Merge pull request #1920 from devsaurus/uart_flush

ESP32: Establish flushing of uart to leverage buffering putchar().

components/base_nodemcu/uart.c

@@ -131,6 +131,7 @@ static int uart_write( lua_State* L )
       if( len > 255 )
         return luaL_error( L, "invalid number" );
       platform_uart_send( id, (uint8_t)len );
+      platform_uart_flush( id );
     }
     else
     {
@@ -138,6 +139,7 @@ static int uart_write( lua_State* L )
       buf = lua_tolstring( L, s, &len );
       for( i = 0; i < len; i ++ )
         platform_uart_send( id, buf[ i ] );
+      platform_uart_flush( id );
     }
   }
   return 0;

components/platform/include/platform.h

@@ -72,6 +72,7 @@ enum
 static inline int platform_uart_exists( unsigned id ) { return id < NUM_UART; }
 uint32_t platform_uart_setup( unsigned id, uint32_t baud, int databits, int parity, int stopbits );
 void platform_uart_send( unsigned id, uint8_t data );
+void platform_uart_flush( unsigned id );
 int platform_uart_set_flow_control( unsigned id, int type );
 
 

components/platform/platform.c

@@ -68,6 +68,12 @@ void platform_uart_send( unsigned id, uint8_t data )
     putchar (data);
 }
 
+void platform_uart_flush( unsigned id )
+{
+  if (id == CONSOLE_UART)
+    fflush (stdout);
+}
+
 // *****************************************************************************
 // Sigma-Delta platform interface