Computing > Vintage Computing

San Bergmans NanoSBC 6802

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granzeier:
By the way, I ordered 10 boards from Seeed Studios and have six left. If anyone would like one, I can pop it into a small letter envelope and send it first-class mail. Included will be my assembly notes and the Bill of Materials (BOM.) It will cost me $0.75 for anywhere in the Continental US, but more for out of the US. So, only people here in the US, please.

If anyone else would like some boards to play with, https://www.seeedstudio.com/Motorola-MC6802-nano-Single-Board-Computer-(SBC)-g-1013152. There are a couple tiny differences between this board and San's, let me know and I can email you my assembly notes and the BOM (the board designer did not match up the component designations with the schematic

Phil_G:
Sorry I didnt realise that in the opening post I didnt give the link to the PCB on Seeed, yes thats the same board as in the video above (I also have a few spares!):
Sans PCB
When time permits I might remake the display and keypad on a proper PCB to match Sans 6802 board, that would neaten up the project, veroboard always looks 'temporary' to me!
I do like the 6800/02, back in the day I found it to be one of the easiest for hand-coding - the monitors 'relative jump calculator' helps.   As a background project I'm looking at a GAL as a single-chip decoder for rom, ram and io on Sans board, but I keep thinking the beauty of the original project is in its simplicity.  Its not original of course, its the 'minimal system' documented by Motorola :-)
Did you notice that San has the silkscreen annotation for the reset button is 90° out?
Cheers
Phil


granzeier:

--- Quote from: Phil_G on June 01, 2021, 09:25:52 am ---...Did you notice that San has the silkscreen annotation for the reset button is 90° out?
Cheers
Phil

--- End quote ---
Yeah, actually that Seeed board was not designed by San, it was designed by another guy. Unfortunately, he did not put any component values on his silk screen. I traced out all of the components, and came up with a BOM, which I can email (along with some other assembly notes) to anyone who would like.
Also, I did not notice the reset button placement "error" myself (but it is mentioned on the Seeed Studio page.) I use a different 2-pin push-button (found them really cheap and bought several thousand.) All I needed to do was trace out the pins to the reset, and plug in my push-button - we shall see how well I did with that.  :P

Phil_G:
Thanks, I didnt know who did the boards so assumed it was San, the 'Barta' heading did make me wonder   :)
The ancillary components are only pull-ups and decoupling, nothing is critical, I used 4k7 throughout and 100n.
I used a cheap RS 4mhz crystal with 20pf either side. For ~A15 I found a BS170 in the junk drawer but I suspect any small fast N-channel EM would do.  I do like EEPROMs instead of EPROM, so convenient  :-+
If you fancy doing the system above, TIL311s  or DIS1417s are readily available on ebay for not much, and the keypad was only a couple of quid.  Fun though, isnt it?   :-+
Cheers
Phil

granzeier:

--- Quote from: Phil_G on June 01, 2021, 08:14:47 pm ---...If you fancy doing the system above, TIL311s  or DIS1417s are readily available on ebay for not much, and the keypad was only a couple of quid.  Fun though, isnt it?   :-+
Cheers
Phil

--- End quote ---
Yep, fun!  ;D
I do plan on making something like yours, but the prices that I've seen for those displays are above what I'm willing to pay - especially for something that just takes binary and converts to hex. I've been doing that conversion for over 45 years, and have gotten pretty good at it. 8)  So, I'll just use discrete LEDs in my version. Also, I sell hex keypads in my store, so I'll just use one of those.

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