You are basically describing an Espruino WiFi without the WiFi on it... Would one of them do you? It's not like you have to turn WiFi on: http://www.espruino.com/WiFi
I think next on my list is probably a Bluetooth LE device on a 0.1" breakout board. There wouldn't be USB, but there's some fancy temperature-based drift correction in the RTC so it's actually pretty decent.
What about adding bluetooth LE to the Espruino WIFI? That way it could act as a 'relay' for the Puck . (the puck only needs a coin battery whereas the wifi needs something more robust)...
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
You are basically describing an Espruino WiFi without the WiFi on it... Would one of them do you? It's not like you have to turn WiFi on: http://www.espruino.com/WiFi
I think next on my list is probably a Bluetooth LE device on a 0.1" breakout board. There wouldn't be USB, but there's some fancy temperature-based drift correction in the RTC so it's actually pretty decent.