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Microcontroller Programming » AVRISP mkII trouble!

July 05, 2012
by rmore
rmore's Avatar

Hi All!

Unfortunately I am still stuck trying to figure out how to make my AVRISP mkII to work!

As an update - the blinking orange light was resolved by 1. Updating the firmware manually 2. Introducing a 10k ohm pull-up resistor on the reset line - between reset and +5V bus. (although i think the orange blinking problem was solved mostly by the second point above)

Now I see both the green lights on. So I should be all set to go. But first of all i cannot read the signature. So I lower the ISP frequency to the lowest Hertz value. This still does not help me.

Then I notice something fishy. Whenever I hit 'Read Signature' or 'Program', I see the green LED on programmer momentarily turn red. So I check voltage on reset line and the others and sure enough I see the voltage momentarily drop down to a low number.

So I am feeling that this is an issue that the programmer does not get power from target momentarily when it enters the programming mode.

But I do have a capacitor connected between pins 7 and 8 (VCC and GND) and also a capacitor between reset line and +5V. Should not this take care of the voltage drops?

Please...if anybody can give me some tips and directions, it would be great since I am beginning to run out of more ideas to make this thing work.

Thanks.

Rmore

July 06, 2012
by Rick_S
Rick_S's Avatar

Not quite sure why you started another thread instead of continuing on with the one you had going, but I digress.

First, did you do what I said in the other post when I said:

"I can't speak directly for the AVRISP, but many programmers provide voltage to the circuit and don't need an external source. Try disconnecting the battery and see if your programmer does. Programmer wiring sounds correct from what I can see. "

Second, it is 100% normal behavior for the reset line and other programming lines to temporarily drop low. This is how the programmer communicates with the micro. It sounds as if your programmer is trying to communicate.

Also, what software on your pc are you using to "program" your microcontroller? What error messages are you getting? What is the EXACT part number of your microcontroller including any suffixes?

Sometimes screenshots of your errors can help in the diagnosis.

Rick

July 06, 2012
by rmore
rmore's Avatar

Rick,

The AVRISP mkII needs voltage from the target - so the battery has to be connected.

Anyways, problem solved.

Its kind of embarrassing! I got wires from Radioshack since my wires from the Nerdkit got over. I bought the thinnest available wires but turns out that they are thicker than the ones provided by Nerdkit (although they say 22AWG, the metal inside is copper-color and thicker....whereas the wires from Nerdkit also are 22AWG but the metal is thinner and silver-colored). I may be wrong since I do not have much knowledge in this! Anyways the point is, after repeatedly using the thicker wires on my poor breadboard, the metal backing on it got pushed away and i found out that the SCK line was open since the wire did not make contact with the breadboard metal.

I also made sure I had a 10k ohm pull up resistor on the reset line and a 0.1uF cap on VCC and GND.

Thankfully everything is working fine and I can now proceed with further tinkerings.

By the way I have ordered new wire from Nerdkits since Radioshack doesnt seem to have the thin silver metaled wires...and perhaps I will have to buy a new breadboard and play safe with it.

Thanks a lot for your help.

Rmore

July 07, 2012
by Rick_S
Rick_S's Avatar

Glad you got it going. Thumbs Up

The reason I brought up power is because the programmer I use can go either way. It can be powered by the target or it can provide the power to the target.

As for the wire, 22AWG wire whether the tin plated version provided by Nerdkits or the plain copper version you got at Radio Shack, it should be the same diameter. If it isn't, one of the two isn't 22AWG.

Bad connections can sometimes be a pain to track down... No need to be embarrassed, it happens to all of us from time to time and it's very frustrating when it does. Mad

Rick

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