stmhal/timer.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the Micro Python 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 <stdint.h>
 #include <stdio.h>
 #include <string.h>

 #include <stm32f4xx_hal.h>
 #include "usbd_cdc_msc_hid.h"
 #include "usbd_cdc_interface.h"

 #include "nlr.h"
 #include "misc.h"
 #include "mpconfig.h"
 #include "qstr.h"
 #include "gc.h"
 #include "obj.h"
 #include "runtime.h"
 #include "timer.h"
 #include "servo.h"

 /// \moduleref pyb
 /// \class Timer - periodically call a function
 ///
 /// Timers can be used for a great variety of tasks.  At the moment, only
 /// the simplest case is implemented: that of calling a function periodically.
 ///
 /// Each timer consists of a counter that counts up at a certain rate.  The rate
 /// at which it counts is the peripheral clock frequency (in Hz) divided by the
 /// timer prescaler.  When the counter reaches the timer period it triggers an
 /// event, and the counter resets back to zero.  By using the callback method,
 /// the timer event can call a Python function.
 ///
 /// Example usage to toggle an LED at a fixed frequency:
 ///
 ///     tim = pyb.Timer(4)              # create a timer object using timer 4
 ///     tim.init(freq=2)                # trigger at 2Hz
 ///     tim.callback(lambda t:pyb.LED(1).toggle())
 ///
 /// Further examples:
 ///
 ///     tim = pyb.Timer(4, freq=100)    # freq in Hz
 ///     tim = pyb.Timer(4, prescaler=1, period=100)
 ///     tim.counter()                   # get counter (can also set)
 ///     tim.prescaler(2)                # set prescaler (can also get)
 ///     tim.period(200)                 # set period (can also get)
 ///     tim.callback(lambda t: ...)     # set callback for update interrupt (t=tim instance)
 ///     tim.callback(None)              # clear callback
 ///
 /// *Note:* Timer 3 is reserved for internal use.  Timer 5 controls
 /// the servo driver, and Timer 6 is used for timed ADC/DAC reading/writing.
 /// It is recommended to use the other timers in your programs.

 // The timers can be used by multiple drivers, and need a common point for
 // the interrupts to be dispatched, so they are all collected here.
 //
 // TIM3:
 //  - flash storage controller, to flush the cache
 //  - USB CDC interface, interval, to check for new data
 //  - LED 4, PWM to set the LED intensity
 //
 // TIM5:
 //  - servo controller, PWM
 //
 // TIM6:
 //  - ADC, DAC for read_timed and write_timed

 typedef struct _pyb_timer_obj_t {
     mp_obj_base_t base;
     machine_uint_t tim_id;
     mp_obj_t callback;
     TIM_HandleTypeDef tim;
     IRQn_Type irqn;
 } pyb_timer_obj_t;

 TIM_HandleTypeDef TIM3_Handle;
 TIM_HandleTypeDef TIM5_Handle;
 TIM_HandleTypeDef TIM6_Handle;

 // Used to divide down TIM3 and periodically call the flash storage IRQ
 static uint32_t tim3_counter = 0;

 // Used to do callbacks to Python code on interrupt
 STATIC pyb_timer_obj_t *pyb_timer_obj_all[14];
 #define PYB_TIMER_OBJ_ALL_NUM ARRAY_SIZE(pyb_timer_obj_all)

 void timer_init0(void) {
     tim3_counter = 0;
     for (uint i = 0; i < PYB_TIMER_OBJ_ALL_NUM; i++) {
         pyb_timer_obj_all[i] = NULL;
     }
 }

 // TIM3 is set-up for the USB CDC interface
 void timer_tim3_init(void) {
     // set up the timer for USBD CDC
     __TIM3_CLK_ENABLE();

     TIM3_Handle.Instance = TIM3;
     TIM3_Handle.Init.Period = (USBD_CDC_POLLING_INTERVAL*1000) - 1; // TIM3 fires every USBD_CDC_POLLING_INTERVAL ms
     TIM3_Handle.Init.Prescaler = 84-1; // for System clock at 168MHz, TIM3 runs at 1MHz
     TIM3_Handle.Init.ClockDivision = 0;
     TIM3_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
     HAL_TIM_Base_Init(&TIM3_Handle);

     HAL_NVIC_SetPriority(TIM3_IRQn, 6, 0);
     HAL_NVIC_EnableIRQ(TIM3_IRQn);

     if (HAL_TIM_Base_Start(&TIM3_Handle) != HAL_OK) {
         /* Starting Error */
     }
 }

 /* unused
 void timer_tim3_deinit(void) {
     // reset TIM3 timer
     __TIM3_FORCE_RESET();
     __TIM3_RELEASE_RESET();
 }
 */

 // TIM5 is set-up for the servo controller
 // This function inits but does not start the timer
 void timer_tim5_init(void) {
     // TIM5 clock enable
     __TIM5_CLK_ENABLE();

     // set up and enable interrupt
     HAL_NVIC_SetPriority(TIM5_IRQn, 6, 0);
     HAL_NVIC_EnableIRQ(TIM5_IRQn);

     // PWM clock configuration
     TIM5_Handle.Instance = TIM5;
     TIM5_Handle.Init.Period = 2000; // timer cycles at 50Hz
     TIM5_Handle.Init.Prescaler = ((SystemCoreClock / 2) / 100000) - 1; // timer runs at 100kHz
     TIM5_Handle.Init.ClockDivision = 0;
     TIM5_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
     HAL_TIM_PWM_Init(&TIM5_Handle);
 }

 // Init TIM6 with a counter-overflow at the given frequency (given in Hz)
 // TIM6 is used by the DAC and ADC for auto sampling at a given frequency
 // This function inits but does not start the timer
 void timer_tim6_init(uint freq) {
     // TIM6 clock enable
     __TIM6_CLK_ENABLE();

     // Timer runs at SystemCoreClock / 2
     // Compute the prescaler value so TIM6 triggers at freq-Hz
     uint32_t period = MAX(1, (SystemCoreClock / 2) / freq);
     uint32_t prescaler = 1;
     while (period > 0xffff) {
         period >>= 1;
         prescaler <<= 1;
     }

     // Time base clock configuration
     TIM6_Handle.Instance = TIM6;
     TIM6_Handle.Init.Period = period - 1;
     TIM6_Handle.Init.Prescaler = prescaler - 1;
     TIM6_Handle.Init.ClockDivision = 0; // unused for TIM6
     TIM6_Handle.Init.CounterMode = TIM_COUNTERMODE_UP; // unused for TIM6
     HAL_TIM_Base_Init(&TIM6_Handle);
 }

 // Interrupt dispatch
 void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
     if (htim == &TIM3_Handle) {
         USBD_CDC_HAL_TIM_PeriodElapsedCallback();

         // Periodically raise a flash IRQ for the flash storage controller
         if (tim3_counter++ >= 500 / USBD_CDC_POLLING_INTERVAL) {
             tim3_counter = 0;
             NVIC->STIR = FLASH_IRQn;
         }

     } else if (htim == &TIM5_Handle) {
         servo_timer_irq_callback();
     }
 }

 /******************************************************************************/
 /* Micro Python bindings                                                      */

 STATIC void pyb_timer_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_timer_obj_t *self = self_in;

     if (self->tim.State == HAL_TIM_STATE_RESET) {
         print(env, "Timer(%u)", self->tim_id);
     } else {
         print(env, "Timer(%u, prescaler=%u, period=%u, mode=%u, div=%u)",
             self->tim_id,
             self->tim.Init.Prescaler,
             self->tim.Init.Period,
             self->tim.Init.CounterMode,
             self->tim.Init.ClockDivision
         );
     }
 }

 /// \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=100, period=300) # set the prescaler and period directly
 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 = TIM_COUNTERMODE_UP} },
     { MP_QSTR_div,       MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = TIM_CLOCKDIVISION_DIV1} },
 };
 #define PYB_TIMER_INIT_NUM_ARGS 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);

     // set the TIM configuration values
     TIM_Base_InitTypeDef *init = &self->tim.Init;

     if (vals[0].u_int != 0xffffffff) {
         // set prescaler and period from frequency

         if (vals[0].u_int == 0) {
             nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "can't have 0 frequency"));
         }

         // work out TIM's clock source
         uint tim_clock;
         if (self->tim_id == 1 || (8 <= self->tim_id && self->tim_id <= 11)) {
             // TIM{1,8,9,10,11} are on APB2
             tim_clock = HAL_RCC_GetPCLK2Freq();
         } else {
             // TIM{2,3,4,5,6,7,12,13,14} are on APB1
             tim_clock = HAL_RCC_GetPCLK1Freq();
         }

         // compute the prescaler value so TIM triggers at freq-Hz
         // dpgeorge: I don't understand why we need to multiply tim_clock by 2
         uint32_t period = MAX(1, 2 * tim_clock / vals[0].u_int);
         uint32_t prescaler = 1;
         while (period > 0xffff) {
             period >>= 1;
             prescaler <<= 1;
         }
         init->Prescaler = prescaler - 1;
         init->Period = period - 1;
     } else if (vals[1].u_int != 0xffffffff && vals[2].u_int != 0xffffffff) {
         // set prescaler and period directly
         init->Prescaler = vals[1].u_int;
         init->Period = vals[2].u_int;
     } else {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "must specify either freq, or prescaler and period"));
     }

     init->CounterMode = vals[3].u_int;
     init->ClockDivision = vals[4].u_int;
     init->RepetitionCounter = 0;

     // init the TIM peripheral
     switch (self->tim_id) {
         case 1: __TIM1_CLK_ENABLE(); break;
         case 2: __TIM2_CLK_ENABLE(); break;
         case 3: __TIM3_CLK_ENABLE(); break;
         case 4: __TIM4_CLK_ENABLE(); break;
         case 5: __TIM5_CLK_ENABLE(); break;
         case 6: __TIM6_CLK_ENABLE(); break;
         case 7: __TIM7_CLK_ENABLE(); break;
         case 8: __TIM8_CLK_ENABLE(); break;
         case 9: __TIM9_CLK_ENABLE(); break;
         case 10: __TIM10_CLK_ENABLE(); break;
         case 11: __TIM11_CLK_ENABLE(); break;
         case 12: __TIM12_CLK_ENABLE(); break;
         case 13: __TIM13_CLK_ENABLE(); break;
         case 14: __TIM14_CLK_ENABLE(); break;
     }
     HAL_TIM_Base_Init(&self->tim);
     HAL_TIM_Base_Start(&self->tim);

     // set the priority (if not a special timer)
     if (self->tim_id != 3 && self->tim_id != 5) {
         HAL_NVIC_SetPriority(self->irqn, 0xe, 0xe); // next-to lowest priority
     }

     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(mp_obj_t type_in, uint n_args, uint 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);
     tim->base.type = &pyb_timer_type;
     tim->callback = mp_const_none;
     memset(&tim->tim, 0, sizeof(tim->tim));

     // get TIM number
     tim->tim_id = mp_obj_get_int(args[0]);

     switch (tim->tim_id) {
         case 1: tim->tim.Instance = TIM1; tim->irqn = TIM1_UP_TIM10_IRQn; break;
         case 2: tim->tim.Instance = TIM2; tim->irqn = TIM2_IRQn; break;
         case 3: nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "Timer 3 is for internal use only")); // TIM3 used for low-level stuff; go via regs if necessary
         case 4: tim->tim.Instance = TIM4; tim->irqn = TIM4_IRQn; break;
         case 5: tim->tim.Instance = TIM5; tim->irqn = TIM5_IRQn; break;
         case 6: tim->tim.Instance = TIM6; tim->irqn = TIM6_DAC_IRQn; break;
         case 7: tim->tim.Instance = TIM7; tim->irqn = TIM7_IRQn; break;
         case 8: tim->tim.Instance = TIM8; tim->irqn = TIM8_UP_TIM13_IRQn; break;
         case 9: tim->tim.Instance = TIM9; tim->irqn = TIM1_BRK_TIM9_IRQn; break;
         case 10: tim->tim.Instance = TIM10; tim->irqn = TIM1_UP_TIM10_IRQn; break;
         case 11: tim->tim.Instance = TIM11; tim->irqn = TIM1_TRG_COM_TIM11_IRQn; break;
         case 12: tim->tim.Instance = TIM12; tim->irqn = TIM8_BRK_TIM12_IRQn; break;
         case 13: tim->tim.Instance = TIM13; tim->irqn = TIM8_UP_TIM13_IRQn; break;
         case 14: tim->tim.Instance = TIM14; tim->irqn = TIM8_TRG_COM_TIM14_IRQn; 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 - 1 < PYB_TIMER_OBJ_ALL_NUM) {
         pyb_timer_obj_all[tim->tim_id - 1] = tim;
     }

     return (mp_obj_t)tim;
 }

 STATIC mp_obj_t pyb_timer_init(uint 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.
 ///
 /// *This function is not yet implemented.*
 STATIC mp_obj_t pyb_timer_deinit(mp_obj_t self_in) {
     //pyb_timer_obj_t *self = self_in;
     // TODO implement me
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_timer_deinit_obj, pyb_timer_deinit);

 /// \method counter([value])
 /// Get or set the timer counter.
 mp_obj_t pyb_timer_counter(uint 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->tim.Instance->CNT);
     } else {
         // set
         __HAL_TIM_SetCounter(&self->tim, mp_obj_get_int(args[1]));
         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.
 mp_obj_t pyb_timer_prescaler(uint 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->tim.Instance->PSC & 0xffff);
     } else {
         // set
         self->tim.Init.Prescaler = self->tim.Instance->PSC = mp_obj_get_int(args[1]) & 0xffff;
         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.
 mp_obj_t pyb_timer_period(uint 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->tim.Instance->ARR & 0xffff);
     } else {
         // set
         __HAL_TIM_SetAutoreload(&self->tim, mp_obj_get_int(args[1]) & 0xffff);
         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_TIM_DISABLE_IT(&self->tim, TIM_IT_UPDATE);
         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_TIM_Base_Start_IT(&self->tim);
     } else {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_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);

 STATIC const mp_map_elem_t pyb_timer_locals_dict_table[] = {
     // instance methods
     { MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&pyb_timer_init_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_timer_deinit_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_counter), (mp_obj_t)&pyb_timer_counter_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_prescaler), (mp_obj_t)&pyb_timer_prescaler_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_period), (mp_obj_t)&pyb_timer_period_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_callback), (mp_obj_t)&pyb_timer_callback_obj },
 };

 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,
 };

 void timer_irq_handler(uint tim_id) {
     if (tim_id - 1 < PYB_TIMER_OBJ_ALL_NUM) {
         // get the timer object
         pyb_timer_obj_t *tim = pyb_timer_obj_all[tim_id - 1];

         if (tim == NULL) {
             // timer object has not been set, so we can't do anything
             return;
         }

         // see if it was a TIM update event (the only event we currently interrupt on)
         if (__HAL_TIM_GET_FLAG(&tim->tim, TIM_FLAG_UPDATE) != RESET) {
             if (__HAL_TIM_GET_ITSTATUS(&tim->tim, TIM_IT_UPDATE) != RESET) {
                 // clear the interrupt
                 __HAL_TIM_CLEAR_IT(&tim->tim, TIM_IT_UPDATE);

                 // execute callback if it's set
                 if (tim->callback != mp_const_none) {
                     // 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(tim->callback, tim);
                         nlr_pop();
                     } else {
                         // Uncaught exception; disable the callback so it doesn't run again.
                         tim->callback = mp_const_none;
                         __HAL_TIM_DISABLE_IT(&tim->tim, TIM_IT_UPDATE);
                         printf("Uncaught exception in Timer(" UINT_FMT ") interrupt handler\n", tim->tim_id);
                         mp_obj_print_exception((mp_obj_t)nlr.ret_val);
                     }
                     gc_unlock();
                 }
             }
         }
     }
 }
	/*
	* This file is part of the Micro Python 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 <stdint.h>
	#include <stdio.h>
	#include <string.h>

	#include <stm32f4xx_hal.h>
	#include "usbd_cdc_msc_hid.h"
	#include "usbd_cdc_interface.h"

	#include "nlr.h"
	#include "misc.h"
	#include "mpconfig.h"
	#include "qstr.h"
	#include "gc.h"
	#include "obj.h"
	#include "runtime.h"
	#include "timer.h"
	#include "servo.h"

	/// \moduleref pyb
	/// \class Timer - periodically call a function
	///
	/// Timers can be used for a great variety of tasks. At the moment, only
	/// the simplest case is implemented: that of calling a function periodically.
	///
	/// Each timer consists of a counter that counts up at a certain rate. The rate
	/// at which it counts is the peripheral clock frequency (in Hz) divided by the
	/// timer prescaler. When the counter reaches the timer period it triggers an
	/// event, and the counter resets back to zero. By using the callback method,
	/// the timer event can call a Python function.
	///
	/// Example usage to toggle an LED at a fixed frequency:
	///
	/// tim = pyb.Timer(4) # create a timer object using timer 4
	/// tim.init(freq=2) # trigger at 2Hz
	/// tim.callback(lambda t:pyb.LED(1).toggle())
	///
	/// Further examples:
	///
	/// tim = pyb.Timer(4, freq=100) # freq in Hz
	/// tim = pyb.Timer(4, prescaler=1, period=100)
	/// tim.counter() # get counter (can also set)
	/// tim.prescaler(2) # set prescaler (can also get)
	/// tim.period(200) # set period (can also get)
	/// tim.callback(lambda t: ...) # set callback for update interrupt (t=tim instance)
	/// tim.callback(None) # clear callback
	///
	/// Note: Timer 3 is reserved for internal use. Timer 5 controls
	/// the servo driver, and Timer 6 is used for timed ADC/DAC reading/writing.
	/// It is recommended to use the other timers in your programs.

	// The timers can be used by multiple drivers, and need a common point for
	// the interrupts to be dispatched, so they are all collected here.
	//
	// TIM3:
	// - flash storage controller, to flush the cache
	// - USB CDC interface, interval, to check for new data
	// - LED 4, PWM to set the LED intensity
	//
	// TIM5:
	// - servo controller, PWM
	//
	// TIM6:
	// - ADC, DAC for read_timed and write_timed

	typedef struct _pyb_timer_obj_t {
	mp_obj_base_t base;
	machine_uint_t tim_id;
	mp_obj_t callback;
	TIM_HandleTypeDef tim;
	IRQn_Type irqn;
	} pyb_timer_obj_t;

	TIM_HandleTypeDef TIM3_Handle;
	TIM_HandleTypeDef TIM5_Handle;
	TIM_HandleTypeDef TIM6_Handle;

	// Used to divide down TIM3 and periodically call the flash storage IRQ
	static uint32_t tim3_counter = 0;

	// Used to do callbacks to Python code on interrupt
	STATIC pyb_timer_obj_t *pyb_timer_obj_all[14];
	#define PYB_TIMER_OBJ_ALL_NUM ARRAY_SIZE(pyb_timer_obj_all)

	void timer_init0(void) {
	tim3_counter = 0;
	for (uint i = 0; i < PYB_TIMER_OBJ_ALL_NUM; i++) {
	pyb_timer_obj_all[i] = NULL;
	}
	}

	// TIM3 is set-up for the USB CDC interface
	void timer_tim3_init(void) {
	// set up the timer for USBD CDC
	__TIM3_CLK_ENABLE();

	TIM3_Handle.Instance = TIM3;
	TIM3_Handle.Init.Period = (USBD_CDC_POLLING_INTERVAL*1000) - 1; // TIM3 fires every USBD_CDC_POLLING_INTERVAL ms
	TIM3_Handle.Init.Prescaler = 84-1; // for System clock at 168MHz, TIM3 runs at 1MHz
	TIM3_Handle.Init.ClockDivision = 0;
	TIM3_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
	HAL_TIM_Base_Init(&TIM3_Handle);

	HAL_NVIC_SetPriority(TIM3_IRQn, 6, 0);
	HAL_NVIC_EnableIRQ(TIM3_IRQn);

	if (HAL_TIM_Base_Start(&TIM3_Handle) != HAL_OK) {
	/* Starting Error */
	}
	}

	/* unused
	void timer_tim3_deinit(void) {
	// reset TIM3 timer
	__TIM3_FORCE_RESET();
	__TIM3_RELEASE_RESET();
	}
	*/

	// TIM5 is set-up for the servo controller
	// This function inits but does not start the timer
	void timer_tim5_init(void) {
	// TIM5 clock enable
	__TIM5_CLK_ENABLE();

	// set up and enable interrupt
	HAL_NVIC_SetPriority(TIM5_IRQn, 6, 0);
	HAL_NVIC_EnableIRQ(TIM5_IRQn);

	// PWM clock configuration
	TIM5_Handle.Instance = TIM5;
	TIM5_Handle.Init.Period = 2000; // timer cycles at 50Hz
	TIM5_Handle.Init.Prescaler = ((SystemCoreClock / 2) / 100000) - 1; // timer runs at 100kHz
	TIM5_Handle.Init.ClockDivision = 0;
	TIM5_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
	HAL_TIM_PWM_Init(&TIM5_Handle);
	}

	// Init TIM6 with a counter-overflow at the given frequency (given in Hz)
	// TIM6 is used by the DAC and ADC for auto sampling at a given frequency
	// This function inits but does not start the timer
	void timer_tim6_init(uint freq) {
	// TIM6 clock enable
	__TIM6_CLK_ENABLE();

	// Timer runs at SystemCoreClock / 2
	// Compute the prescaler value so TIM6 triggers at freq-Hz
	uint32_t period = MAX(1, (SystemCoreClock / 2) / freq);
	uint32_t prescaler = 1;
	while (period > 0xffff) {
	period >>= 1;
	prescaler <<= 1;
	}

	// Time base clock configuration
	TIM6_Handle.Instance = TIM6;
	TIM6_Handle.Init.Period = period - 1;
	TIM6_Handle.Init.Prescaler = prescaler - 1;
	TIM6_Handle.Init.ClockDivision = 0; // unused for TIM6
	TIM6_Handle.Init.CounterMode = TIM_COUNTERMODE_UP; // unused for TIM6
	HAL_TIM_Base_Init(&TIM6_Handle);
	}

	// Interrupt dispatch
	void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
	if (htim == &TIM3_Handle) {
	USBD_CDC_HAL_TIM_PeriodElapsedCallback();

	// Periodically raise a flash IRQ for the flash storage controller
	if (tim3_counter++ >= 500 / USBD_CDC_POLLING_INTERVAL) {
	tim3_counter = 0;
	NVIC->STIR = FLASH_IRQn;
	}

	} else if (htim == &TIM5_Handle) {
	servo_timer_irq_callback();
	}
	}

	/******************************************************************************/
	/* Micro Python bindings */

	STATIC void pyb_timer_print(void (print)(void env, const char fmt, ...), void env, mp_obj_t self_in, mp_print_kind_t kind) {
	pyb_timer_obj_t *self = self_in;

	if (self->tim.State == HAL_TIM_STATE_RESET) {
	print(env, "Timer(%u)", self->tim_id);
	} else {
	print(env, "Timer(%u, prescaler=%u, period=%u, mode=%u, div=%u)",
	self->tim_id,
	self->tim.Init.Prescaler,
	self->tim.Init.Period,
	self->tim.Init.CounterMode,
	self->tim.Init.ClockDivision
	);
	}
	}

	/// \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=100, period=300) # set the prescaler and period directly
	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 = TIM_COUNTERMODE_UP} },
	{ MP_QSTR_div, MP_ARG_KW_ONLY \| MP_ARG_INT, {.u_int = TIM_CLOCKDIVISION_DIV1} },
	};
	#define PYB_TIMER_INIT_NUM_ARGS 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);

	// set the TIM configuration values
	TIM_Base_InitTypeDef *init = &self->tim.Init;

	if (vals[0].u_int != 0xffffffff) {
	// set prescaler and period from frequency

	if (vals[0].u_int == 0) {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "can't have 0 frequency"));
	}

	// work out TIM's clock source
	uint tim_clock;
	if (self->tim_id == 1 \|\| (8 <= self->tim_id && self->tim_id <= 11)) {
	// TIM{1,8,9,10,11} are on APB2
	tim_clock = HAL_RCC_GetPCLK2Freq();
	} else {
	// TIM{2,3,4,5,6,7,12,13,14} are on APB1
	tim_clock = HAL_RCC_GetPCLK1Freq();
	}

	// compute the prescaler value so TIM triggers at freq-Hz
	// dpgeorge: I don't understand why we need to multiply tim_clock by 2
	uint32_t period = MAX(1, 2 * tim_clock / vals[0].u_int);
	uint32_t prescaler = 1;
	while (period > 0xffff) {
	period >>= 1;
	prescaler <<= 1;
	}
	init->Prescaler = prescaler - 1;
	init->Period = period - 1;
	} else if (vals[1].u_int != 0xffffffff && vals[2].u_int != 0xffffffff) {
	// set prescaler and period directly
	init->Prescaler = vals[1].u_int;
	init->Period = vals[2].u_int;
	} else {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "must specify either freq, or prescaler and period"));
	}

	init->CounterMode = vals[3].u_int;
	init->ClockDivision = vals[4].u_int;
	init->RepetitionCounter = 0;

	// init the TIM peripheral
	switch (self->tim_id) {
	case 1: __TIM1_CLK_ENABLE(); break;
	case 2: __TIM2_CLK_ENABLE(); break;
	case 3: __TIM3_CLK_ENABLE(); break;
	case 4: __TIM4_CLK_ENABLE(); break;
	case 5: __TIM5_CLK_ENABLE(); break;
	case 6: __TIM6_CLK_ENABLE(); break;
	case 7: __TIM7_CLK_ENABLE(); break;
	case 8: __TIM8_CLK_ENABLE(); break;
	case 9: __TIM9_CLK_ENABLE(); break;
	case 10: __TIM10_CLK_ENABLE(); break;
	case 11: __TIM11_CLK_ENABLE(); break;
	case 12: __TIM12_CLK_ENABLE(); break;
	case 13: __TIM13_CLK_ENABLE(); break;
	case 14: __TIM14_CLK_ENABLE(); break;
	}
	HAL_TIM_Base_Init(&self->tim);
	HAL_TIM_Base_Start(&self->tim);

	// set the priority (if not a special timer)
	if (self->tim_id != 3 && self->tim_id != 5) {
	HAL_NVIC_SetPriority(self->irqn, 0xe, 0xe); // next-to lowest priority
	}

	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(mp_obj_t type_in, uint n_args, uint 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);
	tim->base.type = &pyb_timer_type;
	tim->callback = mp_const_none;
	memset(&tim->tim, 0, sizeof(tim->tim));

	// get TIM number
	tim->tim_id = mp_obj_get_int(args[0]);

	switch (tim->tim_id) {
	case 1: tim->tim.Instance = TIM1; tim->irqn = TIM1_UP_TIM10_IRQn; break;
	case 2: tim->tim.Instance = TIM2; tim->irqn = TIM2_IRQn; break;
	case 3: nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "Timer 3 is for internal use only")); // TIM3 used for low-level stuff; go via regs if necessary
	case 4: tim->tim.Instance = TIM4; tim->irqn = TIM4_IRQn; break;
	case 5: tim->tim.Instance = TIM5; tim->irqn = TIM5_IRQn; break;
	case 6: tim->tim.Instance = TIM6; tim->irqn = TIM6_DAC_IRQn; break;
	case 7: tim->tim.Instance = TIM7; tim->irqn = TIM7_IRQn; break;
	case 8: tim->tim.Instance = TIM8; tim->irqn = TIM8_UP_TIM13_IRQn; break;
	case 9: tim->tim.Instance = TIM9; tim->irqn = TIM1_BRK_TIM9_IRQn; break;
	case 10: tim->tim.Instance = TIM10; tim->irqn = TIM1_UP_TIM10_IRQn; break;
	case 11: tim->tim.Instance = TIM11; tim->irqn = TIM1_TRG_COM_TIM11_IRQn; break;
	case 12: tim->tim.Instance = TIM12; tim->irqn = TIM8_BRK_TIM12_IRQn; break;
	case 13: tim->tim.Instance = TIM13; tim->irqn = TIM8_UP_TIM13_IRQn; break;
	case 14: tim->tim.Instance = TIM14; tim->irqn = TIM8_TRG_COM_TIM14_IRQn; 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 - 1 < PYB_TIMER_OBJ_ALL_NUM) {
	pyb_timer_obj_all[tim->tim_id - 1] = tim;
	}

	return (mp_obj_t)tim;
	}

	STATIC mp_obj_t pyb_timer_init(uint 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.
	///
	/// This function is not yet implemented.
	STATIC mp_obj_t pyb_timer_deinit(mp_obj_t self_in) {
	//pyb_timer_obj_t *self = self_in;
	// TODO implement me
	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_timer_deinit_obj, pyb_timer_deinit);

	/// \method counter([value])
	/// Get or set the timer counter.
	mp_obj_t pyb_timer_counter(uint 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->tim.Instance->CNT);
	} else {
	// set
	__HAL_TIM_SetCounter(&self->tim, mp_obj_get_int(args[1]));
	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.
	mp_obj_t pyb_timer_prescaler(uint 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->tim.Instance->PSC & 0xffff);
	} else {
	// set
	self->tim.Init.Prescaler = self->tim.Instance->PSC = mp_obj_get_int(args[1]) & 0xffff;
	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.
	mp_obj_t pyb_timer_period(uint 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->tim.Instance->ARR & 0xffff);
	} else {
	// set
	__HAL_TIM_SetAutoreload(&self->tim, mp_obj_get_int(args[1]) & 0xffff);
	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_TIM_DISABLE_IT(&self->tim, TIM_IT_UPDATE);
	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_TIM_Base_Start_IT(&self->tim);
	} else {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_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);

	STATIC const mp_map_elem_t pyb_timer_locals_dict_table[] = {
	// instance methods
	{ MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&pyb_timer_init_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_timer_deinit_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_counter), (mp_obj_t)&pyb_timer_counter_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_prescaler), (mp_obj_t)&pyb_timer_prescaler_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_period), (mp_obj_t)&pyb_timer_period_obj },
	{ MP_OBJ_NEW_QSTR(MP_QSTR_callback), (mp_obj_t)&pyb_timer_callback_obj },
	};

	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,
	};

	void timer_irq_handler(uint tim_id) {
	if (tim_id - 1 < PYB_TIMER_OBJ_ALL_NUM) {
	// get the timer object
	pyb_timer_obj_t *tim = pyb_timer_obj_all[tim_id - 1];

	if (tim == NULL) {
	// timer object has not been set, so we can't do anything
	return;
	}

	// see if it was a TIM update event (the only event we currently interrupt on)
	if (__HAL_TIM_GET_FLAG(&tim->tim, TIM_FLAG_UPDATE) != RESET) {
	if (__HAL_TIM_GET_ITSTATUS(&tim->tim, TIM_IT_UPDATE) != RESET) {
	// clear the interrupt
	__HAL_TIM_CLEAR_IT(&tim->tim, TIM_IT_UPDATE);

	// execute callback if it's set
	if (tim->callback != mp_const_none) {
	// 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(tim->callback, tim);
	nlr_pop();
	} else {
	// Uncaught exception; disable the callback so it doesn't run again.
	tim->callback = mp_const_none;
	__HAL_TIM_DISABLE_IT(&tim->tim, TIM_IT_UPDATE);
	printf("Uncaught exception in Timer(" UINT_FMT ") interrupt handler\n", tim->tim_id);
	mp_obj_print_exception((mp_obj_t)nlr.ret_val);
	}
	gc_unlock();
	}
	}
	}
	}
	}