Arduino Compatibility
		The Quub system was not initially conceived to be Arduino compatible, however many of the designed board's hardware is so close to the Arduinos that it make sense to make it so if possible. Therefore much work has been done to make the Quub hardware compatible with the Arduino system.
		DUINO-Quub Arduino compatibility
		The DUINO-Quub is not physically compatible with any of the Arduinos, however it almost identical at the hardware level as it uses an ATmega328 as the processor. Some differences are... LED13 - On the DUINO-Quub this signal is buffered before driving the LED, therefore you do not need to consider any loading on this signal. USB - The DUINO-Quub does not have an FTDI chip resident on the PCB, it is designed to connect to two different types of FTDI USB-serial bridge cables. Therefore applications that don't need USB don't pay for the extra hardware and the board can be much smaller.
		MEGA-Quub Arduino compatibility
		Obviously the MEGA-Quub is not physically compatible with any of the Arduinos either, however it is very close electrically. Feature wise it sits between a Duemilanove and a Mega. The following table highlights the main differences.   MEGA-Quub Duemilanove Mega Processor ATmega1284 ATmega328 ATmega1280 Flash 128k 32k 128k RAM 16k 2k 8k EEPROM 4k 512 4k IO 32 23 86 UARTS 2 1 4 Timers 4 3 6 ADC channels 8 6 16 Interrupts 2 3 16 Size 1.8x1.8" 2.7x2.1" 4x2.1"  The MEGA-Quub has the following advantages over the Duemilanove. 4x program memory. 8x RAM. 8x EEPROM. Extra 9 IO pins. Extra 2 analogue inputs. Extra hardware UART. Smaller size. Addressable "shields". Two "communications interface" areas for networking hardware. Hardware reset IC with brown-out detect. The MEGA-Quub is very similar to the Mega but with fewer UARTs and IO lines. The extra hardware UART (compared to the Duemilanove) is a big advantage as it allows a serial connection to the Arduino IDE as well as one to another device. Some other differences are... LED13 - On the MEGA-Quub this signal is buffered before driving the LED, therefore you do not need to consider any loading on this signal. Voltage regulator - The MEGA-Quub has provision for three different types of regulator for the 5v VCC board power. Pad/hole patterns allow either a linear SOT223 (preferred) or TO220 (if you get caught on the weekend without an SOT223 package) package linear regulator. These are standard but will run very hot if the VBAT level is too high so a third option is a TRACO TSR-1 series switching regulator which will provide currents up to 1A with VBATs of up to 36 volts without requiring a heatsink. USB - The MEGA-Quub does not have an FTDI chip resident on the PCB, it is designed to connect to two different types of FTDI USB-serial bridge cables. Therefore applications that don't need USB don't pay for the extra hardware and once an application is complete there is no USB hardware occupying space on the PCB. SERIAL - If a USB cable is present then digital 0 and 1 are dedicated to the USB connection in the same manner as on a Duemilanove. If the cable is not present then you can use 0 and 1 for any purpose you like including a serial link. If the final application does in fact require USB though this is still possible. Digital pins 2 and 3 can be used in the standard manner but they are also connected to UART 1 and therefore provide a second hardware serial connection. PWM - Not determined yet. SPI - The SS, MOSI, MISO and SCK signals are on digital IO pins 20, 21, 22 and 23. I2C - SDA and SCK are connected to digital IO pins 8 and 9. INT - Three interrupts are available on digital IO pins 2, 3 and 18. As IO-18 is also the Rx pin of UART 1 this interrupt cannot be used if the UART is also being used unless its function is to interrupt the processor on a change of state for the Rx line.
		Smart stackable Arduino compatibility
		Some smart stackables can also be used as Arduino clones, they feature an ATmega328 and a 6-way FTDI connector with reset capacitor and 500mA fuse. For example the Quub-HMI-LED has 5 tactile pushbuttons, a 3-digit LED display, a piezo buzzer, 2 analogue, 3 analogue/digital and 1 digital IO lines, plus onboard regulator capable of handling up to 30 volts. Use the IO directly or couple it to several IONs to make an intelligent meter or monitor for battery banks, fridges etc. And all programmable from the Arduino IDE.
		Arduino shield compatibility
		Physically the Quub format is not compatible with the Arduino Duemilanove/Mega shields, however as the header rows on the shields are spaced 1.9" apart and the Quub is only 1.8" square a Quub processor will fit quite nicely "inside" the shield headers. Therefore an adapter board (the Ardaptor) has been designed so any Quub processor can take advantage of the huge variety of available Arduino shields. Another, the Quub-4DIF, has a real time clock, can handle 2Gb of SD storage and an LCD touch screen, that would make a very tidy data logger for example. Or maybe a speedo and instrument panel for a vehicle.
		The Ardaptor
		The Ardaptor is a Duemilanove-sized PCB with the standard Arduino header as well as the Quub headers. This allows for the plugging in of Arduino shields on one side and a Quub system on the other. The two systems can co-exist, therefore any Quub core processor can interface with standard Arduino shields and it's own stackables at the same time. NOTE: Quub stackables can be addressable and in general there are no pin contention issues. This is not the case with Arduino shields, so there may be conflicts between shields and stackables depending on the pins used by them.     The Ardaptor also has a header for connecting to the 9 digital and 2 analogue IO pins the MEGA-Quub has extra to the Duemilanove, a DC barrel jack and a 6-way SIL header for connecting an FTDI USB-serial bridge cable.
		Arduino software compatibility
		The DUINO-Quub, Quub-HMI-LED and Quub-4DIF feature Atmega328 processors and should therefore be immediately compatible with the Arduino programming environment. Also with a little effort the ATmega1284-based MEGA-Quub could also be made compatible.