Added uart.alt(n) to swap to use alternate rx/tx lines.

if n = 0 -> std pinout.
if n != 0 -> alternate pinout (gpio13 and gpio15)

app/driver/uart.c

@@ -21,6 +21,10 @@
 #ifndef FUNC_U0RXD
 #define FUNC_U0RXD 0
 #endif
+#ifndef FUNC_U0CTS
+#define FUNC_U0CTS                      4
+#endif
+
 
 // For event signalling
 static uint8 task = USER_TASK_PRIO_MAX;
@@ -75,6 +79,39 @@ uart_config(uint8 uart_no)
     SET_PERI_REG_MASK(UART_INT_ENA(uart_no), UART_RXFIFO_FULL_INT_ENA);
 }
 
+
+
+/******************************************************************************
+ * FunctionName : uart0_alt
+ * Description  : Internal used function
+ *                UART0 pins changed to 13,15 if 'on' is set, else set to normal pins
+ * Parameters   : on - 1 = use alternate pins, 0 = use normal pins
+ * Returns      : NONE
+*******************************************************************************/
+void ICACHE_FLASH_ATTR
+uart0_alt(uint8 on)
+{
+    if (on)
+    {
+        PIN_PULLUP_DIS(PERIPHS_IO_MUX_MTDO_U);
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDO_U, FUNC_U0RTS);
+        PIN_PULLUP_EN(PERIPHS_IO_MUX_MTCK_U);
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_U0CTS);
+        // now make RTS/CTS behave as TX/RX
+        IOSWAP |= (1 << IOSWAPU0);
+    }
+    else
+    {
+        PIN_PULLUP_DIS(PERIPHS_IO_MUX_U0TXD_U);
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, FUNC_U0TXD);
+        PIN_PULLUP_EN(PERIPHS_IO_MUX_U0RXD_U);
+        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0RXD_U, FUNC_U0RXD);
+        // now make RX/TX behave as TX/RX
+        IOSWAP &= ~(1 << IOSWAPU0);
+    }
+}
+
+
 /******************************************************************************
  * FunctionName : uart_tx_one_char
  * Description  : Internal used function

app/include/driver/uart.h

@@ -102,6 +102,7 @@ typedef struct {
 } UartDevice;
 
 void uart_init(UartBautRate uart0_br, UartBautRate uart1_br, uint8 task_prio, os_signal_t sig_input);
+void uart0_alt(uint8 on);
 void uart0_sendStr(const char *str);
 void uart0_putc(const char c);
 void uart0_tx_buffer(uint8 *buf, uint16 len);

app/include/driver/uart_register.h

@@ -125,4 +125,17 @@
 
 #define UART_DATE( i )                          (REG_UART_BASE( i ) + 0x78)
 #define UART_ID( i )                            (REG_UART_BASE( i ) + 0x7C)
+
+#define ESP8266_DREG(addr) *((volatile uint32_t *)(0x3FF00000+(addr)))
+
+//IO SWAP Register
+#define IOSWAP    ESP8266_DREG(0x28)
+#define IOSWAPU   0 //Swaps UART
+#define IOSWAPS   1 //Swaps SPI
+#define IOSWAPU0  2 //Swaps UART 0 pins (u0rxd <-> u0cts), (u0txd <-> u0rts)
+#define IOSWAPU1  3 //Swaps UART 1 pins (u1rxd <-> u1cts), (u1txd <-> u1rts)
+#define IOSWAPHS  5 //Sets HSPI with higher prio
+#define IOSWAP2HS 6 //Sets Two SPI Masters on HSPI
+#define IOSWAP2CS 7 //Sets Two SPI Masters on CSPI
+
 #endif // UART_REGISTER_H_INCLUDED

app/modules/uart.c

@@ -116,6 +116,17 @@ static int uart_setup( lua_State* L )
   return 1;
 }
 
+// Lua: alt( set )
+static int uart_alt( lua_State* L )
+{
+  unsigned set;
+  
+  set = luaL_checkinteger( L, 1 );
+
+  platform_uart_alt( set );
+  return 0;
+}
+
 // Lua: write( id, string1, [string2], ..., [stringn] )
 static int uart_write( lua_State* L )
 {
@@ -154,6 +165,8 @@ const LUA_REG_TYPE uart_map[] =
   { LSTRKEY( "setup" ),  LFUNCVAL( uart_setup ) },
   { LSTRKEY( "write" ), LFUNCVAL( uart_write ) },
   { LSTRKEY( "on" ), LFUNCVAL( uart_on ) },
+  { LSTRKEY( "alt" ), LFUNCVAL( uart_alt ) },
+
 #if LUA_OPTIMIZE_MEMORY > 0
 
 #endif

app/platform/platform.c

@@ -251,6 +251,14 @@ uint32_t platform_uart_setup( unsigned id, uint32_t baud, int databits, int pari
   return baud;
 }
 
+// if set=1, then alternate serial output pins are used. (15=rx, 13=tx)
+void platform_uart_alt( int set )
+{
+    uart0_alt( set );
+    return;
+}
+
+
 // Send: version with and without mux
 void platform_uart_send( unsigned id, u8 data ) 
 {