1284P top mount card

Solarbotics ardweeny style.

Great!
Just plug it into your breadboard, all necessary support components already there.
Also using this makes a PCB design less complicated as parts are on top.
Make this card plug into a socket that is permanently soldered to the 1284, therefore it is removable.
Thanks.

Yes, I could see that using this on the chip
http://www.dipmicro.com/store/HDR40X1FM
maybe even a socket?
http://www.dipmicro.com/store/ICS640
http://www.dipmicro.com/store/ICS640M

and this on the board
http://www.dipmicro.com/store/HDR40X1MM
(will be in stock again)

If only 40 and 28pin WireWrap sockets weren't so expensive, it would be pretty easy to make some really nice modules.

http://www.king-cart.com/phoenixent/product=SOCKETS+WIRE+WRAP+DIP+%26+SIP/exact_match=exact

$1.77 doesn't seem bad for 40-pin.

Some modifications. Bottom view.
Maybe room for led and reset button.

Can you share the SCH and BRD files?

Looks like thru hole parts - I was trying to keep all SMD components, big 1206 size for easy soldering, so there would be no thru holes & let the board sit flat on the 1284P chip.
Allowed the FTDI header support right angle SMD, or thru hole for increased durability.
Can add LED & reset button, plenty of room.

Updated idea.
Now we need a young man to make them. CROSSROADS

EDIT:
My FTDI supplies +5V on pin 3 of the header. If the 1284Weeny is being powered by an external supply these will cause a conflict.
Should there be a option to disconnect the FTDI +5 ?
Drawings updated with jumper.

Made a DIY PCB
See image, works great.

Niiiiiice! So do it up in eagle and order a batch, put 'em up for sale here. Or are you waiting for me to do that 8)

I did it in WinQcad an old defunct PCB package.
I'm too old.
Decided to move the traces to top of the board for ease of soldering.
SS with 1 jumper

Would be a nice addition to your product line.

Ok, once I can tear myself away from the Olympics. Could be a couple days more so I can add some labels too.

Just discovered a upload will not work if the 1284 with top card is plugged into a bread board.
Probably a crystal load capacitor issue.
I’ll change the two 22pf caps tomorrow to something smaller and see if it works.

Works 100% if not plugged into the breadboard.

There was a lengthy discussion about fuse settings and misbehaving 1284s. Your symptoms seem similar. I believe the conclusion was that Full Swing Oscillator solved the problem.

Or a gnd plane is needed around/under the xtal. Maybe remove traces connecting xtsl leads down to vreadbosrd as well.

Maybe remove traces connecting xtsl leads down to vreadbosrd as well.

You have the solution!
Bending out the two pins at 90 degrees (so they do not plug into the breadboard) fixes the situation.
Did not try a ground plane, it may work too.

Just a note, only pins 8,9,10,11,12,13,14,15,30,31 and 32 are need for the daughter card so may be don’t’ use all the remaining pins?
However if you use all the pins you then have something to hang your logic analyzer on.

There was a lengthy discussion about fuse settings and misbehaving 1284s. Your symptoms seem similar. I believe the conclusion was that Full Swing Oscillator solved the problem.

@Coding Badly
As soon as I figure out how to change the the fuse to 0xF7 I'll report back.

That’s just a setting in boards.txt, then re-burn bootloader.

only pins 8,9,10,11,12,13,14,15,30,31 and 32 are need for the daughter card

That doesn’t seem like 32 IO and power, Gnd to me. Not sure what you are saying.

I was just saying pins 1,2,3,4,5,6,7, 16,17,18,19,20,21,22,23,24,25,26,27,28,29, 33,32,34,35,36,37,38,39,40 are not used for anything on this top card and don't have to be taken there.
The 1284 pins them selves would plug into a breadboard or mother board so we can access all the signals there.

But I like that they are on the top card ( daughter board ) as I can clip my saleae probe to them.

"That's just a setting in boards.txt, then re-burn bootloader."
Thank you.