Accept both named constant and ADC channel number in analogRead (#1766)

Author: igrr

cores/esp8266/core_esp8266_wiring_analog.c

@@ -1,9 +1,9 @@
-/* 
+/*
   analog.c - analogRead implementation for esp8266
 
   Copyright (c) 2015 Hristo Gochkov. All rights reserved.
   This file is part of the esp8266 core for Arduino environment.
- 
+
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
@@ -17,20 +17,22 @@
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-  
-  
+
+
   18/06/2015 analogRead bugfix by Testato
 */
 
 #include "wiring_private.h"
 #include "pins_arduino.h"
 
 
-extern int __analogRead(uint8_t pin) {
-  if(pin == 17){
-    return system_adc_read();
-  }
-  return digitalRead(pin) * 1023;
+extern int __analogRead(uint8_t pin)
+{
+    // accept both A0 constant and ADC channel number
+    if(pin == 17 || pin == 0) {
+        return system_adc_read();
+    }
+    return digitalRead(pin) * 1023;
 }
 
 extern int analogRead(uint8_t pin) __attribute__ ((weak, alias("__analogRead")));