USB AVR Programmer power to device

The USB AVR Programmer does not connect the 5V from USB to the VDD pin on the programming header. Clearly there was a reason for this as many other programmers do this. I have successfully programmed devices using a 2nd USB cord hacked to provide 5V to the circuit which in turn feeds back into the programmer. Does anyone see a problem with soldering a pin header to the programmer that allows me to optionally send 5V to the circuit with a jumper? I am planning on connecting near the USB port so I’m not pulling all the power thru the small traces.

I believe the paperwork states that the programmer tells the host That it only needs the default .1A, it would be nice if the configuration utility or driver could be updated in the future to allow the device to negotiate for a higher limit if desired. Standard windows configuration will tolerate unauthorized power draw in most power plans, but it would be nice to avoid problems on machines with stingy power settings. Additionally, adding space to the PCB in a future rev for this 2 pin header could be nice.


We do give you access to the bus voltage (next to TX and RX pins), so you could make the connection from that pin to the target VDD pin fairly easily. We don’t have that connection on the board since managing it well would be complicated, and making a direct connection could be bad if the target isn’t tolerant of that.

We’d have to make significant changes to the firmware to support configurable current limits, so we don’t think it’s worth it right now since it probably won’t affect much, anyway.

- Jan