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circuitpython/stmhal/timer.c

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#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();
}
}
}
}
}
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