Programming socket board - required parts?

I seem to have accumulated a number of 168/328 DIPS. Some, but by no means all, have bootloaders. I have a USBtinyISP which I have in the past used to burn bootloaders and/or sketches.

So far, so good. I now want to put together a board (not a shield) with a ZIF socket so I can program chips easily. All of my stuff uses either a crystal+caps or resonator at 16MHz.

Aside from connecting the ISP pins, what else needs to be on the board (assuming I'm powering the programmer from the USB port).

I think I need to provide a clock, but is that correct, and what else have I forgotten? ;D

Also, I'm thinking of putting two ISP connectors, connected to a 40 PIN ZIF, so that VCC,GND,XTAL1,XTAL2 are consistent (obviously, this means plugging in the 28 pin devices offset from the top) so that I can use it for 168/328 and 1284P devices. Is this feasible? That seems to make more sense to me than coming up with some kind of fancy way of switching all the signals.

The alternative is to build separate sockets, but somehow that just feels wrong :-/ Any advice would be welcome.

This is one I built some time ago:-

what else have I forgotten

A 10K pull up on the reset line. A 0.1uF on the Aref line. Connect both Vcc lines to + and both ground lines to -.

Of course, (slaps forehead). I should have remembered about the pullup - I'm having an "ash blonde" moment - caused by having too much grey hair...

Thanks, Mike.

... and of course, that requirement means it would be much simpler to build two boards, one for 28 pin and one for 40 pin. At least both families (168/328 and 644/1284) are pin compatible. I should be grateful for that, I suppose.

Here is one I threw together pretty quickly that works with the Bus Pirate. Shouldn't have any problem working with the the USBTinyISP.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1275535990 http://www.jkdevices.com/buspirate/

hey guys i have built a prototype on stripboard pcb and finally decided to make it a shield

http://batchpcb.com/index.php/Products/34990

essentially it's a shield 1. pull out your existing DIP from the arduino board 2. the shield has male machine pins into the dip socket of the arduino 3. there is a ZIF socket slightly offset but connected to the male machine pins 4. there is extra area for prototyping 5. all pins are connected to the arduino pins

this in effect would be the same as building an arduino dl kit but putting a zif instead of a dil socket where the atmega goes

Jeff K's is closest to what I want to do, as I don't want a "shield" style one.

It doesn't look like it would be beyond even my soldering skills and eyesight (especially as I have a USB microscope/camera, which makes even a 0.5mm iron tip look vast), so I can feel a stripboard build coming on.

I think I've found a potential gap in what is admittedly a small market; I can buy an etch-resist pen. Now if only I could buy an 'etch' pen, I could do away with my spot-face cutter and other sharp implements...

Cotton-bud and etching fluid, anyone.... :D

Jeff K's is closest to what I want to do, as I don't want a "shield" style one.

fair enough! the one i built was so that i can rapidly pop the shield on top, throw in an atmega into the zif, updload, lather rinse repeat

That's what I have in mind, but without the Arduino board underneath :) Drop a chip in, throw the ZIF switch, plug the USB in, download. unplug USB, remove chip, repeat as necessary. I assume the USBTinyISP doesn't "switch off" all the lines when it isn't in use, so the VCC/GND stays connected, or I wouldn't need to unplug it. In these cases I'd probably be running a command line avrdude rather than using the IDE (Windows platform - I'm too mean to buy a Mac).

You could just add a switch to your board that would just cut the 5v to the socket so you wouldn't have to keep unplugging things. But you might even be able to add a transistor that would automatically switch it on when programming.

But it looks like the USPTinyISP should have a jumper to remove power anyways... http://www.ladyada.net/make/usbtinyisp/use.html

I guess that depends on where you got it and how you built it tho.

It is an original ladyada kit. Bought it from oomlout. It does indeed have a power jumper, but a switch on the board would be a good idea, so I'll put on one. I'm certain to have some kicking around in one of my "parts boxes".

The one on the USBTinyISP is a bit fiddly to remove, with my fat fingers and dodgy sight, so this is a much better solution, and will save wear and tear on the USB connection :)