Simply use pin 10 to reset the target. It works for all Arduino's and allows the same "ArduinoISP shield" to be used on all of them. Such a shield has an ISP connector that: - wires MISO,MOSI, SCK, GND and 5V to the ISP connector of the programming Arduino - wires RESET to pin 10 of the programming Arduino.

Peter Van Hoyweghen · Peter Van Hoyweghen · commit 93b31b6cfa72 · 2015-07-13T21:21:57.000+02:00
diff --git a/build/shared/examples/11.ArduinoISP/ArduinoISP/ArduinoISP.ino b/build/shared/examples/11.ArduinoISP/ArduinoISP/ArduinoISP.ino
@@ -7,7 +7,7 @@
 // using the following arduino pins:
 //
 // pin name:    not-mega:         mega(1280 and 2560)
-// slave reset: 10:               53
+// slave reset: 10:               10
 // MOSI:        11:               51
 // MISO:        12:               50
 // SCK:         13:               52
@@ -45,7 +45,8 @@
 
 #include "SPI.h"
 #include "pins_arduino.h"
-#define RESET     SS
+// Use pin 10 to reset the target
+#define RESET     10
 
 #define LED_HB    9
 #define LED_ERR   8
