAL_FTM_DISABLE_CH_IT(&self->ftm, channel);
                      printf("Unhandled interrupt Timer %d channel %u (now disabled)\n",
                             tim_id, channel);
                  }
              }
          }
      }
  }
  
  void ftm0_isr(void) {
      ftm_irq_handler(0);
  }
  
  void ftm1_isr(void) {
      ftm_irq_handler(1);
  }
  
  void ftm2_isr(void) {
      ftm_irq_handler(2);
  }
  