stmhal, timer: Set freq from float; get timer source freq.
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
diff --git a/stmhal/timer.c b/stmhal/timer.c
index 5efecbc..3465003 100644
--- a/stmhal/timer.c
+++ b/stmhal/timer.c
@@ -133,7 +133,6 @@
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 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 @@
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 @@
// 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 @@
// 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 @@
}
}
+// 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 @@
// 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 @@
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 @@
/// - `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 = 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 *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} },
+ };
-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 @@
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_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 @@
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 @@
{ 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 },