Yay for 8 bit microcontrollers! Um.. I mean 32-bit microcontrollers that pretend to be 8-bit controllers, but kick their butt! That, in a nutshell, is the awesomeness of the Teensy 3.1!
We are carrying the 3.1 version now. The RAM has quadrupled, from 16K to 64K. All digital pins are 5 volt tolerant on Teensy 3.1. However, the analog-only pins (A10-A14), AREF, Program, and Reset are 3.3V only. The Cortex-M4 core frequency is 72MHz (48MHz on the Teensy 3.0). Teensy 3.1 has a proper analog output. See full list of features.
What happened to 16-bit processors? Eh? Everybody skipped them? Gee, from 8-bit straight to 32-bit, and the Teensy USB V3.1 is an example of the substantial power you get for low cost these days. "BACK IN MAH DAY, we could've flown to the moon, balanced the budget, and beat the Russians into space if we had just one of these!"
The Paul & Robin team over at PJRC have been turning out some really clever stuff lately. Their latest iteration of the Teensy is quite impressive. It's a 32-bit processor ina tidy footprint that runs the AVR-GCC toolchain. Wait - it also runs in ARDUINO? Ok, we're even more impressed. This is shoe-horning some serious power into the very popular Arduino programming IDE. They've been active contributors to the Arduino project, so this team knows their stuff.
Ok, here's the low-down on the Teensy 3.1:
In short. WOW, what a shopping list of features! It's a fabulous little controller, using a well-proven and popular programming system, and it's a great value.
Sorry. You can't have them anymore. I'm going to keep them all on my R&D desk now...