From 78a0b12ed932f0f2d6bb991d99a88c3e222e32f0 Mon Sep 17 00:00:00 2001
From: Ivan Grokhotkov <igrokhotkov@gmail.com>
Date: Fri, 9 Jan 2015 02:33:42 +0300
Subject: [PATCH] Add method to use GPIO13 and GPIO15 as UART RX and TX

---
 build/shared/lib/keywords.txt                 |  1 +
 .../esp8266/cores/esp8266/HardwareSerial.cpp  | 19 +++++++++++++++++++
 .../esp8266/cores/esp8266/HardwareSerial.h    |  1 +
 3 files changed, 21 insertions(+)

diff --git a/build/shared/lib/keywords.txt b/build/shared/lib/keywords.txt
index d77a4b10c..e5bc96533 100644
--- a/build/shared/lib/keywords.txt
+++ b/build/shared/lib/keywords.txt
@@ -179,6 +179,7 @@ println	KEYWORD2	Serial_Println
 available	KEYWORD2	Serial_Available
 availableForWrite	KEYWORD2
 flush	KEYWORD2	Serial_Flush
+swap	KEYWORD2
 setTimeout	KEYWORD2
 find	KEYWORD2
 findUntil	KEYWORD2
diff --git a/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.cpp b/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.cpp
index 3a29c6701..1e638b0a7 100644
--- a/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.cpp
+++ b/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.cpp
@@ -193,6 +193,18 @@ void ICACHE_FLASH_ATTR uart0_uninit(uart_t* uart)
     os_free(uart);
 }
 
+#define FUNC_U0CTS    4
+#define FUNC_U0RTS    4
+
+void ICACHE_FLASH_ATTR uart0_swap(uart_t* uart)
+{
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_U0CTS);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDO_U, FUNC_U0RTS);
+    //SWAP PIN : U0TXD<==>U0RTS(MTDO, GPIO15) , U0RXD<==>U0CTS(MTCK, GPIO13)
+    SET_PERI_REG_MASK(0x3ff00028 , BIT2);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, FUNC_GPIO1);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0RXD_U, FUNC_GPIO3);
+}
 
 void ICACHE_FLASH_ATTR
 uart_ignore_char(char c)
@@ -251,6 +263,13 @@ void ICACHE_FLASH_ATTR HardwareSerial::end()
     _tx_buffer = 0;
 }
 
+void ICACHE_FLASH_ATTR HardwareSerial::swap()
+{
+    uart0_swap(_uart);
+    pinMode(1, INPUT);
+    pinMode(3, INPUT);
+}
+
 void ICACHE_FLASH_ATTR HardwareSerial::setDebugOutput(bool en)
 {
     uart_set_debug(en);
diff --git a/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.h b/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.h
index c934d9c58..143dd3061 100644
--- a/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.h
+++ b/hardware/arduino/esp8266/cores/esp8266/HardwareSerial.h
@@ -69,6 +69,7 @@ public:
     void begin(unsigned long baud) { begin(baud, 0); }
     void begin(unsigned long, uint8_t);
     void end();
+    void swap();  //use GPIO13 and GPIO15 as RX and TX
     int available(void) override;
     int peek(void) override;
     int read(void) override;