Since I need many Analog IO ports, I bought a MEGA (the "old" version with 1280) and a Pro mini as "extension". I want to connect both using the serial pour on the Pro mini to an "additional" serial on Mega (e.g. Serial2). This also means that to upload the Pro mini sketch, I should be able to use the MEGA as ISP. But is it possible ?
I found in the example the "ArduinoISP" sketch apparently last changed 2009. The Tutorial page http://arduino.cc/en/Tutorial/ArduinoISP
talks about changing the bootloader, but not the sketch ! The other page, http://arduino.cc/en/Tutorial/ArduinoISP
seems to do some weird things outside of the IDE, which would not be needed in may case (I guess) And these are using the 3-wire SPI interface, while the bootloader is supposed to use the serial interface, right ?
I've also found http://arduino.cc/en/Tutorial/MultiSerialMega
that shows how to replicate from one serial to another, but that won't work either. Any idea how to solve that problem ?
Can anyone clarify how I can do this ?