micropython · IhorNehrutsa · Sep 4, 2023
diff --git a/docs/esp32/quickref.rst b/docs/esp32/quickref.rst
@@ -141,7 +141,7 @@ These are working configurations for LAN interfaces of popular boards::
     # Olimex ESP32-GATEWAY: power controlled by Pin(5)
     # Olimex ESP32 PoE and ESP32-PoE ISO: power controlled by Pin(12)
 
-    lan = network.LAN(mdc=machine.Pin(23), mdio=machine.Pin(18), power=machine.Pin(5), 
+    lan = network.LAN(mdc=machine.Pin(23), mdio=machine.Pin(18), power=machine.Pin(5),
                       phy_type=network.PHY_LAN8720, phy_addr=0,
                       ref_clk=machine.Pin(17), ref_clk_mode=machine.Pin.OUT)
 
@@ -330,6 +330,19 @@ possible at the same frequency.
 
 See more examples in the :ref:`esp32_pwm` tutorial.
 
+DAC (digital to analog conversion)
+----------------------------------
+
+On the ESP32, DAC functionality is available on pins 25, 26.
+On the ESP32S2, DAC functionality is available on pins 17, 18.
+
+Use the DAC::
+
+    from machine import DAC, Pin
+
+    dac = DAC(Pin(25))  # create an DAC object acting on a pin
+    dac.write(128)      # set a raw analog value in the range 0-255, 50% now
+
 ADC (analog to digital conversion)
 ----------------------------------
 

diff --git a/ports/esp32/machine_dac.c b/ports/esp32/machine_dac.c
@@ -87,7 +87,7 @@ STATIC mp_obj_t mdac_write(mp_obj_t self_in, mp_obj_t value_in) {
     mdac_obj_t *self = self_in;
     int value = mp_obj_get_int(value_in);
     if (value < 0 || value > 255) {
-        mp_raise_ValueError(MP_ERROR_TEXT("value out of range"));
+        mp_raise_ValueError(MP_ERROR_TEXT("value out of range [0..255]"));
     }
 
     esp_err_t err = dac_output_voltage(self->dac_id, value);
@@ -98,8 +98,24 @@ STATIC mp_obj_t mdac_write(mp_obj_t self_in, mp_obj_t value_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_2(mdac_write_obj, mdac_write);
 
+STATIC mp_obj_t mdac_deinit(mp_obj_t self_in) {
+    mdac_obj_t *self = self_in;
+    check_esp_err(dac_output_disable(self->dac_id));
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mdac_deinit_obj, mdac_deinit);
+
+// This called from Ctrl-D soft reboot
+void machine_dac_deinit_all(void) {
+    for (int i = 0; i < MP_ARRAY_SIZE(mdac_obj); i++) {
+        mdac_deinit((mdac_obj_t *)&mdac_obj[i]);
+    }
+}
+
 STATIC const mp_rom_map_elem_t mdac_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mdac_write_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&mdac_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&mdac_deinit_obj) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(mdac_locals_dict, mdac_locals_dict_table);

diff --git a/ports/esp32/main.c b/ports/esp32/main.c
@@ -182,6 +182,9 @@ void mp_task(void *pvParameter) {
 
     // deinitialise peripherals
     machine_pwm_deinit_all();
+    #if MICROPY_PY_MACHINE_DAC
+    machine_dac_deinit_all();
+    #endif
     // TODO: machine_rmt_deinit_all();
     machine_pins_deinit();
     machine_deinit();

diff --git a/ports/esp32/modmachine.h b/ports/esp32/modmachine.h
@@ -18,6 +18,9 @@ void machine_deinit(void);
 void machine_pins_init(void);
 void machine_pins_deinit(void);
 void machine_pwm_deinit_all(void);
+#if MICROPY_PY_MACHINE_DAC
+void machine_dac_deinit_all(void);
+#endif
 // TODO: void machine_rmt_deinit_all(void);
 void machine_timer_deinit_all(void);
 void machine_i2s_init0();