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stmhal, timer: Set freq from float; get timer source freq.

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Timers now have the following new features:
- can init freq using floating point; eg tim.init(freq=0.1)
- tim.source_freq() added to get freq of timer clock source
- tim.freq() added to get/set freq
- print(tim) now prints freq
This commit is contained in:
Damien George 2014-10-04 14:36:39 +01:00
parent c3ab90da46
commit 97ef94df83
2 changed files with 136 additions and 65 deletions
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1
stmhal/qstrdefsport.h
View File

@ -166,6 +166,7 @@ Q(init)
Q(deinit)
Q(channel)
Q(counter)
Q(source_freq)
Q(prescaler)
Q(period)
Q(callback)

188
stmhal/timer.c
View File

@ -133,7 +133,6 @@ typedef struct _pyb_timer_obj_t {
TIM_HandleTypeDef tim;
IRQn_Type irqn;
pyb_timer_channel_obj_t *channel;
} pyb_timer_obj_t;
// The following yields TIM_IT_UPDATE when channel is zero and
@ -153,6 +152,7 @@ STATIC uint32_t tim3_counter = 0;
STATIC pyb_timer_obj_t *pyb_timer_obj_all[14];
#define PYB_TIMER_OBJ_ALL_NUM MP_ARRAY_SIZE(pyb_timer_obj_all)
STATIC uint32_t timer_get_source_freq(uint32_t tim_id);
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);
@ -181,7 +181,7 @@ void timer_tim3_init(void) {
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 = 2 * HAL_RCC_GetPCLK1Freq() / 1000000 - 1; // TIM3 runs at 1MHz
TIM3_Handle.Init.Prescaler = timer_get_source_freq(3) / 1000000 - 1; // TIM3 runs at 1MHz
TIM3_Handle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
TIM3_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
HAL_TIM_Base_Init(&TIM3_Handle);
@ -215,7 +215,7 @@ void timer_tim5_init(void) {
// PWM clock configuration
TIM5_Handle.Instance = TIM5;
TIM5_Handle.Init.Period = 2000 - 1; // timer cycles at 50Hz
TIM5_Handle.Init.Prescaler = ((SystemCoreClock / 2) / 100000) - 1; // timer runs at 100kHz
TIM5_Handle.Init.Prescaler = (timer_get_source_freq(5) / 100000) - 1; // timer runs at 100kHz
TIM5_Handle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
TIM5_Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
@ -231,7 +231,7 @@ void timer_tim6_init(uint freq) {
// 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 period = MAX(1, timer_get_source_freq(6) / freq);
uint32_t prescaler = 1;
while (period > 0xffff) {
period >>= 1;
@ -263,6 +263,29 @@ void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
}
}
// Get the frequency (in Hz) of the source clock for the given timer.
// On STM32F405/407/415/417 there are 2 cases for how the clock freq is set.
// If the APB prescaler is 1, then the timer clock is equal to its respective
// APB clock. Otherwise (APB prescaler > 1) the timer clock is twice its
// respective APB clock. See DM00031020 Rev 4, page 115.
STATIC uint32_t timer_get_source_freq(uint32_t tim_id) {
uint32_t source;
if (tim_id == 1 || (8 <= tim_id && tim_id <= 11)) {
// TIM{1,8,9,10,11} are on APB2
source = HAL_RCC_GetPCLK2Freq();
if ((uint32_t)((RCC->CFGR & RCC_CFGR_PPRE2) >> 3) != RCC_HCLK_DIV1) {
source *= 2;
}
} else {
// TIM{2,3,4,5,6,7,12,13,14} are on APB1
source = HAL_RCC_GetPCLK1Freq();
if ((uint32_t)(RCC->CFGR & RCC_CFGR_PPRE1) != RCC_HCLK_DIV1) {
source *= 2;
}
}
return source;
}
/******************************************************************************/
/* Micro Python bindings */
@ -272,6 +295,37 @@ STATIC const mp_obj_type_t pyb_timer_channel_type;
// fit in a uint32_t.
#define MAX_PERIOD_DIV_100 42949672
// computes prescaler and period so TIM triggers at freq-Hz
STATIC uint32_t compute_prescaler_period_from_freq(pyb_timer_obj_t *self, mp_obj_t freq_in, uint32_t *period_out) {
uint32_t source_freq = timer_get_source_freq(self->tim_id);
uint32_t prescaler = 1;
uint32_t period;
if (0) {
#if MICROPY_PY_BUILTINS_FLOAT
} else if (MP_OBJ_IS_TYPE(freq_in, &mp_type_float)) {
float freq = mp_obj_get_float(freq_in);
if (freq <= 0) {
goto bad_freq;
}
period = MAX(1, source_freq / freq);
#endif
} else {
mp_int_t freq = mp_obj_get_int(freq_in);
if (freq <= 0) {
goto bad_freq;
bad_freq:
nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "must have positive freq"));
}
period = MAX(1, source_freq / freq);
}
while (period > TIMER_CNT_MASK(self)) {
prescaler <<= 1;
period >>= 1;
}
*period_out = (period - 1) & TIMER_CNT_MASK(self);
return (prescaler - 1) & 0xffff;
}
// 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%
@ -351,10 +405,15 @@ STATIC void pyb_timer_print(void (*print)(void *env, const char *fmt, ...), void
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=%s, div=%u)",
uint32_t prescaler = self->tim.Instance->PSC & 0xffff;
uint32_t period = __HAL_TIM_GetAutoreload(&self->tim) & TIMER_CNT_MASK(self);
// for efficiency, we compute and print freq as an int (not a float)
uint32_t freq = timer_get_source_freq(self->tim_id) / ((prescaler + 1) * (period + 1));
print(env, "Timer(%u, freq=%u, prescaler=%u, period=%u, mode=%s, div=%u)",
self->tim_id,
self->tim.Instance->PSC & 0xffff,
__HAL_TIM_GetAutoreload(&self->tim) & TIMER_CNT_MASK(self),
freq,
prescaler,
period,
self->tim.Init.CounterMode == TIM_COUNTERMODE_UP ? "UP" :
self->tim.Init.CounterMode == TIM_COUNTERMODE_DOWN ? "DOWN" : "CENTER",
self->tim.Init.ClockDivision == TIM_CLOCKDIVISION_DIV4 ? 4 :
@ -399,74 +458,46 @@ STATIC void pyb_timer_print(void (*print)(void *env, const char *fmt, ...), void
/// - `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} },
STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
{ 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 = 1} },
{ 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, mp_uint_t 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);
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// 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
// On STM32F405/407/415/417 there are 2 cases for how the clock freq is set.
// If the APB prescaler is 1, then the timer clock is equal to its respective
// APB clock. Otherwise (APB prescaler > 1) the timer clock is twice its
// respective APB clock. See DM00031020 Rev 4, page 115.
uint32_t period = MAX(1, 2 * tim_clock / vals[0].u_int);
uint32_t prescaler = 1;
while (period > TIMER_CNT_MASK(self)) {
period >>= 1;
prescaler <<= 1;
}
init->Prescaler = prescaler - 1;
init->Period = period - 1;
} else if (vals[1].u_int != 0xffffffff && vals[2].u_int != 0xffffffff) {
if (args[0].u_obj != mp_const_none) {
// set prescaler and period from desired frequency
init->Prescaler = compute_prescaler_period_from_freq(self, args[0].u_obj, &init->Period);
} else if (args[1].u_int != 0xffffffff && args[2].u_int != 0xffffffff) {
// set prescaler and period directly
init->Prescaler = vals[1].u_int;
init->Period = vals[2].u_int;
init->Prescaler = args[1].u_int;
init->Period = args[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 == 2 ? TIM_CLOCKDIVISION_DIV2 :
vals[4].u_int == 4 ? TIM_CLOCKDIVISION_DIV4 :
TIM_CLOCKDIVISION_DIV1;
init->RepetitionCounter = 0;
init->CounterMode = args[3].u_int;
if (!IS_TIM_COUNTER_MODE(init->CounterMode)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Invalid counter_mode (%d)", init->CounterMode));
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "invalid mode (%d)", init->CounterMode));
}
// init the TIM peripheral
init->ClockDivision = args[4].u_int == 2 ? TIM_CLOCKDIVISION_DIV2 :
args[4].u_int == 4 ? TIM_CLOCKDIVISION_DIV4 :
TIM_CLOCKDIVISION_DIV1;
init->RepetitionCounter = 0;
// enable TIM clock
switch (self->tim_id) {
case 1: __TIM1_CLK_ENABLE(); break;
case 2: __TIM2_CLK_ENABLE(); break;
@ -483,16 +514,18 @@ STATIC mp_obj_t pyb_timer_init_helper(pyb_timer_obj_t *self, mp_uint_t n_args, c
case 13: __TIM13_CLK_ENABLE(); break;
case 14: __TIM14_CLK_ENABLE(); break;
}
// set the priority (if not a special timer)
// set IRQ 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
}
// init TIM
HAL_TIM_Base_Init(&self->tim);
if (vals[5].u_obj == mp_const_none) {
if (args[5].u_obj == mp_const_none) {
HAL_TIM_Base_Start(&self->tim);
} else {
pyb_timer_callback(self, vals[5].u_obj);
pyb_timer_callback(self, args[5].u_obj);
}
return mp_const_none;
@ -839,6 +872,41 @@ STATIC mp_obj_t pyb_timer_counter(mp_uint_t n_args, const mp_obj_t *args) {
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_counter_obj, 1, 2, pyb_timer_counter);
/// \method source_freq()
/// Get the frequency of the source of the timer.
STATIC mp_obj_t pyb_timer_source_freq(mp_obj_t self_in) {
pyb_timer_obj_t *self = self_in;
uint32_t source_freq = timer_get_source_freq(self->tim_id);
return mp_obj_new_int(source_freq);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_timer_source_freq_obj, pyb_timer_source_freq);
/// \method freq([value])
/// Get or set the frequency for the timer (changes prescaler and period if set).
STATIC mp_obj_t pyb_timer_freq(mp_uint_t n_args, const mp_obj_t *args) {
pyb_timer_obj_t *self = args[0];
if (n_args == 1) {
// get
uint32_t prescaler = self->tim.Instance->PSC & 0xffff;
uint32_t period = __HAL_TIM_GetAutoreload(&self->tim) & TIMER_CNT_MASK(self);
uint32_t source_freq = timer_get_source_freq(self->tim_id);
uint32_t divide = ((prescaler + 1) * (period + 1));
if (source_freq % divide == 0) {
return mp_obj_new_int(source_freq / divide);
} else {
return mp_obj_new_float((float)source_freq / (float)divide);
}
} else {
// set
uint32_t period;
uint32_t prescaler = compute_prescaler_period_from_freq(self, args[1], &period);
self->tim.Instance->PSC = prescaler;
__HAL_TIM_SetAutoreload(&self->tim, period);
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_timer_freq_obj, 1, 2, pyb_timer_freq);
/// \method prescaler([value])
/// Get or set the prescaler for the timer.
STATIC mp_obj_t pyb_timer_prescaler(mp_uint_t n_args, const mp_obj_t *args) {
@ -848,7 +916,7 @@ STATIC mp_obj_t pyb_timer_prescaler(mp_uint_t n_args, const mp_obj_t *args) {
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;
self->tim.Instance->PSC = mp_obj_get_int(args[1]) & 0xffff;
return mp_const_none;
}
}
@ -897,6 +965,8 @@ STATIC const mp_map_elem_t pyb_timer_locals_dict_table[] = {
{ MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_timer_deinit_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_channel), (mp_obj_t)&pyb_timer_channel_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_counter), (mp_obj_t)&pyb_timer_counter_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_source_freq), (mp_obj_t)&pyb_timer_source_freq_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_freq), (mp_obj_t)&pyb_timer_freq_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 },