diff --git a/extmod/modmachine.c b/extmod/modmachine.c
index e0bef3a73f..311d5dc037 100644
--- a/extmod/modmachine.c
+++ b/extmod/modmachine.c
@@ -35,6 +35,10 @@
 #include "drivers/dht/dht.h"
 #endif
 
+// The port must provide implementations of these low-level machine functions.
+
+STATIC void mp_machine_idle(void);
+
 // The port can provide additional machine-module implementation in this file.
 #ifdef MICROPY_PY_MACHINE_INCLUDEFILE
 #include MICROPY_PY_MACHINE_INCLUDEFILE
@@ -46,6 +50,12 @@ STATIC mp_obj_t machine_soft_reset(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_soft_reset_obj, machine_soft_reset);
 
+STATIC mp_obj_t machine_idle(void) {
+    mp_machine_idle();
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
+
 STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_machine) },
 
@@ -57,6 +67,9 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     // Reset related functions.
     { MP_ROM_QSTR(MP_QSTR_soft_reset), MP_ROM_PTR(&machine_soft_reset_obj) },
 
+    // Power related functions.
+    { MP_ROM_QSTR(MP_QSTR_idle), MP_ROM_PTR(&machine_idle_obj) },
+
     // Functions for bit protocols.
     #if MICROPY_PY_MACHINE_BITSTREAM
     { MP_ROM_QSTR(MP_QSTR_bitstream), MP_ROM_PTR(&machine_bitstream_obj) },
diff --git a/ports/cc3200/mods/modmachine.c b/ports/cc3200/mods/modmachine.c
index 8673c62865..1df11c9d28 100644
--- a/ports/cc3200/mods/modmachine.c
+++ b/ports/cc3200/mods/modmachine.c
@@ -62,7 +62,6 @@
     { MP_ROM_QSTR(MP_QSTR_unique_id),           MP_ROM_PTR(&machine_unique_id_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_main),                MP_ROM_PTR(&machine_main_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_rng),                 MP_ROM_PTR(&machine_rng_get_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_sleep),               MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep),          MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),           MP_ROM_PTR(&machine_deepsleep_obj) }, \
@@ -168,11 +167,9 @@ STATIC mp_obj_t machine_main(mp_obj_t main) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(machine_main_obj, machine_main);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     __WFI();
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(void) {
     pyb_sleep_sleep();
diff --git a/ports/esp32/modmachine.c b/ports/esp32/modmachine.c
index a1bd9a5cb9..1946d43db6 100644
--- a/ports/esp32/modmachine.c
+++ b/ports/esp32/modmachine.c
@@ -58,7 +58,6 @@
     { MP_ROM_QSTR(MP_QSTR_sleep), MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep), MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep), MP_ROM_PTR(&machine_deepsleep_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle), MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_bootloader), MP_ROM_PTR(&machine_bootloader_obj) }, \
     \
     { MP_ROM_QSTR(MP_QSTR_disable_irq), MP_ROM_PTR(&machine_disable_irq_obj) }, \
@@ -283,13 +282,11 @@ STATIC mp_obj_t machine_unique_id(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_unique_id_obj, machine_unique_id);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     MP_THREAD_GIL_EXIT();
     taskYIELD();
     MP_THREAD_GIL_ENTER();
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_disable_irq(void) {
     uint32_t state = MICROPY_BEGIN_ATOMIC_SECTION();
diff --git a/ports/esp8266/modmachine.c b/ports/esp8266/modmachine.c
index b15515acd7..cce6b01ce7 100644
--- a/ports/esp8266/modmachine.c
+++ b/ports/esp8266/modmachine.c
@@ -45,7 +45,6 @@
     { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&machine_reset_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_reset_cause), MP_ROM_PTR(&machine_reset_cause_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_unique_id), MP_ROM_PTR(&machine_unique_id_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle), MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_sleep), MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep), MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep), MP_ROM_PTR(&machine_deepsleep_obj) }, \
@@ -102,14 +101,10 @@ STATIC mp_obj_t machine_unique_id(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_unique_id_obj, machine_unique_id);
 
-STATIC mp_obj_t machine_idle(void) {
-    uint32_t t = mp_hal_ticks_cpu();
+STATIC void mp_machine_idle(void) {
     asm ("waiti 0");
-    t = mp_hal_ticks_cpu() - t;
     ets_event_poll(); // handle any events after possibly a long wait (eg feed WDT)
-    return MP_OBJ_NEW_SMALL_INT(t);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     uint32_t max_us = 0xffffffff;
diff --git a/ports/mimxrt/modmachine.c b/ports/mimxrt/modmachine.c
index ecd79d2230..b0c41fe1af 100644
--- a/ports/mimxrt/modmachine.c
+++ b/ports/mimxrt/modmachine.c
@@ -67,7 +67,6 @@
     { MP_ROM_QSTR(MP_QSTR_RTC),                 MP_ROM_PTR(&machine_rtc_type) }, \
     MICROPY_PY_MACHINE_SDCARD_ENTRY \
     \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),           MP_ROM_PTR(&machine_deepsleep_obj) }, \
     \
     { MP_ROM_QSTR(MP_QSTR_disable_irq),         MP_ROM_PTR(&machine_disable_irq_obj) }, \
@@ -127,11 +126,9 @@ STATIC mp_obj_t machine_freq(void) {
 }
 MP_DEFINE_CONST_FUN_OBJ_0(machine_freq_obj, machine_freq);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     MICROPY_EVENT_POLL_HOOK;
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_deepsleep(size_t n_args, const mp_obj_t *args) {
     if (n_args != 0) {
diff --git a/ports/nrf/modules/machine/modmachine.c b/ports/nrf/modules/machine/modmachine.c
index b5d078ae51..3e3f185f6c 100644
--- a/ports/nrf/modules/machine/modmachine.c
+++ b/ports/nrf/modules/machine/modmachine.c
@@ -89,7 +89,6 @@
     { MP_ROM_QSTR(MP_QSTR_bootloader),         MP_ROM_PTR(&machine_bootloader_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_enable_irq),         MP_ROM_PTR(&machine_enable_irq_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_disable_irq),        MP_ROM_PTR(&machine_disable_irq_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle),               MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_sleep),              MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep),         MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),          MP_ROM_PTR(&machine_deepsleep_obj) }, \
@@ -196,11 +195,9 @@ NORETURN mp_obj_t machine_bootloader(size_t n_args, const mp_obj_t *args) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bootloader_obj, 0, 1, machine_bootloader);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     MICROPY_EVENT_POLL_HOOK;
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(void) {
     __WFE();
diff --git a/ports/qemu-arm/modmachine.c b/ports/qemu-arm/modmachine.c
index 1134ab4103..59694f92fc 100644
--- a/ports/qemu-arm/modmachine.c
+++ b/ports/qemu-arm/modmachine.c
@@ -32,3 +32,7 @@
 
 // This variable is needed for machine.soft_reset(), but the variable is otherwise unused.
 int pyexec_system_exit = 0;
+
+STATIC void mp_machine_idle(void) {
+    // Do nothing.
+}
diff --git a/ports/renesas-ra/modmachine.c b/ports/renesas-ra/modmachine.c
index 4617f0af0c..e0b34666fe 100644
--- a/ports/renesas-ra/modmachine.c
+++ b/ports/renesas-ra/modmachine.c
@@ -67,7 +67,6 @@
     { MP_ROM_QSTR(MP_QSTR_reset),               MP_ROM_PTR(&machine_reset_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_bootloader),          MP_ROM_PTR(&machine_bootloader_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_freq),                MP_ROM_PTR(&machine_freq_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_sleep),               MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep),          MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),           MP_ROM_PTR(&machine_deepsleep_obj) }, \
@@ -236,11 +235,9 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 4, machine_freq);
 // idle()
 // This executies a wfi machine instruction which reduces power consumption
 // of the MCU until an interrupt occurs, at which point execution continues.
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     __WFI();
-    return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     if (n_args != 0) {
diff --git a/ports/renesas-ra/modmachine.h b/ports/renesas-ra/modmachine.h
index 22d1fc475e..b8f8b631f2 100644
--- a/ports/renesas-ra/modmachine.h
+++ b/ports/renesas-ra/modmachine.h
@@ -47,7 +47,6 @@ MP_DECLARE_CONST_FUN_OBJ_0(machine_reset_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bootloader_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj);
 
-MP_DECLARE_CONST_FUN_OBJ_0(machine_idle_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_lightsleep_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_deepsleep_obj);
 
diff --git a/ports/rp2/modmachine.c b/ports/rp2/modmachine.c
index 6ec2811f98..65a5f75c58 100644
--- a/ports/rp2/modmachine.c
+++ b/ports/rp2/modmachine.c
@@ -54,7 +54,6 @@
     { MP_ROM_QSTR(MP_QSTR_bootloader),          MP_ROM_PTR(&machine_bootloader_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_freq),                MP_ROM_PTR(&machine_freq_obj) }, \
     \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep),          MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),           MP_ROM_PTR(&machine_deepsleep_obj) }, \
     \
@@ -121,11 +120,9 @@ STATIC mp_obj_t machine_freq(size_t n_args, const mp_obj_t *args) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 1, machine_freq);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     __wfe();
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     mp_int_t delay_ms = 0;
diff --git a/ports/samd/modmachine.c b/ports/samd/modmachine.c
index 9b2e88ba60..60b09cb0a3 100644
--- a/ports/samd/modmachine.c
+++ b/ports/samd/modmachine.c
@@ -64,7 +64,6 @@
     { MP_ROM_QSTR(MP_QSTR_Timer),               MP_ROM_PTR(&machine_timer_type) }, \
     MICROPY_PY_MACHINE_RTC_ENTRY \
     \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_disable_irq),         MP_ROM_PTR(&machine_disable_irq_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_enable_irq),          MP_ROM_PTR(&machine_enable_irq_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_reset_cause),         MP_ROM_PTR(&machine_reset_cause_obj) }, \
@@ -122,11 +121,9 @@ STATIC mp_obj_t machine_unique_id(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_unique_id_obj, machine_unique_id);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     MICROPY_EVENT_POLL_HOOK;
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_disable_irq(void) {
     uint32_t state = MICROPY_BEGIN_ATOMIC_SECTION();
diff --git a/ports/stm32/modmachine.c b/ports/stm32/modmachine.c
index fcdab9dfc1..8378fb3feb 100644
--- a/ports/stm32/modmachine.c
+++ b/ports/stm32/modmachine.c
@@ -102,7 +102,6 @@
     { MP_ROM_QSTR(MP_QSTR_bootloader),          MP_ROM_PTR(&machine_bootloader_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_freq),                MP_ROM_PTR(&machine_freq_obj) }, \
     MICROPY_PY_MACHINE_RNG_ENTRY \
-    { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_sleep),               MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_lightsleep),          MP_ROM_PTR(&machine_lightsleep_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_deepsleep),           MP_ROM_PTR(&machine_deepsleep_obj) }, \
@@ -381,11 +380,9 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 4, machine_freq);
 // idle()
 // This executies a wfi machine instruction which reduces power consumption
 // of the MCU until an interrupt occurs, at which point execution continues.
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     __WFI();
-    return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
 
 STATIC mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     if (n_args != 0) {
diff --git a/ports/stm32/modmachine.h b/ports/stm32/modmachine.h
index 096666eb5a..a234325fd7 100644
--- a/ports/stm32/modmachine.h
+++ b/ports/stm32/modmachine.h
@@ -39,7 +39,6 @@ MP_DECLARE_CONST_FUN_OBJ_0(machine_reset_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bootloader_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj);
 
-MP_DECLARE_CONST_FUN_OBJ_0(machine_idle_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_lightsleep_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_deepsleep_obj);
 MP_DECLARE_CONST_FUN_OBJ_0(machine_reset_cause_obj);
diff --git a/ports/stm32/modpyb.c b/ports/stm32/modpyb.c
index 0bf2d6a2c3..165c982f5d 100644
--- a/ports/stm32/modpyb.c
+++ b/ports/stm32/modpyb.c
@@ -65,6 +65,12 @@ STATIC mp_obj_t pyb_fault_debug(mp_obj_t value) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_fault_debug_obj, pyb_fault_debug);
 
+STATIC mp_obj_t pyb_idle(void) {
+    __WFI();
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_idle_obj, pyb_idle);
+
 #if MICROPY_PY_PYB_LEGACY
 
 // Returns the number of milliseconds which have elapsed since `start`.
@@ -144,7 +150,7 @@ STATIC const mp_rom_map_elem_t pyb_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_repl_info), MP_ROM_PTR(&pyb_set_repl_info_obj) },
     #endif
 
-    { MP_ROM_QSTR(MP_QSTR_wfi), MP_ROM_PTR(&machine_idle_obj) },
+    { MP_ROM_QSTR(MP_QSTR_wfi), MP_ROM_PTR(&pyb_idle_obj) },
     { MP_ROM_QSTR(MP_QSTR_disable_irq), MP_ROM_PTR(&machine_disable_irq_obj) },
     { MP_ROM_QSTR(MP_QSTR_enable_irq), MP_ROM_PTR(&machine_enable_irq_obj) },
     #if IRQ_ENABLE_STATS
diff --git a/ports/unix/modmachine.c b/ports/unix/modmachine.c
index 91e3e61340..9eacd5539f 100644
--- a/ports/unix/modmachine.c
+++ b/ports/unix/modmachine.c
@@ -36,14 +36,7 @@
 #define MICROPY_PAGE_MASK (MICROPY_PAGE_SIZE - 1)
 #endif
 
-#ifdef MICROPY_UNIX_MACHINE_IDLE
-#define MICROPY_PY_MACHINE_IDLE_ENTRY { MP_ROM_QSTR(MP_QSTR_idle), MP_ROM_PTR(&machine_idle_obj) },
-#else
-#define MICROPY_PY_MACHINE_IDLE_ENTRY
-#endif
-
 #define MICROPY_PY_MACHINE_EXTRA_GLOBALS \
-    MICROPY_PY_MACHINE_IDLE_ENTRY \
     { MP_ROM_QSTR(MP_QSTR_PinBase), MP_ROM_PTR(&machine_pinbase_type) }, \
 
 // This variable is needed for machine.soft_reset(), but the variable is otherwise unused.
@@ -80,10 +73,10 @@ uintptr_t mod_machine_mem_get_addr(mp_obj_t addr_o, uint align) {
     return addr;
 }
 
-#ifdef MICROPY_UNIX_MACHINE_IDLE
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
+    #ifdef MICROPY_UNIX_MACHINE_IDLE
     MICROPY_UNIX_MACHINE_IDLE
-    return mp_const_none;
+    #else
+    // Do nothing.
+    #endif
 }
-MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);
-#endif
diff --git a/ports/zephyr/modmachine.c b/ports/zephyr/modmachine.c
index 701420fadb..16109a3af8 100644
--- a/ports/zephyr/modmachine.c
+++ b/ports/zephyr/modmachine.c
@@ -43,7 +43,6 @@
 #define MICROPY_PY_MACHINE_EXTRA_GLOBALS \
     MICROPY_PY_MACHINE_RESET_ENTRY \
     { MP_ROM_QSTR(MP_QSTR_reset_cause), MP_ROM_PTR(&machine_reset_cause_obj) }, \
-    { MP_ROM_QSTR(MP_QSTR_idle), MP_ROM_PTR(&machine_idle_obj) }, \
     { MP_ROM_QSTR(MP_QSTR_Pin), MP_ROM_PTR(&machine_pin_type) }, \
 
 STATIC mp_obj_t machine_reset(void) {
@@ -59,8 +58,6 @@ STATIC mp_obj_t machine_reset_cause(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_reset_cause_obj, machine_reset_cause);
 
-STATIC mp_obj_t machine_idle(void) {
+STATIC void mp_machine_idle(void) {
     k_yield();
-    return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle);