diff --git a/ports/atmel-samd/common-hal/pulseio/PulseIn.c b/ports/atmel-samd/common-hal/pulseio/PulseIn.c
index 7ea20321b2..b825579dbe 100644
--- a/ports/atmel-samd/common-hal/pulseio/PulseIn.c
+++ b/ports/atmel-samd/common-hal/pulseio/PulseIn.c
@@ -125,6 +125,9 @@ void pulsein_interrupt_handler(uint8_t channel) {
 }
 
 void pulsein_reset() {
+#ifdef SAMD21
+    rtc_end_pulsein();
+#endif
     refcount = 0;
     pulsein_tc_index = 0xff;
     overflow_count = 0;
@@ -221,6 +224,10 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self,
 
     // Set config will enable the EIC.
     pulsein_set_config(self, true);
+#ifdef SAMD21
+    rtc_start_pulsein();
+#endif
+
 }
 
 bool common_hal_pulseio_pulsein_deinited(pulseio_pulsein_obj_t* self) {
@@ -231,6 +238,9 @@ void common_hal_pulseio_pulsein_deinit(pulseio_pulsein_obj_t* self) {
     if (common_hal_pulseio_pulsein_deinited(self)) {
         return;
     }
+#ifdef SAMD21
+    rtc_end_pulsein();
+#endif
     set_eic_handler(self->channel, EIC_HANDLER_NO_INTERRUPT);
     turn_off_eic_channel(self->channel);
     reset_pin_number(self->pin);
diff --git a/ports/atmel-samd/common-hal/pulseio/PulseIn.h b/ports/atmel-samd/common-hal/pulseio/PulseIn.h
index 89b61a83ac..99358178f2 100644
--- a/ports/atmel-samd/common-hal/pulseio/PulseIn.h
+++ b/ports/atmel-samd/common-hal/pulseio/PulseIn.h
@@ -50,5 +50,11 @@ void pulsein_reset(void);
 
 void pulsein_interrupt_handler(uint8_t channel);
 void pulsein_timer_interrupt_handler(uint8_t index);
+#ifdef SAMD21
+void rtc_set_continuous(void);
+void rtc_start_pulsein(void);
+void rtc_end_pulsein(void);
+#endif
+
 
 #endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_PULSEIO_PULSEIN_H
diff --git a/ports/atmel-samd/supervisor/port.c b/ports/atmel-samd/supervisor/port.c
index 48bd3211b5..e892e6cde5 100644
--- a/ports/atmel-samd/supervisor/port.c
+++ b/ports/atmel-samd/supervisor/port.c
@@ -91,6 +91,23 @@
 #if CIRCUITPY_PEW
 #include "common-hal/_pew/PewPew.h"
 #endif
+volatile bool hold_interrupt = false;
+#ifdef SAMD21
+void rtc_start_pulsein(void) {
+    rtc_set_continuous();
+    hold_interrupt = true;
+}
+
+void rtc_end_pulsein(void) {
+    hold_interrupt = false;
+}
+
+void rtc_set_continuous(void) {
+    while (RTC->MODE0.STATUS.bit.SYNCBUSY);
+    RTC->MODE0.READREQ.reg = RTC_READREQ_RREQ | RTC_READREQ_RCONT | 0x0010;
+    while (RTC->MODE0.STATUS.bit.SYNCBUSY);
+}
+#endif
 
 extern volatile bool mp_msc_enabled;
 
@@ -489,6 +506,11 @@ void port_interrupt_after_ticks(uint32_t ticks) {
         // We'll interrupt sooner with an overflow.
         return;
     }
+#ifdef SAMD21
+    if (hold_interrupt) {
+        return;
+    }
+#endif
     RTC->MODE0.COMP[0].reg = current_ticks + (ticks << 4);
     RTC->MODE0.INTFLAG.reg = RTC_MODE0_INTFLAG_CMP0;
     RTC->MODE0.INTENSET.reg = RTC_MODE0_INTENSET_CMP0;
@@ -503,7 +525,7 @@ void port_sleep_until_interrupt(void) {
     }
     #endif
     common_hal_mcu_disable_interrupts();
-    if (!tud_task_event_ready()) {
+    if (!tud_task_event_ready() && !hold_interrupt) {
         __DSB();
         __WFI();
     }