DIP SMD "programmer fittings"

[Thunderchild]

it just occured (to my over active mind ) that it would be very handy not only to have pic projects built for ISP bu also the header for the programmer connection is gong to use axtra space, is there a "connector / adapter" that allows you to place it onto the chip itself and program it (having done the usual circuit considerations for ISP)

 

[Mickster]

Something like a SOIC test clip, for instance?
You'd also require different clips for PICs with different pin numbers/pinouts, unless you stuck with one device.
Another method is to use contact pads and pogo-pins but then you may as well just use a header, unless you are mass-producing and want to save the expense of extra holes/headers.

 

[Thunderchild]

yea something like a test clip, what i thought was if a "fitting" is available I can wire the appropriate pins to the programmer as per the device, mainly used for updating programs on prototypes save keep yanking the chip out every time and making it possible to use SMD (SOIC) parts more easily

 

[3v0]

Unless you want to do in circuit debug use a boot loader.

 

[Thunderchild]

err how would a boot loader (and I'm not entirely sure what that is) help me reprogram stuff on the board ?

 

[Mickster]

PICkit2 has a bootloader.....the device is able to be updated via USB, so a bootloader program still needs an interface to the outside world.

Booting - Wikipedia, the free encyclopedia

If you aren't wishing to go this route, maybe the test clip idea could work for you and since you mention SOIC, have a peek at these:
**broken link removed**

 

[Thunderchild]

I see, well the boatloader is obviously not what I'm after, those probes look nice thanks

 

[be80be]

Thay make a device that looks some what like a close pin it clips over the chip
I have them for dip chips haven't used much smps

 

[Thunderchild]

where did you get them ? I'm thinking of both DIP and SMD/SOIC, really if I can implement ISP using a "clamp" then there is no reason to not work with SMD chips and have a little more room, but I think soldering quality may have to be good and I'm probably not the best as I've only done one ship, but still DIP is still a variable option

 

[Mickster]

where did you get them ? I'm thinking of both DIP and SMD/SOIC, really if I can implement ISP using a "clamp" then there is no reason to not work with SMD chips and have a little more room, but I think soldering quality may have to be good and I'm probably not the best as I've only done one ship, but still DIP is still a variable option

There's only one way to get better and that is to practice.

Most of us have a few scrap PCB's knocking around, just in case we need something from them. Take a heat gun, hot air pencil, or whatever you choose and remove a few SMD IC's, clean up the pins & PCB pads, then remount them.

Normally, you can only get better with hands-on experience. The boards are usually scrap......apart from time, what do you have to lose?

 

[Thunderchild]

are you saying that SMD chips can be soldered/desoldered with a heat gun ? I've been planing on using my 12 W iron with a 1mm bit on it for soldering, i think i need to master flux application, where do the "clamps" make contact on the chips ?

 

[be80be]

I got the clips from work I don't no of any one who sales them now but I bet they still sale them
the ones I have fit a 8 pin dip and a 16 pin**broken link removed**

 

[Mickster]

are you saying that SMD chips can be soldered/desoldered with a heat gun ? I've been planing on using my 12 W iron with a 1mm bit on it for soldering, i think i need to master flux application, where do the "clamps" make contact on the chips ?

If you have a scrap board, you can remove SMD IC's by whatever method you choose, as long as the device remains sufficiently intact to be re-used. You can mount some of the fine pitch devices with a suitable tip and a very steady hand, a DIY reflow oven, or by flood-soldering and sucking up the excess with solder-wick.

IIUC, the test clips would make contact with the pins on the devices - anywhere else would be pointless....

 

[Thunderchild]

If I remember rightly the pins on the SOIC come out of the case and then bend down slightly and then straight out, so unless you solder like a monkey and the "clamp" makes contact with the section of the pin that is closest to the case it should be ok ?

 

[edeca]

If you are trying to reprogram your chip easily without having a huge header on the board, a bootloader is one option as 3v0 suggested. The idea is that when the chip is reset the first code that runs is your bootloader. It is responsible for deciding whether to boot into your "real" code or whether to do something else, such as update the "real" code from a serial/USB/whatever. The newer PIC parts are clever enough that they can rewrite their own program memory from within code. This is often seen on things such as home routers, which might wait 10 seconds in the bootloader for a valid connection or for the user to press a button, etc.

If the aim is to seat a clamp over a SMD part (e.g. SOIC) then I'd suggest some sort of hole or notch in the board, one above and one below the chip. You could stagger them or make them such that your special clamp only fits one way and clips into the holes. But all that sounds like overkill.

If there is already connectivity to the outside world on the board as part of the design (e.g. serial or USB) then a bootloader is a fantastic option. If not, why reinvent the wheel by making a one off fancy gadget that nobody else in the world has? Both the Microchip RJ11 or the 10 pin IDC are fairly standard in hobby circuits.

 

[tunedwolf]

I use various test clips for loads of diagnostic work, most of the smd clips and burn-in clamshells I have, were purchased from Emulation Technology.
They have a whole range of different sizes and types available. The smaller SOIC clips they have would be suitable for your general "PIC" stuff.

**broken link removed**


rgds

 

[AtomSoft]

Ok i was reading this but kinda got lost heh... would this be for breadboard or actual in circuit stuff? If breadboard i made some small Adapters for Pickit that are cool ... also have a nice idea for some...

If for in circuit items then its wise just to place SMD pads for the ICSP pins and use POGO Pins to connect to pads (no soldering needed) to reprogram...

Pogo pin - Wikipedia, the free encyclopedia

 

[Thunderchild]

well I'm going to put in headers for now for the pickit2 programmer and I'll probably stick with that for a bit

 

[Oznog]

Sure! SMD can be desoldered with a heat gun!
You'll likely loosen nearby SMD components too, so don't bump the board.

I've done it with the heat gun on bottom and have done it with the heat gun on top. There's something of a danger of burning the board with it on bottom, but little danger of burning components.

Components, even ICs, are not rated for repeated exposure to the high temps of soldering air, esp not the typically inaccurate overexposure used with a heat gun. But, it works. Note that some components like capacitors, IC sockets, sensors, and WIRES may have a plastic coating or body which will be badly melted by the hot air. It's not readily avoidable.

Note that MANY chips have DIP versions already available. You can develop with DIP while putting SMD on the production board. I don't, though. SMD isn't hard to work with. In fact I find popping SMD stuff on and off to be pretty darn easy now.

 

[Thunderchild]

well like you say it is probably easier to play with DIP than SMD for example on breadboards and then use SMD for the actual finished thing, with a header in place for ISP there should be no problem unless I blow the chip but then it's a gonna anyway