diff --git a/ports/atmel-samd/audio_dma.c b/ports/atmel-samd/audio_dma.c
index 0fe71e6d5d..b18db9c67a 100644
--- a/ports/atmel-samd/audio_dma.c
+++ b/ports/atmel-samd/audio_dma.c
@@ -45,6 +45,14 @@ static volatile bool audio_dma_pending[AUDIO_DMA_CHANNEL_COUNT];
 
 static bool audio_dma_allocated[AUDIO_DMA_CHANNEL_COUNT];
 
+uint8_t find_sync_event_channel_raise() {
+    uint8_t event_channel = find_sync_event_channel();
+    if (event_channel >= EVSYS_SYNCH_NUM) {
+        mp_raise_RuntimeError(translate("All sync event channels in use"));
+    }
+    return event_channel;
+}
+
 uint8_t audio_dma_allocate_channel(void) {
     uint8_t channel;
     for (channel = 0; channel < AUDIO_DMA_CHANNEL_COUNT; channel++) {
@@ -230,11 +238,7 @@ audio_dma_result audio_dma_setup_playback(audio_dma_t *dma,
 
         // We're likely double buffering so set up the block interrupts.
         turn_on_event_system();
-        dma->event_channel = find_sync_event_channel();
-
-        if (dma->event_channel >= EVSYS_SYNCH_NUM) {
-            mp_raise_RuntimeError(translate("All sync event channels in use"));
-        }
+        dma->event_channel = find_sync_event_channel_raise();
         init_event_channel_interrupt(dma->event_channel, CORE_GCLK, EVSYS_ID_GEN_DMAC_CH_0 + dma_channel);
 
         // We keep the audio_dma_t for internal use and the sample as a root pointer because it
diff --git a/ports/atmel-samd/audio_dma.h b/ports/atmel-samd/audio_dma.h
index 5506cff628..d6c766efb8 100644
--- a/ports/atmel-samd/audio_dma.h
+++ b/ports/atmel-samd/audio_dma.h
@@ -97,4 +97,6 @@ bool audio_dma_get_paused(audio_dma_t *dma);
 
 void audio_dma_background(void);
 
+uint8_t find_sync_event_channel_raise(void);
+
 #endif  // MICROPY_INCLUDED_ATMEL_SAMD_AUDIO_DMA_H
diff --git a/ports/atmel-samd/common-hal/audiobusio/PDMIn.c b/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
index 8911aef2f1..cbb50bec83 100644
--- a/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
+++ b/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
@@ -368,10 +368,7 @@ static uint16_t filter_sample(uint32_t pdm_samples[4]) {
 uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t* self,
         uint16_t* output_buffer, uint32_t output_buffer_length) {
     uint8_t dma_channel = audio_dma_allocate_channel();
-    uint8_t event_channel = find_sync_event_channel();
-    if (event_channel >= EVSYS_SYNCH_NUM) {
-        mp_raise_RuntimeError(translate("All sync event channels in use"));
-    }
+    uint8_t event_channel = find_sync_event_channel_raise();
 
     // We allocate two buffers on the stack to use for double buffering.
     const uint8_t samples_per_buffer = SAMPLES_PER_BUFFER;