7 files changed, 47 insertions, 7 deletions
diff --git a/ports/atmel-samd/background.c b/ports/atmel-samd/background.c
index 519d0eeec..a8c4e3891 100644
--- a/ports/atmel-samd/background.c
+++ b/ports/atmel-samd/background.c
@@ -27,6 +27,7 @@
 
 #include "audio_dma.h"
 #include "tick.h"
+#include "supervisor/filesystem.h"
 #include "supervisor/usb.h"
 
 #include "py/runtime.h"
@@ -53,6 +54,7 @@ void run_background_tasks(void) {
     #if CIRCUITPY_NETWORK
     network_module_background();
     #endif
+    filesystem_background();
     usb_background();
     assert_heap_ok();
 
diff --git a/ports/nrf/background.c b/ports/nrf/background.c
index 69c76fd06..ea6e846b3 100644
--- a/ports/nrf/background.c
+++ b/ports/nrf/background.c
@@ -25,6 +25,7 @@
  */
 
 #include "py/runtime.h"
+#include "supervisor/filesystem.h"
 #include "supervisor/usb.h"
 #include "supervisor/shared/stack.h"
 
@@ -33,6 +34,7 @@
 #endif
 
 void run_background_tasks(void) {
+    filesystem_background();
     usb_background();
 
     #ifdef CIRCUITPY_DISPLAYIO
diff --git a/ports/nrf/tick.c b/ports/nrf/tick.c
index cdd329f71..6d8fd13e0 100644
--- a/ports/nrf/tick.c
+++ b/ports/nrf/tick.c
@@ -27,6 +27,7 @@
 #include "tick.h"
 
 #include "supervisor/shared/autoreload.h"
+#include "supervisor/filesystem.h"
 #include "shared-module/gamepad/__init__.h"
 #include "shared-bindings/microcontroller/Processor.h"
 #include "nrf.h"
@@ -39,14 +40,17 @@ void SysTick_Handler(void) {
     // (every millisecond).
     ticks_ms += 1;
 
-    #ifdef CIRCUITPY_AUTORELOAD_DELAY_MS
-        autoreload_tick();
-    #endif
-    #ifdef CIRCUITPY_GAMEPAD_TICKS
+#if CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS > 0
+    filesystem_tick();
+#endif
+#ifdef CIRCUITPY_AUTORELOAD_DELAY_MS
+    autoreload_tick();
+#endif
+#ifdef CIRCUITPY_GAMEPAD_TICKS
     if (!(ticks_ms & CIRCUITPY_GAMEPAD_TICKS)) {
         gamepad_tick();
     }
-    #endif
+#endif
 }
 
 void tick_init() {
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index e96d811ac..be97b0a51 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -597,6 +597,7 @@ void run_background_tasks(void);
 #define MICROPY_VM_HOOK_RETURN run_background_tasks();
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
+#define CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS 1000
 #define CIRCUITPY_BOOT_OUTPUT_FILE "/boot_out.txt"
 
 #endif  // __INCLUDED_MPCONFIG_CIRCUITPY_H
diff --git a/supervisor/filesystem.h b/supervisor/filesystem.h
index 76f235f47..c7c951a5e 100644
--- a/supervisor/filesystem.h
+++ b/supervisor/filesystem.h
@@ -31,6 +31,10 @@
 
 #include "extmod/vfs_fat.h"
 
+extern volatile bool filesystem_flush_requested;
+
+void filesystem_background(void);
+void filesystem_tick(void);
 void filesystem_init(bool create_allowed, bool force_create);
 void filesystem_flush(void);
 bool filesystem_present(void);
diff --git a/supervisor/shared/autoreload.c b/supervisor/shared/autoreload.c
index 2a7fd1e9d..14b21902c 100644
--- a/supervisor/shared/autoreload.c
+++ b/supervisor/shared/autoreload.c
@@ -29,9 +29,10 @@
 #include "py/mphal.h"
 #include "py/reload.h"
 
-volatile uint32_t autoreload_delay_ms = 0;
-bool autoreload_enabled = false;
+static volatile uint32_t autoreload_delay_ms = 0;
+static bool autoreload_enabled = false;
 static bool autoreload_suspended = false;
+
 volatile bool reload_requested = false;
 
 inline void autoreload_tick() {
diff --git a/supervisor/shared/filesystem.c b/supervisor/shared/filesystem.c
index 0ef978ef2..68c6f4749 100644
--- a/supervisor/shared/filesystem.c
+++ b/supervisor/shared/filesystem.c
@@ -37,6 +37,30 @@
 static mp_vfs_mount_t _mp_vfs;
 static fs_user_mount_t _internal_vfs;
 
+static volatile uint32_t filesystem_flush_interval_ms = CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS;
+volatile bool filesystem_flush_requested = false;
+
+void filesystem_background(void) {
+    if (filesystem_flush_requested) {
+        filesystem_flush();
+        filesystem_flush_requested = false;
+    }
+}
+
+inline void filesystem_tick(void) {
+    if (filesystem_flush_interval_ms == 0) {
+        // 0 means not turned on.
+        return;
+    }
+    if (filesystem_flush_interval_ms == 1) {
+        filesystem_flush_requested = true;
+        filesystem_flush_interval_ms = CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS;
+    } else {
+        filesystem_flush_interval_ms--;
+    }
+}
+
+
 static void make_empty_file(FATFS *fatfs, const char *path) {
     FIL fp;
     f_open(fatfs, &fp, path, FA_WRITE | FA_CREATE_ALWAYS);
@@ -91,6 +115,8 @@ void filesystem_init(bool create_allowed, bool force_create) {
 }
 
 void filesystem_flush(void) {
+    // Reset interval before next flush.
+    filesystem_flush_interval_ms = CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS;
     supervisor_flash_flush();
 }