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Electronics => Electronics => Topic started by: Weird Fishes on August 14, 2009, 01:44:39 PM

Title: Programming a custom Augmented MCU
Post by: Weird Fishes on August 14, 2009, 01:44:39 PM

I built my own augmented mcu and finally got the programming header connected and built the USBTinyISP. The ISP can connect to my Baby-O just fine, so I'm sure it's OK. It doesn't connect to my MCU (an Atmega328, BTW) though. I'm pretty sure the connections are good and the header is connected properly. I've attached the schematic I used to build it.

I'm using AVRDude on mac. The message I get is the infamous "initialization failed, rc=-1".
Is that circuit OK? I'm mostly concerned with the reset pin. I originally had a switch there, but it was put in sideways and was always connected to ground. I also added a capacitor from reset to GND, but that's not on the schematic (and it should be, so sorry :)).

Any help is greatly appreciated. Also any other help besides the schematic... Like other things I might be forgetting. I've run through all the things at the USBTiny site with no luck. My crystal is oscillating fine (gotta love the oscilloscope =P). I've run out of ideas.

Title: Re: Programming a custom Augmented MCU
Post by: Weird Fishes on August 14, 2009, 02:07:08 PM

Quote from: Weird Fishes on August 14, 2009, 01:44:39 PM

I'm pretty sure the connections are good and the header is connected properly.

You can cancel that. MOSI was shorted to VCC. Luckily nothing was broken.

Title: Re: Programming a custom Augmented MCU
Post by: SmAsH on August 15, 2009, 04:06:40 AM

heh, always check and double check connections with a multimeter ;)

Title: Re: Programming a custom Augmented MCU
Post by: Weird Fishes on August 15, 2009, 09:59:25 AM

How do you think I fixed it? :P

Title: Re: Programming a custom Augmented MCU
Post by: SmAsH on August 15, 2009, 04:37:32 PM

heh, it shows!

Title: Re: Programming a custom Augmented MCU
Post by: Weird Fishes on August 15, 2009, 04:38:38 PM

what shows?

Title: Re: Programming a custom Augmented MCU
Post by: SmAsH on August 15, 2009, 04:40:00 PM

that you should always use a multimeter if a problem occurs.

Title: Re: Programming a custom Augmented MCU
Post by: Weird Fishes on August 15, 2009, 06:02:51 PM

Well duh. ;D

I figured I must've done something wrong, so I checked a bunch of stuff with the multimeter. I also checked a bunch of stuff with my oscilloscope. How I missed the short, I don't know. It was quite a strange short, I'm still not quite sure how I even fixed it. haha :-\

Title: Re: Programming a custom Augmented MCU
Post by: galannthegreat on August 16, 2009, 08:42:44 PM

Good on ya for finding it before the circuit was wrecked... Just a little advice, sometimes you can mistake solder bridges for flux trails (as being in this case flux wouldn't be a problem), so I'd recommend you spray some electronic cleaner/WD-40 (wipe off after) on so it can get rid of the excess flux, that is if you are having this issue. It works for me! ;D