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stmhal, timer: Factor code to compute PWM percent; improve 32bit case.

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Also do the same for teensy timer code.
This commit is contained in:
Damien George
2014-09-25 15:44:10 +01:00
parent 3fafe730d3
commit e8ea0724da
2 changed files with 106 additions and 89 deletions
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90
teensy/timer.c
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@@ -128,6 +128,37 @@ mp_uint_t get_prescaler_shift(mp_int_t prescaler) {
STATIC const mp_obj_type_t pyb_timer_channel_type;
// 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 val) {
uint32_t cmp;
if (0) {
#if MICROPY_PY_BUILTINS_FLOAT
} else if (MP_OBJ_IS_TYPE(val, &mp_type_float)) {
cmp = mp_obj_get_float(val) / 100.0 * period;
#endif
} else {
// For integer arithmetic, if period is large and 100*period will
// overflow, then divide period before multiplying by cmp. Otherwise
// do it the other way round to retain precision.
// TODO we really need an mp_obj_get_uint_clamped function here so
// that we can get long-int values as large as 0xffffffff.
cmp = mp_obj_get_int(val);
if (period > (1 << 31) / 100) {
cmp = cmp * (period / 100);
} else {
cmp = (cmp * period) / 100;
}
}
if (cmp < 0) {
cmp = 0;
} else if (cmp > period) {
cmp = period;
}
return cmp;
}
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;
@@ -373,7 +404,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_timer_deinit_obj, pyb_timer_deinit);
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 = 0xffffffff} },
{ 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} },
@@ -468,30 +499,13 @@ STATIC mp_obj_t pyb_timer_channel(mp_uint_t n_args, const mp_obj_t *args, mp_map
case CHANNEL_MODE_PWM_INVERTED: {
FTM_OC_InitTypeDef oc_config;
oc_config.OCMode = channel_mode_info[chan->mode].oc_mode;
if (vals[2].u_int != 0xffffffff) {
// absolute pulse width value given
oc_config.Pulse = vals[2].u_int;
} else if (vals[3].u_obj != mp_const_none) {
if (vals[3].u_obj != mp_const_none) {
// pulse width ratio given
uint32_t period = (self->ftm.Instance->MOD & 0xffff) + 1;
uint32_t cmp;
#if MICROPY_PY_BUILTINS_FLOAT
if (MP_OBJ_IS_TYPE(vals[3].u_obj, &mp_type_float)) {
cmp = mp_obj_get_float(vals[3].u_obj) * period / 100.0;
} else
#endif
{
cmp = mp_obj_get_int(vals[3].u_obj) * period / 100;
}
if (cmp < 0) {
cmp = 0;
} else if (cmp > period) {
cmp = period;
}
oc_config.Pulse = cmp;
oc_config.Pulse = compute_pwm_value_from_percent(period, vals[3].u_obj);
} else {
// nothing given, default to pulse width of 0
oc_config.Pulse = 0;
// use absolute pulse width value (defaults to 0 if nothing given)
oc_config.Pulse = vals[2].u_int;
}
oc_config.OCPolarity = FTM_OCPOLARITY_HIGH;
@@ -748,10 +762,11 @@ STATIC mp_obj_t pyb_timer_channel_capture_compare(mp_uint_t n_args, const mp_obj
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 ratio associated with a channel. The value is
/// a floating-point number between 0.0 and 1.0, and is relative to the period
/// of the timer associated with this channel. For example, a ratio of 0.5
/// would be a 50% duty cycle.
/// 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(mp_uint_t n_args, const mp_obj_t *args) {
pyb_timer_channel_obj_t *self = args[0];
FTM_TypeDef *FTMx = self->timer->ftm.Instance;
@@ -759,27 +774,14 @@ STATIC mp_obj_t pyb_timer_channel_pulse_width_percent(mp_uint_t n_args, const mp
if (n_args == 1) {
// get
uint32_t cmp = FTMx->channel[self->channel].CV & 0xffff;
#if MICROPY_PY_BUILTINS_FLOAT
return mp_obj_new_float((float)cmp * 100.0 / (float)period);
#else
#if MICROPY_PY_BUILTINS_FLOAT
return mp_obj_new_float((float)cmp / (float)period * 100.0);
#else
return mp_obj_new_int(cmp * 100 / period);
#endif
#endif
} else {
// set
uint32_t cmp;
#if MICROPY_PY_BUILTINS_FLOAT
if (MP_OBJ_IS_TYPE(args[1], &mp_type_float)) {
cmp = mp_obj_get_float(args[1]) * period / 100.0;
} else
#endif
{
cmp = mp_obj_get_int(args[1]) * period / 100;
}
if (cmp < 0) {
cmp = 0;
} else if (cmp > period) {
cmp = period;
}
uint32_t cmp = compute_pwm_value_from_percent(period, args[1]);
FTMx->channel[self->channel].CV = cmp & 0xffff;
return mp_const_none;
}