Avr isp connection with loaded pins

Question

Sorry for asking a non-programming question here. I am making my first circuit with an avrTiny . All my GPIO pins are loaded (resistor + led) . How do i connect my isp header with the load still on the pins

Answer 1

You can connect each ISP header pin between corresponding AVR pin and it's load. If the load is within spec, all should be fine.

 ISP PIN
    ^
    |
 г--*---->AVR PIN
 |
 R
 |
LED
 |
GND

Answer 2

I connect the ISP pins right to the microcontroller pins, then any shared devices on the same bus/pins go through 1k ohm series resistors. That way if one of the connected devices is driving the net at a different level than the ISP, there's a load to prevent a direct short.

Here is an AVR Freaks form post about this in more detail:
http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=58470