Tag Archive | Atmel

x0x, MCU problems

I have no idea what happened, but when I started experimenting with fuse settings after diagnosing the MCU running at wrong clock speed, the chip went dead. The programmer software (Ponyprog) just constantly reported the chip as “unknown device” despite detecting it ok previously. My bet is on a voltage spike or such, though ESD can be counted out right from the start.

Anyway, a replacement part arrived last week, after which I was able to complete mapping the fuse settings. Here’s the combination that works on my setup:

  • bod0level = 0
  • bod1level = 0
  • bod2level = 1
  • ckdiv8 = 1
  • sut0 = 0
  • sut1 = 0
  • cksel0 = 1
  • cksel1 = 1
  • cksel2 = 1
  • cksel3 = 1
  • bootsz0 = 0
  • bootsz1 = 0
  • ocden = 1
  • wdton = 1
  • eesave = 1
  • ckout = 1
  • m161c = 1

Not that I tested every combination, but this was rather the first set with which the x0x powered up seemingly normal. Sequencer running ok, buttons responsive and all that.

Getting the MCU running revealed plenty of defunct leds on my custom keyboard though. The ones soldered directly to the board work fine, so it’s not difficult to gues that the problem lies somewhere with my custom cabling! No need to guess what I’ll be working on next..

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AVR Synth, putting it together

Time to bag this one up then! As I anticipated, the clear plexi glass covers about to be binned were just the thing for the casing of my AVR Synth. From the company perspective (where I work, that is), the problem with these was that the plexi glasses have been stored for quite some years, so the thin plastic film used to protect the plexi from scratches had dried up and was no longer anywhere near easy to remove. In practice, removal attempts resulted in a scratched and/or cracked plexi. Now, if you’re trying to sell a new product, scratches or cracks on the surface simply won’t do.. Me on the other hand I’m not selling a new product, so free heaps plexi are always free heaps of plexi ;)

So.. Using two of these covers, I was able to make the upper and lower halves for the casing with minimal effort. To assemble the halves together, I decided to make a bunch of L-shaped brackets from aluminium and thread them for M4 screws. I’ll also decided to mount the potentiometers and switches directly to the plexi, as this will allow me to hide all their mounting screws/nuts behind the front panel. This here is the lower half with brackets etc. mounted..:

AVR Synth, lower half of the casing

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AVR Synth, electronics

Came across this fancy little project by Jarek Ziembicki / Elby Designs during this summer and figured it’d make a neat one to test building a rack module. Compared to my earlier projects, I figured I’d also first (for once) gather all the parts before starting assembly. That is, as the project isn’t a big one it’s best off completed within a few sessions.

So today, I completed the electronics assembly. Not much to the board as the part count is quite low, sorting out the matched resistors for the D/A converter was maybe the most time-consuming bit of the electronics bit. I’m even too lazy to snap a photo out of the plain board so I’ll just borrow the one from Elby Designs site ;)

AVR Synth, equipped circuit board

Differences being, my board has the DC regulator heat sink installed horizontal (vertical installation wouldn’t fit inside a 1U rack case) and for the two-pin cables I use Hirose cable crimps/connectors instead of screwdriver terminals. Next up, the mechanical assembly. Looks like there are some clear plexi covers waiting to be binned at work, reckon they could be used for the casing..