ATMega32U4 PE6 / INT6 ?

Does anybody have experience with hardware interrupts on the ATMega32U4? I'm trying to find out what's going on with PE6 (D7 in Leonardo-speak).

The data sheet (http://www.atmel.com/Images/doc7766.pdf) says it's a true External Interrupt, not just the standard Pin Change interrupt that the other pins can use, but all the documentation I've seen on the web says there's only 4 hardware interrupts (interrupts 0-3 on pins PD0 - PD3 / Leonardo D0 - D3).

I hope to build one of Crossroads' Leonardino this weekend to see for myself, but while I'm waiting for parts I'm designing a new circuit that will need need PD0 - PD3 for the UART and I2C, but will also need a pin for external interrupt.

Thanks,

Chris

Assuming most of the Teensy features apply here is the best reference for using the 32U4 that I know of: http://www.pjrc.com/teensy/

http://www.pjrc.com/teensy/pins.html

Check this out. It might help http://propaneandelectrons.com/blog/int6-on-arduino-leonardo-atmega32u4