Arduino Mega was released today. I already ordered mine from lawicel. As stated in arduino mega page: It has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. I definitely will use those additional USARTS. The lack of a second USART was the main drawback of previous Arduinos for me.
I’ve been playing with the Arduino sleep modes and i wanted to be able to wake up from the sleep when receiving data on the serial port. Mainly, because in my project I’m using the XBee in the API mode and the tricks exposed in http://www.arduino.cc/playground/Learning/ArduinoSleepCode and http://www.libelium.com/squidbee/index.php?title=Save_power_in_SquidBee_-_sleep_mode involve putting Arduino in SLEEP_MODE_PWR_DOWN and using an extra pin on the arduino to monitor the RX pin and detecting LOW. I didn’t like that much that solution so I started to look into other ways of doing it without using an extra pin and without risk of losing data in the serial interface. Because as I understood it using SLEEP_MODE_PWR_DOWN requires to send first a burst of data to the serial interface in order to wake up the arduino. And it takes a while for the Arduino to become fully functional so that means that you will lose/miss data in the serial interface. That was something that didn’t fit my project. ...