Teensy 3.0 support for our TWI/I2C products
PJRC, creator of the Teensy line of Arduino compatible boards with native USB support (the forebear to the Arduino Leonardo) recently ran a Kickstarter project. The project was the new Teensy 3.0, with an ARM Cortex-M4 processor (32 bit, 96 Mhz, 128 kByte flash etc etc). It was successful, and a special version of the Arduino-1.0.1 IDE was released to support the board.
Akafugu pledged and received a few boards recently. Naturally, one of the first things we tried was to see if our TWI/I2C boards would work properly. Turns out there was little need for worry, all our TWI/I2C products (null, null, null and null) are compatible with Teensy 3.0 without any library or source code changes. (our libraries are written using the Wire library, which has been ported to the ARM processor of the Teensy 3.0 by PJRC)
The Teensy 3.0 is a 3.3V board, meaning that SDA and SCL are at this level. Our boards work fine with this, and you can still connect VCC to the 5V port to get better display brighness on TWIDisplay and TWILCD. The RTC board should be run from 3.3V VCC.