diff --git a/arch/sim/src/up_idle.c b/arch/sim/src/up_idle.c
index 0106c29597..cfe4a7d6d0 100644
--- a/arch/sim/src/up_idle.c
+++ b/arch/sim/src/up_idle.c
@@ -106,15 +106,26 @@ void up_idle(void)
   sched_process_timer();
 #endif
 
-  /* Run the network if enabled */
+#if defined(CONFIG_DEV_CONSOLE) && !defined(CONFIG_SIM_UART_DATAPOST)
+  /* Handle UART data availability */
+
+  if (g_uart_data_available)
+    {
+      g_uart_data_available = 0;
+      simuart_post();
+    }
+#endif
+
 
 #ifdef CONFIG_NET
+  /* Run the network if enabled */
+
   netdriver_loop();
 #endif
 
+#ifdef CONFIG_PM
   /* Fake some power management stuff for testing purposes */
 
-#ifdef CONFIG_PM
   {
     static enum pm_state_e state = PM_NORMAL;
     enum pm_state_e newstate;
@@ -130,11 +141,11 @@ void up_idle(void)
   }
 #endif
 
+#if defined(CONFIG_SIM_WALLTIME) || defined(CONFIG_SIM_X11FB)
   /* Wait a bit so that the sched_process_timer() is called close to the
    * correct rate.
    */
 
-#if defined(CONFIG_SIM_WALLTIME) || defined(CONFIG_SIM_X11FB)
   (void)up_hostusleep(1000000 / CLK_TCK);
 
   /* Handle X11-related events */
@@ -142,9 +153,9 @@ void up_idle(void)
 #ifdef CONFIG_SIM_X11FB
   if (g_x11initialized)
     {
+#ifdef CONFIG_SIM_TOUCHSCREEN
        /* Drive the X11 event loop */
 
-#ifdef CONFIG_SIM_TOUCHSCREEN
       if (g_eventloop)
         {
           up_x11events();
diff --git a/arch/sim/src/up_internal.h b/arch/sim/src/up_internal.h
index da0c0c2bbe..5cfb715609 100644
--- a/arch/sim/src/up_internal.h
+++ b/arch/sim/src/up_internal.h
@@ -84,6 +84,10 @@
 #  undef CONFIG_RAMLOG_SYSLOG
 #endif
 
+/* The design for how we signal UART data availability is up in the air */
+
+#undef CONFIG_SIM_UART_DATAPOST
+
 /* Context Switching Definitions ******************************************/
 /* Storage order: %ebx, $esi, %edi, %ebp, sp, and return PC */
 
@@ -144,6 +148,10 @@ extern volatile int g_eventloop;
 #endif
 #endif
 
+#if defined(CONFIG_DEV_CONSOLE) && !defined(CONFIG_SIM_UART_DATAPOST)
+extern volatile int g_uart_data_available;
+#endif
+
 /**************************************************************************
  * Public Function Prototypes
  **************************************************************************/
diff --git a/arch/sim/src/up_simuart.c b/arch/sim/src/up_simuart.c
index cd14700d42..ba237fb7e7 100644
--- a/arch/sim/src/up_simuart.c
+++ b/arch/sim/src/up_simuart.c
@@ -50,6 +50,10 @@
 
 #define SIMUART_BUFSIZE 256
 
+/* The design for how we signal UART data availability is up in the air */
+
+#undef CONFIG_SIM_UART_DATAPOST
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -58,6 +62,14 @@ static char g_uartbuffer[SIMUART_BUFSIZE];
 static volatile int  g_uarthead;
 static volatile int  g_uarttail;
 
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifndef CONFIG_SIM_UART_DATAPOST
+volatile int g_uart_data_available;
+#endif
+
 /****************************************************************************
  * NuttX Domain Public Function Prototypes
  ****************************************************************************/
@@ -115,7 +127,9 @@ static void *simuart_thread(void *arg)
 
       if (nread == 1)
         {
+#ifdef CONFIG_SIM_UART_DATAPOST
           sched_lock();
+#endif
 
           /* Get the index to the next slot in the UART buffer */
 
@@ -146,10 +160,15 @@ static void *simuart_thread(void *arg)
                    * input.
                    */
 
+#ifdef CONFIG_SIM_UART_DATAPOST
                   simuart_post();
+#else
+                  g_uart_data_available = 1;
+#endif
                 }
             }
 
+#ifdef CONFIG_SIM_UART_DATAPOST
           /* REVISIT:  This is very weird and scary here.  When sched_unlock()
            * is called, we may do a lonjmp() style context switch meaning
            * that the logic will be run running on this thread! (but with a
@@ -159,6 +178,7 @@ static void *simuart_thread(void *arg)
            */
 
           sched_unlock();
+#endif
         }
     }