[dorkbotpdx-blabber] rg matrix backpack mind-wipe

[Matt Waddell]

Dear Dorkbot,

Nevermind...  My laptop parallel port wasn't able to produce enough 
voltage with the 470 ohm resistors in series with the signal pins of the 
programmer.  Removing them seems to have solved my woes.  I just need to 
be extra careful now.

_matt

Matt Waddell wrote:
> Dear Dorkbot,
> 
> Has anyone here tried reprogramming the led matrix backpacks from 
> sparkfun?  Are there any particular hoops that need jumping-through?
> 
> I'm trying my hand at it, with little success, using a parallel (bsd 
> style) reprogramming cable <http://www.bsdhome.com/avrdude/>, and 
> avrdude.  I've triple checked the cable, and from all I can tell, it 
> seems to be constructed correctly--minor deviation is that I use 470 ohm 
> resistors on RESET, MISO, MOSI, and SCK, instead of 1k...
> 
> The power source I've been using has been provided by the 5v out of an 
> Arduino--hooked up to the vcc and gnd SPI pins of the backpack.  The 
> programmer is hooked up to the 10 pin icsp header.
> 
> When I attempt to upload my code, avrdude apparently isn't able to 
> detect the processor:
> 
> me at machine$ avrdude -vvvv -c bsd -E novcc,noreset -p m8 -P /dev/parport0 
> -e -U flash:w:somefirmware.hex
> 
> ...
> avrdude: Calibrating delay loop... calibrated to 449 cycles per us
> ...
> bitbang_cmd(): [ AC 53 00 00 ] [ FF FF FF FF ]
> avrdude: AVR device not responding
> avrdude: initialization failed, rc=-1
>          Double check connections and try again, or use -F to override
>          this check.
> 
> I can see that the backback is being reset by avrdude, but otherwise 
> have no other indication of what's going on...
> 
> Anyway, having never attempted to directly flash AVR devices before, I'm 
> sort of at a loss as to where to begin debugging this problem :-( Should 
> I just break down and get a real programmer, or stick to my guns and try 
> and make this rig work?
> 
> Has anyone tried this, or perhaps have some words of encouragement?
> 
> Thanks,
> _matt
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