Initial pulseio.PulseOut implementation for #716 ESP8266

Author: nickzoic

ports/esp8266/common-hal/pulseio/PulseOut.c

@@ -24,23 +24,85 @@
  * THE SOFTWARE.
  */
 
+#include "common-hal/pulseio/PulseOut.h"
 
 #include <stdint.h>
 
+#include <pwm.h>
+
+#include "ets_alt_task.h"
+#include "py/obj.h"
 #include "py/runtime.h"
+#include "mpconfigport.h"
 #include "shared-bindings/pulseio/PulseOut.h"
 
+#define NO_CHANNEL (255)
+
+static uint16_t *pulse_buffer = NULL;
+static volatile uint16_t pulse_index = 0;
+static uint16_t pulse_length;
+static volatile uint32_t current_compare = 0;
+
+void pulseout_set(pulseio_pulseout_obj_t *self, bool state) {
+    // XXX double kludge
+    //uint32_t duty = state ? pwm_get_period() * 11 : 0;
+    uint32_t duty = state ? 1000 : 500;
+    pwm_set_duty(duty, self->channel);
+    pwm_start();
+}
+
+void pulseout_interrupt_handler(void *data) {
+    pulseio_pulseout_obj_t *self = data;
+
+    if (pulse_buffer == NULL || self->channel == NO_CHANNEL) return;
+    if (pulse_index >= pulse_length) return;
+    pulse_index++;
+    pulseout_set(self, pulse_index % 2 == 0);
+
+    os_timer_arm(&self->timer, pulse_buffer[pulse_index], 0);
+}
+
+void pulseout_reset() {
+    pulse_buffer = NULL;
+}
+
 void common_hal_pulseio_pulseout_construct(pulseio_pulseout_obj_t* self,
                                             const pulseio_pwmout_obj_t* carrier) {
-    nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "No hardware support for PulseOut."));
+    self->channel = carrier->channel;
 }
 
 bool common_hal_pulseio_pulseout_deinited(pulseio_pulseout_obj_t* self) {
-    return true;
+    return self->channel == NO_CHANNEL;
 }
 
 void common_hal_pulseio_pulseout_deinit(pulseio_pulseout_obj_t* self) {
+    os_timer_disarm(&self->timer);
+    self->channel = NO_CHANNEL;
+    pulseout_set(self, true);
 }
 
 void common_hal_pulseio_pulseout_send(pulseio_pulseout_obj_t* self, uint16_t* pulses, uint16_t length) {
+    if (pulse_buffer != NULL) {
+        mp_raise_RuntimeError("Another send is already active");
+    }
+    pulse_buffer = pulses;
+    pulse_index = 0;
+    pulse_length = length;
+
+    os_timer_disarm(&self->timer);
+    os_timer_setfn(&self->timer, pulseout_interrupt_handler, self);
+    os_timer_arm(&self->timer, pulse_buffer[0], 0);
+    pulseout_set(self, true);
+
+    // XXX in the circumstances, is it worth messing with os_timer?
+    // it isn't especially accurate anyway ...
+    // might it not be simpler to just call mp_hal_delay_us() a lot?
+    while(pulse_index < length) {
+        ets_loop_iter();
+    }
+
+    os_timer_disarm(&self->timer);
+    pulseout_set(self, false);
+
+    pulse_buffer = NULL;
 }

ports/esp8266/common-hal/pulseio/PulseOut.h

@@ -27,12 +27,19 @@
 #ifndef MICROPY_INCLUDED_ESP8266_COMMON_HAL_PULSEIO_PULSEOUT_H
 #define MICROPY_INCLUDED_ESP8266_COMMON_HAL_PULSEIO_PULSEOUT_H
 
+#include "common-hal/microcontroller/Pin.h"
+
+#include "esp_mphal.h"
+
 #include "py/obj.h"
 
 typedef struct {
     mp_obj_base_t base;
+    os_timer_t timer;
+    uint8_t channel;
 } pulseio_pulseout_obj_t;
 
-void pwmout_reset(void);
+void pulseout_reset(void);
+void pulseout_interrupt_handler(void *);
 
 #endif // MICROPY_INCLUDED_ESP8266_COMMON_HAL_PULSEIO_PULSEOUT_H