Revert to original functionality when synthio is not supported.

Author: relic-se

shared-bindings/audiomixer/MixerVoice.c

@@ -13,7 +13,9 @@
 #include "py/objproperty.h"
 #include "py/runtime.h"
 #include "shared-bindings/util.h"
+#if CIRCUITPY_SYNTHIO
 #include "shared-module/synthio/block.h"
+#endif
 
 //| class MixerVoice:
 //|     """Voice objects used with Mixer
@@ -77,7 +79,9 @@ static mp_obj_t audiomixer_mixervoice_obj_stop(size_t n_args, const mp_obj_t *po
 MP_DEFINE_CONST_FUN_OBJ_KW(audiomixer_mixervoice_stop_obj, 1, audiomixer_mixervoice_obj_stop);
 
 //|     level: synthio.BlockInput
-//|     """The volume level of a voice, as a floating point number between 0 and 1."""
+//|     """The volume level of a voice, as a floating point number between 0 and 1. If your board
+//|     does not support synthio, this property will only accept a float value.
+//|     """
 static mp_obj_t audiomixer_mixervoice_obj_get_level(mp_obj_t self_in) {
     return common_hal_audiomixer_mixervoice_get_level(self_in);
 }

shared-module/audiomixer/Mixer.c

@@ -188,12 +188,18 @@ static void mix_down_one_voice(audiomixer_mixer_obj_t *self,
             }
         }
 
-        uint32_t n = MIN(MIN(voice->buffer_length, length), SYNTHIO_MAX_DUR * self->channel_count);
         uint32_t *src = voice->remaining_buffer;
 
+        #if CIRCUITPY_SYNTHIO
+        uint32_t n = MIN(MIN(voice->buffer_length, length), SYNTHIO_MAX_DUR * self->channel_count);
+
         // Get the current level from the BlockInput. These may change at run time so you need to do bounds checking if required.
         shared_bindings_synthio_lfo_tick(self->sample_rate);
         uint16_t level = (uint16_t)(synthio_block_slot_get_limited(&voice->level, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0)) * (1 << 15));
+        #else
+        uint32_t n = MIN(voice->buffer_length, length);
+        uint16_t level = voice->level;
+        #endif
 
         // First active voice gets copied over verbatim.
         if (!voices_active) {

shared-module/audiomixer/MixerVoice.c

@@ -23,11 +23,19 @@ void common_hal_audiomixer_mixervoice_set_parent(audiomixer_mixervoice_obj_t *se
 }
 
 mp_obj_t common_hal_audiomixer_mixervoice_get_level(audiomixer_mixervoice_obj_t *self) {
+    #if CIRCUITPY_SYNTHIO
     return self->level.obj;
+    #else
+    return mp_obj_new_float((mp_float_t)self->level / (1 << 15));
+    #endif
 }
 
 void common_hal_audiomixer_mixervoice_set_level(audiomixer_mixervoice_obj_t *self, mp_obj_t arg) {
+    #if CIRCUITPY_SYNTHIO
     synthio_block_assign_slot(arg, &self->level, MP_QSTR_level);
+    #else
+    self->level = (uint16_t)(mp_arg_validate_obj_float_range(arg, 0, 1, MP_QSTR_level) * (1 << 15));
+    #endif
 }
 
 bool common_hal_audiomixer_mixervoice_get_loop(audiomixer_mixervoice_obj_t *self) {

shared-module/audiomixer/MixerVoice.h

@@ -9,7 +9,9 @@
 
 #include "shared-module/audiomixer/__init__.h"
 #include "shared-module/audiomixer/Mixer.h"
+#if CIRCUITPY_SYNTHIO
 #include "shared-module/synthio/block.h"
+#endif
 
 typedef struct {
     mp_obj_base_t base;
@@ -19,5 +21,9 @@ typedef struct {
     bool more_data;
     uint32_t *remaining_buffer;
     uint32_t buffer_length;
+    #if CIRCUITPY_SYNTHIO
     synthio_block_slot_t level;
+    #else
+    uint16_t level;
+    #endif
 } audiomixer_mixervoice_obj_t;