... or a story how I suck at choosing proper file
Once upon a time, there was a little pony called Bungholio ...
OK! OK! Wrong story. Let me start it over again.
It all started as a fun project. My fellow group member Johny of Lamers asked me if I could make a hardware replacement for his fried SID 8580. He sent me a link to a website with the an awesome project - SwinSID - It was created by Swinkels (Cheers mate!).
Challange accepted !
Home made PCBs
I've started with one of the early versions of SwinSID, more precisely SwinSID SE.
I chose it because it required easy to solder THT components and
it had simplified, one-sided version of PCB.
It was supposed to be totally home made project so I've decided to go with toner-transfer method .... like in '90s :D
First, step required printing layout in a proper size on a paper coated with a mysterious substance.
protip time : This special paper can be found in nearly all homes nowadays, most probably near a toilet throne, so the king can read while "ruling". It is simply a paper from color magazines - the thinner, the better. All you have to do is to cut few pages out and print on it a PCB board layout with a Laser printer.
Next, you have two options. Either go with an iron like in the '90s .... or buy a cheap laminator and hack it to suit your needs. In my case, it was, of course laminator. The hack relied on removing overheating protection and changing few resistors so a laminator could run at higher temperatures. Also cutting out unnecessary parts of plastic case might be handy for larger PCBs
Now armed with a "pro" tool, I could proceed with toner-transfer by simply pushing a blank PCB with a taped on printout into laminator (HINT: use Kapton tape). Just a few passes are needed to transfer toner to PCB. Then I put it into the jar filled with water and after few minutes, I was able to slowly tear soaked paper off. I was ready to etch my PCB. For etching I use Sodium Persulfate - works like a charm.
Here is a result.
Finally, I could solder on some parts.
Here is a photo of nearly complete PCBs.
And here completed PCB with all components populated
Having done that, I've started to burn firmware on an AVRs - in this case, ATmega8515.
Here is a quick hack that I've created for this purpose
Programming is done via USBasp dongle
However, instead of proper SID tune, I was getting squeaking sounds.
At first, I've thought that I've burned wrong fuse bits - nope.
Later, that maybe wrong components - nope again.
I've checked everything 10 times. Also, Swinkels suggested that squeaking might be caused by using wrong DAC so I've ordered new DACs - TDA1543 (not TDA1543A) - still nope.
In the end, It turned out that I was using wrong firmware file all the time....
But I finally got it working ! YAY !
So yeah , that all worked fine and a project was really fun but that is not the end of story yet :>
Going more "PRO"
SwinSID SE is very nice but SwinSID NANO is nicer !
Unfortunately, NANO is a bit harder but still doable if you know some tricks.
Nicolas Welte of x1541.de did a great job and scaled down the original SwinSID project to a SID chip size. I've contacted Nicolas and he gave me a green light with using his board layout.
Thing is that this layout had to be machined on professional CNC tools.
I only have small, home made PCB router which is for prototyping purposes and has some limitations. (it will be covered in another post)
Sending projects to production requires modifications according to manufacturers guidelines , so I had to apply few changes.
That wasn't too hard and after several days, I received a package with nice and clean PCBs. Big thanks to Willy of Lamers for hints about PCB manufacturers.
ZOMG ! some soldering skillz needed
First things first, in this case it means soldering MEGA88PA chip on a PCB.
It might look hard to do with simple soldering iron but in fact, it is quite easy if you have thin solder, good flux, soldering wick and steady hand ;)
Here are few PCBa with chips already populated
Using cheap USB microscope turned out to be very helpful for doing the proper inspection afterwards.
This time, I've double-checked if I have proper file :D
As you can see there are 6 small vias which are used to burn firmware to freshly soldered on MEGA88PA.
This actually required creating an awesome piece of engineering with a wicked name - The Connector.
It was made out of desoldered SATA port, few wires, a bit of epoxy resin, some bee wings, and zombie poo.
It looks like this:
Let the burning begin !
BOOM and it worked out of a box .... to my surprise
Again, not so hard after all but I definitely do not recommend soldering it after few heavy shots. Unfortunately, it turns on specific video effect called - Motion Blur and it lasts till next morning, so be careful ;>
Components that have to be soldered on are simply five SMD resistors , one capacitor, pins and a bulky clock generator which additionally serves as a radiator to MEGA88 chip.
This is how it looks in its final form.
I've made quite a few of these and will be most probably selling it.
No worries, I'll create a link to a store on my main page soon.
Finally here is how it works ... and yeah enjoy this TekknoChipTune ;)