8000 rp2/PWM: Support inverting a channel output. · micropython/micropython@9eea19b · GitHub
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rp2/PWM: Support inverting a channel output.
Using the invert=True|False keyword option with the constructor or init().
1 parent bf4c540 commit 9eea19b

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3 files changed

+55
-37
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3 files changed

+55
-37
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‎docs/library/machine.PWM.rst

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,7 @@ Example usage::
2424
Constructors
2525
------------
2626

27-
.. class:: PWM(dest, *, freq, duty_u16, duty_ns)
27+
.. class:: PWM(dest, *, freq, duty_u16, duty_ns, invert)
2828

2929
Construct and return a new PWM object using the following parameters:
3030

@@ -35,10 +35,12 @@ Constructors
3535
PWM cycle.
3636
- *duty_u16* sets the duty cycle as a ratio ``duty_u16 / 65535``.
3737
- *duty_ns* sets the pulse width in nanoseconds.
38+
- *invert* inverts the respective output if the value is True
3839

3940
Setting *freq* may affect other PWM objects if the objects share the same
4041
underlying PWM generator (this is hardware specific).
4142
Only one of *duty_u16* and *duty_ns* should be specified at a time.
43+
*invert* is not available at all ports.
4244

4345
Methods
4446
-------

‎docs/samd/quickref.rst

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -192,7 +192,7 @@ It supports all basic methods listed for that class. ::
192192
PWM Constructor
193193
```````````````
194194

195-
.. class:: PWM(dest, freq, duty_u16, duty_ns, *, invert, device)
195+
.. class:: PWM(dest, *, freq, duty_u16, duty_ns, invert, device)
196196
:noindex:
197197

198198
Construct and return a new PWM object using the following parameters:

‎ports/rp2/machine_pwm.c

Lines changed: 51 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -38,8 +38,8 @@ typedef struct _machine_pwm_obj_t {
3838
mp_obj_base_t base;
3939
uint8_t slice;
4040
uint8_t channel;
41+
uint8_t invert;
4142
uint8_t duty_type;
42-
bool freq_set;
4343
mp_int_t duty;
4444
} machine_pwm_obj_t;
4545

@@ -51,67 +51,80 @@ enum {
5151
};
5252

5353
STATIC machine_pwm_obj_t machine_pwm_obj[] = {
54-
{{&machine_pwm_type}, 0, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
55-
{{&machine_pwm_type}, 0, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
56-
{{&machine_pwm_type}, 1, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
57-
{{&machine_pwm_type}, 1, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
58-
{{&machine_pwm_type}, 2, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
59-
{{&machine_pwm_type}, 2, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
60-
{{&machine_pwm_type}, 3, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
61-
{{&machine_pwm_type}, 3, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
62-
{{&machine_pwm_type}, 4, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
63-
{{&machine_pwm_type}, 4, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
64-
{{&machine_pwm_type}, 5, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
65-
{{&machine_pwm_type}, 5, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
66-
{{&machine_pwm_type}, 6, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
67-
{{&machine_pwm_type}, 6, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
68-
{{&machine_pwm_type}, 7, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
69-
{{&machine_pwm_type}, 7, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
54+
{{&machine_pwm_type}, 0, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
55+
{{&machine_pwm_type}, 0, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
56+
{{&machine_pwm_type}, 1, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
57+
{{&machine_pwm_type}, 1, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
58+
{{&machine_pwm_type}, 2, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
59+
{{&machine_pwm_type}, 2, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
60+
{{&machine_pwm_type}, 3, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
61+
{{&machine_pwm_type}, 3, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
62+
{{&machine_pwm_type}, 4, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
63+
{{&machine_pwm_type}, 4, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
64+
{{&machine_pwm_type}, 5, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
65+
{{&machine_pwm_type}, 5, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
66+
{{&machine_pwm_type}, 6, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
67+
{{&machine_pwm_type}, 6, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
68+
{{&machine_pwm_type}, 7, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
69+
{{&machine_pwm_type}, 7, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
7070
};
7171

72+
STATIC bool defer_start;
73+
STATIC bool slice_freq_set[8];
74+
7275
STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq);
7376
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16);
7477
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns);
7578

7679
STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
7780
machine_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
78-
mp_printf(print, "<PWM slice=%u channel=%u>", self->slice, self->channel);
81+
mp_printf(print, "<PWM slice=%u channel=%u invert=%u>",
82+
self->slice, self->channel, self->invert);
7983
}
8084

8185
void machine_pwm_start(machine_pwm_obj_t *self) {
8286
// Start the PWM if properly set.
83-
if (self->freq_set && self->duty_type != DUTY_NOT_SET) {
87+
if (defer_start == false && slice_freq_set[self->slice] == true && self->duty_type != DUTY_NOT_SET) {
88+
if (self->channel == PWM_CHAN_A) {
89+
pwm_set_output_polarity(self->slice, self->invert, (self + 1)->invert);
90+
} else {
91+
pwm_set_output_polarity(self->slice, (self - 1)->invert, self->invert);
92+
}
8493
pwm_set_enabled(self->slice, true);
8594
}
8695
}
8796

8897
STATIC void mp_machine_pwm_init_helper(machine_pwm_obj_t *self,
8998
size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
90-
enum { ARG_freq, ARG_duty_u16, ARG_duty_ns };
99+
enum { ARG_freq, ARG_duty_u16, ARG_duty_ns, ARG_invert };
91100
static const mp_arg_t allowed_args[] = {
92101
{ MP_QSTR_freq, MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
93102
{ MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
94103
{ MP_QSTR_duty_ns, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
104+
{ MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
95105
};
96106

97107
// Parse the arguments.
98108
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
99109
mp_arg_parse_all(n_args, pos_args, kw_args,
100110
MP_ARRAY_SIZE(allowed_args), allowed_args, args);
101111

102-
if ((n_args + kw_args->used) > 0) {
103-
if (args[ARG_freq].u_int != VALUE_NOT_SET) {
104-
mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
105-
}
106-
if (args[ARG_duty_u16].u_int != VALUE_NOT_SET) {
107-
mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
108-
}
109-
if (args[ARG_duty_ns].u_int != VALUE_NOT_SET) {
110-
mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
111-
}
112-
} else {
113-
machine_pwm_start(self);
112+
// defer starting PWM until all provided args are checked.
113+
defer_start = true;
114+
if (args[ARG_freq].u_int != VALUE_NOT_SET) {
115+
mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
116+
}
117+
if (args[ARG_duty_u16].u_int != VALUE_NOT_SET) {
118+
mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
119+
}
120+
if (args[ARG_duty_ns].u_int != VALUE_NOT_SET) {
121+
mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
114122
}
123+
if (args[ARG_invert].u_int != VALUE_NOT_SET) {
124+
self->invert = !!args[ARG_invert].u_int;
125+
}
126+
defer_start = false;
127+
machine_pwm_start(self);
115128
}
116129

117130
// PWM(pin [, args])
@@ -126,7 +139,7 @@ STATIC mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args
126139
uint slice = pwm_gpio_to_slice_num(gpio);
127140
uint8_t channel = pwm_gpio_to_channel(gpio);
128141
machine_pwm_obj_t *self = &machine_pwm_obj[slice * 2 + channel];
129-
self->freq_set = false;
142+
self->invert = 0;
130143
self->duty_type = DUTY_NOT_SET;
131144

132145
// Select PWM function for given GPIO.
@@ -143,6 +156,7 @@ STATIC mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args
143156
// Stop all active slices.
144157
void machine_pwm_deinit_all(void) {
145158
for (int i = 0; i < 8; i++) {
159+
slice_freq_set[i] = false;
146160
pwm_set_enabled(machine_pwm_obj[i].slice, false);
147161
}
148162
}
@@ -216,14 +230,16 @@ STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
216230
}
217231
pwm_hw->slice[self->slice].div = div16;
218232
pwm_hw->slice[self->slice].top = top;
219-
self->freq_set = true;
233+
slice_freq_set[self->slice] = true;
220234
if (self->duty_type == DUTY_U16) {
221235
mp_machine_pwm_duty_set_u16(self, self->duty);
222236
} else if (self->duty_type == DUTY_NS) {
223237
mp_machine_pwm_duty_set_ns(self, self->duty);
224238
}
225239
machine_pwm_obj_t *other = self->channel == PWM_CHAN_A ? self + 1 : self - 1;
226-
if (other->duty_type == DUTY_NS) {
240+
if (other->duty_type == DUTY_U16) {
241+
mp_machine_pwm_duty_set_u16(other, other->duty);
242+
} else if (other->duty_type == DUTY_NS) {
227243
mp_machine_pwm_duty_set_ns(other, other->duty);
228244
}
229245
}

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