Profile cover photo
Profile photo
Propeddle
44 followers -
Software-defined 6502 Computer
Software-defined 6502 Computer

44 followers
About
Propeddle's posts

Post has shared content
A great article from +The Western Design Center, Inc. arguing the case for learning (and teaching) Assembly language to software engineers. It describes pretty much exactly why I'm working on projects like Propeddle [1] and L-Star [2]!

"So, how did [software engineers in the days of 5MHz 8088 machines] achieve reasonable performance on such low-end processors? The answer is not a secret–they understood how the underlying hardware operated and they wrote their code accordingly. That same knowledge, of the underlying hardware, is the key to writing efficient software today."

[1] http://www.propeddle.com
[2] https://hackaday.io/project/3620

Post has shared content
Propeddle was featured on Hackaday today!
When it comes to building retrocomputers, there are two schools of thought. The first is emulation, that allows for greater compatibility and ease of use, and much easier to find parts. The second requires real, vintage hardware with all the bugs and…

Post has shared content
A short video demonstrating Propeddle running Ken Wessen's Krusader ROM on a Propeddle connected to a TV.

Post has attachment
Over the past few weeks I’ve been spending some time implementing a module called PropeddleTerm, which is a partial emulation of the Apple-1 keyboard and video interface. Today I finally fixed the last bugs in that module, and created an Apple-1 emulator…

Post has shared content
I got the parts from Mouser to do a test build of Propeddle; call it a "dress rehearsal" before going into production, if you will. I'm very happy with the result. Check out the pictures of the first ever Propeddle living on a single circuit board!

(See individual pictures for more comments)

More information at http://www.propeddle.com
PhotoPhotoPhotoPhoto
Propeddle Test Build
4 Photos - View album

Post has shared content
Propeddle is working at 1MHz, and that's the wire wrap version with no decoupling capacitors!
PhotoPhotoPhotoPhoto
Propeddle Wire wrap SUCCESS!
4 Photos - View album

Post has shared content
That's a wrap...
(Not it's not -- I just wanted to say that).
PhotoPhotoPhotoPhotoPhoto
Propeddle Wire wrap FAIL...
8 Photos - View album

Post has attachment
This is what Propeddle Rev. 10 will look like.
Photo

Post has attachment

Post has attachment
Achievement unlocked: Propeddle schematics converted to Kicad and uploaded to Github

I've been working on my Propeddle project (http://www.propeddle.com) for about three years now (on and off -- mostly off), and one of the things that's been on the to-do list for a while is to move the schematic from the free "Light" hobby version of Eagle to Kicad or some other electronic design program that will let me make the PCB bigger, and won't take me to court for selling my design as a kit, and won't cost me so much that I have to double the price for the kit to make up for the expense.

I've tried the conversion before and it failed every time, and I couldn't figure out why. I even tried other software besides Kicad (such as DesignSpark, which I really liked by the way) to see how much trouble it would be to just start over.

There's a script online called eagle2kicad.ulp which you can install in Eagle to convert schematics to Kicad format. Apparently it's not perfect so I'll have to make sure that everything is correct in the converted file, but all it did for me before, was generate a file that had a lot of text in it that was apparently correct, but showed up as a blank schematic in EESchema.

For some reason I decided to try it again today and it still wasn't working, but I noticed that there was a small blue line next to the border. When I zoomed out, I saw a giant version of my schematic. So I did some googling and found out there's a bug in the .ulp file which makes it get the scaling all wrong, by a factor of 32 to be exact. Strange that CircuitBee (who publishes the version of the script that's on top of the Google results) hasn't fixed it. It really is a small bug.

Anyway, the schematic is far from perfect and the script doesn't convert the PCB layout (only the schematic), but that's not a big deal, I want to make a new PCB anyway: the current schematic is based on the fact that the user has a Propeller Platform motherboard and a modified Propeller Platform audio/video/keyboard shield, and my goal is to produce a PCB that has everything on there, including one or two improvements from what it is now. At least now I have the converted schematic, it will save me a lot of work getting started on that.

Now let's find some Kicad tutorials :-)

https://github.com/jacgoudsmit/Propeddle/tree/master/Hardware/Kicad
Wait while more posts are being loaded