diff --git a/ports/sh/main.c b/ports/sh/main.c
index 0b2543eae..5e6cbb36c 100644
--- a/ports/sh/main.c
+++ b/ports/sh/main.c
@@ -18,7 +18,6 @@
 #include <gint/keyboard.h>
 #include <gint/kmalloc.h>
 #include <gint/fs.h>
-#include <gint/timer.h>
 
 #include <justui/jscene.h>
 #include <justui/jlabel.h>
@@ -56,14 +55,12 @@ struct pe_globals {
 
 // TODO: Put pe_globals in a header for use by the loop hook in mpconfigport.h
 widget_shell *pe_shell;
+/* Whether a delayed dupdate has been scheduled asynchronously. */
+bool pe_dupdate_scheduled;
 
 struct pe_globals PE = { 0 };
 
 
-// TODO : make this more clean by putting these globals into pe_globals and
-// making this accessible to modules
-bool is_refreshed_required = false;
-
 //=== Hook for redirecting stdout/stderr to the shell ===//
 
 static ssize_t stdouterr_write(void *data, void const *buf, size_t size)
@@ -178,13 +175,17 @@ void pe_enter_graphics_mode(void)
     PE.shell->widget.update = 0;
 }
 
-void pe_refresh_graphics(void)
+void pe_schedule_dupdate(void)
+{
+    pe_enter_graphics_mode();
+    pe_dupdate_scheduled = true;
+}
+
+void pe_dupdate(void)
 {
-    /* refresh graphical output on request by setting
-    is_refresh_graphics to true */
     dupdate();
     pe_debug_run_videocapture();
-    is_refreshed_required = false;
+    pe_dupdate_scheduled = false;
 }
 
 void pe_draw(void)
@@ -205,8 +206,7 @@ void pe_draw(void)
     dsubimage(377, 207, &img_modifier_states, 16*icon, 0, 15, 14,
         DIMAGE_NONE);
 #endif
-    dupdate();
-    pe_debug_run_videocapture();
+    pe_dupdate();
 }
 
 //=== Application control functions ===//
diff --git a/ports/sh/modcasioplot.c b/ports/sh/modcasioplot.c
index abda99289..b032afa31 100644
--- a/ports/sh/modcasioplot.c
+++ b/ports/sh/modcasioplot.c
@@ -12,6 +12,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+extern void pe_enter_graphics_mode(void);
+extern void pe_dupdate(void);
+
 #ifdef FX9860G
 extern font_t font_4x4;
 extern font_t font_4x6;
@@ -70,10 +73,8 @@ static mp_obj_t init(void)
 
 static mp_obj_t show_screen(void)
 {
-    void pe_enter_graphics_mode(void);
     pe_enter_graphics_mode();
-    dupdate();
-    pe_debug_run_videocapture();
+    pe_dupdate();
     return mp_const_none;
 }
 
diff --git a/ports/sh/modgint.c b/ports/sh/modgint.c
index 219d1c0ca..62dedd7e0 100644
--- a/ports/sh/modgint.c
+++ b/ports/sh/modgint.c
@@ -19,7 +19,8 @@
 #include <gint/drivers/keydev.h>
 #include <stdlib.h>
 
-void pe_enter_graphics_mode(void);
+extern void pe_enter_graphics_mode(void);
+extern void pe_dupdate(void);
 
 #define FUN_0(NAME) \
     MP_DEFINE_CONST_FUN_OBJ_0(modgint_ ## NAME ## _obj, modgint_ ## NAME)
@@ -230,8 +231,7 @@ STATIC mp_obj_t modgint_dclear(mp_obj_t arg1)
 STATIC mp_obj_t modgint_dupdate(void)
 {
     pe_enter_graphics_mode();
-    dupdate();
-    pe_debug_run_videocapture();
+    pe_dupdate();
     return mp_const_none;
 }
 
diff --git a/ports/sh/mpconfigport.h b/ports/sh/mpconfigport.h
index 5fcda7f5e..bccb1f03e 100644
--- a/ports/sh/mpconfigport.h
+++ b/ports/sh/mpconfigport.h
@@ -109,11 +109,11 @@ void pe_after_python_exec(
 /* Command executed regularly during execution */
 extern void pe_draw(void);
 extern widget_shell *pe_shell;
-extern void pe_refresh_graphics(void);
-extern bool is_refreshed_required;
+extern void pe_dupdate(void);
+extern bool pe_dupdate_scheduled;
 #define MICROPY_VM_HOOK_LOOP \
     { if(pe_shell->widget.update) pe_draw(); \
-      if(is_refreshed_required) pe_refresh_graphics(); }
+      if(pe_dupdate_scheduled) pe_dupdate(); }
 
 /* extra built in names to add to the global namespace
 #define MICROPY_PORT_BUILTINS \
diff --git a/ports/sh/numworks/modkandinsky.c b/ports/sh/numworks/modkandinsky.c
index 7f57bef68..de0f88617 100644
--- a/ports/sh/numworks/modkandinsky.c
+++ b/ports/sh/numworks/modkandinsky.c
@@ -15,10 +15,11 @@
 #include <stdlib.h>
 #include <string.h>
 
+extern void pe_schedule_dupdate(void);
+
 extern font_t numworks;
 
 static bool is_dwindowed;
-extern bool is_refreshed_required;
 
 #define NW_MAX_X 320
 #define NW_MAX_Y 222
@@ -57,7 +58,7 @@ extern bool is_refreshed_required;
 // There are possibly some others to be listed correctly
 
 static int callback(void) {
-  is_refreshed_required = true;
+  pe_schedule_dupdate();
   return TIMER_CONTINUE;
 }