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PCBs for 6800 / 6801 / 6802 / 6808

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saipan59:
I hadn't made a non-trivial PCB in a few years, so just recently made these.
There are 3 boards:

1) An MC6800 MPU, with up to 8KB of PROM, 2KB of RAM, and an MC6875 clock generator. Also supports the 6802 and 6808 variants (runs directly from a crystal, no 6875 needed). Includes a 6821 for parallel I/O. Has headers for bus I/O expansion. The 6802 has 128b of internal RAM, so the external RAM chip is optional with that one. In the picture (attached), the upper-left is configured for 6800, the upper-right is for 6802.

2) An MC6801 or 6803 MPU. Other features much like board 1).  The 6801/03 has some I/O pins built-in, so a minimal version doesn't require the 6821. External RAM is also optional. Lower-left in the picture.

3) A "shield" to use with the other 2 boards. It supports a 6850 UART, and a bunch of space to build other circuits. It has the same header layout as 1) and 2), so it can be "stacked" on top if female headers are mounted on the bottom.

All major features are working. The 6800 requires 3 etch cuts, 2 missing pullups, and 3 wire-adds to fix a couple of boo-boos. I messed up a bit because I had never actually built anything for the original 6800.
The 6801 board just needs 2 missing pullups on IRQ and NMI.
The crystals are mounted on the bottom, because they might interfere with the 'shield'.

Not sure what I will actually do with these boards...
Did the layout in the free version of Eagle, boards made by PCBway.com .

I originally wanted to make a single board to do both 1) and 2). But Eagle (free) is limited to 12.4 square inches and 2 layers, and I couldn't quite make the layout work, so instead I made 2 versions of the board, and everything was easy.
I know that others have done similar boards, of course, but I had a lot of fun working on them.

Pete

Phil_G:
Would a really simple monitor be of any interest?  uses a 4x4 pad and two TIL311's, plugs into the 6821.
Has display memory, modify, fill, Goto, Serial Load S19, relative jump offset calculator and a SWI breakpoint handler.
Includes a primitive tic-tac-toe demo.
See 6800 page of https://philg.uk
Skip to 3 minutes:  https://youtu.be/j6D_KIOQbsI?si=YIKug6LLud67eAEF&t=181
Just a friendly offer, it is usable though it might be too simplistic for your needs :)
Cheers
Phil

saipan59:
Thanks Phil!
That monitor looks great! But for me, implementing something myself is where most of the "fun" is. I have a hex keypad and various displays that I'm thinking about...

Meanwhile, attached are my schematics, in case anyone is interested. Includes fixes for known bugs.

Pete

Andy Chee:
I've been looking for something useful to do with the 6803's I have in my junkbox.  Unfortunately I don't have a functional 6821 lying around, so need to make something up with discrete logic.

saipan59:
Building something using the boards I recently made.
A 6803 MPU (with RAM and EEPROM), with two 'shields' stacked on top.
The middle shield has an MC6850 UART, and will soon have an MC6840 timer added.
The top shield has a 9-digit LED display, multiplexed by the software, driven by a CD4511 and 74LS145, plus a transistor to do the decimal point.

In the picture, the display is actually showing "8765.43210" .
The dongle with the ZIF socket is currently being used for the EEPROM, so that I can quickly swap the chip without separating the shield boards.

After adding the MC6840, I think I'll make a basic frequency counter. [I really don't "need" a counter, because I already have five different HP counters... ;-) ].

Pete

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