Does a safe USB programmer exist for 3.3V boards?

Development Tools IDE 1.x
1

I've looked at several already like the USBASP 5V/3.3V and decided that they are not well-suited for 3.3V target operation. While you can select the target V+ to be 3.3V, the signal voltages coming from the USB interface processor still pump out +5V to the target board, which violates the target inputs' max ratings.

I found the Yuki variant of the USBASP: http://yuki-lab.jp/hw/usbasp/usbasp-circuit.png

Yuki makes an honest attempt at voltage translation, but using a buffer-translator in place of the HC part makes more sense to me.

Any thoughts?

2

The avrisp mkII is a safe one. It doesn't power the target but it does read the Vcc voltage from the target to set it's I/O pin voltage levels.

Lefty