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Old 30 September 2017, 15:31   #1
Bprepared
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Join Date: Feb 2017
Location: Cirencester, UK
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and another CD32 Riser!

Well this one is a little left field, so I want to take a moment to explain the reasoning and theory behind it.

The FB-32 was conceived the day after Stedy decided to permanently shelf the Hermes project.
I first read his blog shortly after I brought my CD32 out of its 20 year slumber in a garaged crate 6 months ago, and was excited at the thought of being able to acquire something resembling a SX-32...I really wanted one of these when Amiga's were my main stay computer systems back in the day.
Needless to say I was gutted at the news of the projects death, but with the birth of the TF328, the major functionality had been met, and I completely understand the "too many spinning plates" analogy, as being a design engineer myself I have so many projects of different disciplines on the go.
That said, I still wanted to squeeze as much functionality out of the sadly mis-understood console, and although Kippers Riser would enable me to use the TF328, and give me RGB/Keyboard, I wanted something that would allow me to eventually have a floppy interface, serial and parallel ports, a clockport etc.
The trouble was that I didn't (and still don't really yet) have the VHDL/Verilog skills to be able to implement the necessary logic, and with the limited real-estate on a riser, standard logic chips are not really an option unless I wanted something that was the size of the CD32 Debug board.
So I pondered how I would go about learning the language (I have previous in C, C++ and 68K Assembler from my days in Uni where I studied Avionic Systems Engineering), and figured that if I took a leaf out of Stephen's (aka Plasmab, aka TerribleFire) book and only bite off small chunks at a time I would eventually get there.
But I wanted a Riser now, so I started thinking about how to do a breakout such that I could develop my skills while still having a usable board. The result was the FireBird FB-32R below:



Named as such for several reasons; first that is born from the ashes of Hermes...Stedy I hope you don't mind, second is that provides for the rising of a TerribleFire, and finally my avatar logo (which is also associated with my company) was Phoenix inspired...but that's another story.

Fundamentally, it starts as a passive board, with 2off 2x40 2mm Female Pin Headers giving 160 of the 182 signals from the CD32's edge connector. I choose to pull as many signals as I could, but drop those that were probably never going to be used i.e. the _EXT Video signals associated with the FMV module, and a few VCC/GNDS.
The female headers were selected as they allowed me to piggy back a second board on the back which will contain the magic, while not exposing pins to potential shorting. They can take 1A of current nicely, and the height of 2mm header male and female together are the same as standard PCB stand offs, so I don't have to rely on the connectors taking all the mechanical strain and abuse loads from plugging/unplugging cables, and I can develop different riser configurations with only needing to solder 160 through-hole pins (worst case) instead of 364!

The FB-32R was sent to the Dirty PCBs earlier this week for production, but like Kipper said yesterday China has a week long holiday starting Sunday so I don't expect to have the prototype until the end of October at least.

I have 3 planned modules at the moment, the first of which is in KiCAD cooking and will be sent to Dirty for when they get back from holiday:

FB-32G - Basic gamer module
- 23 pin Std Amiga RGB port with Genlock
- 15 pin Minimig RGB port as per Stedy's design published in the main CD32 Expansion thread
- PS/2 Keyboard port
- Basic RS232 non-handshaking null modem port - Thanks for the suggestion 'kolla'

Note:- This is just to get the ball rolling beyond being a passive riser, while also adding a feature that I don't think has actually made it onto a anyone else's riser yet.

FB-32G+ - Full gamer module
- Everything from the 'G'
- Floppy Drive port - based on the venerable Aminet design from Bruce Abbott
- Clockport

Note:- this module will be my first HDL project so I need to manage expectations on this. I'm personally not expecting to have it running until at least Christmas this year, but I may need to revise this timeline based on the time I can actually spend learning HDL.

FB-32PRO - Final planned module
- All of the above, although I may drop one of the RGB ports if I run out of real estate.
- Clockport based Full Parallel and Serial
- Built-in RTC
- USB Mass Storage device port - based on Ferix's design

Other features may be added if space allows, that said I have other ideas on how to combat that problem.

Finally, I will be making everything open source, that is once I have verified each development, so the day the FB-32R is built I will post the KiCAD schematic and board files on Github, and anyone is welcome to develop their own modules as well in the meantime. Attached is the SCD I've whipped up for the critical dimensions.

Oh..and thanks should also go to 'solidcore' (Chris) for egging me on to get this finished and published.

OK, I've said my piece, let the trolling commence.
Attached Files
File Type: pdf FB-32 Module Specs.pdf (63.1 KB, 189 views)

Last edited by Bprepared; 01 October 2017 at 13:48.
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