Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

What connector to use on target board?

Bob D.

New Member
I just ordered a PicKit4 to use with 18F27Q10. What kind of connector does the target board need to interface with the debugger? (Looks to be a Molex in the picture.) Anyone have a part number and recommended vendor?

Bob D.
 

JimB

Super Moderator
Most Helpful Member
I use RS Components 745-4845 (straight pin) or 479-018 (right angle pin).

I don know how easy it is to order from RS in the USA, but I guess that someone like Mouser will have the same components.

JimB
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I use RS Components 745-4845 (straight pin) or 479-018 (right angle pin).

I don know how easy it is to order from RS in the USA, but I guess that someone like Mouser will have the same components.

JimB

RS are available in the USA, but as you say it's a VERY common part anyway.

I would suggest using 6 pins rather than the minimum 5 needed (so you can't as easily get a PK2/3 on incorrectly, or even 8 pins if you're only goping to use a PK4. Personally I stick to 6 pins regardless of PK2/3 or PK4.

I also have a few simple veroboard adaptors I built - with male and female pins/sockets, as straight and right angle extensions, which come in handy.
 

Pommie

Well-Known Member
Most Helpful Member
On PCBs I use a JST 6 pin connector and on breadboard a straight 0.1" male header.
Here's the lead that the pickit4 comes with and (above) the lead I made with the JST connector.
The bit on the right of the supplied pickit4 lead is my adapter to fit breadboards.
pickit4.png

The JST connector takes up much less room on a PCB but being 1mm pitch, I only use them on premade boards.

Mike.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
On PCBs I use a JST 6 pin connector and on breadboard a straight 0.1" male header.
Here's the lead that the pickit4 comes with and (above) the lead I made with the JST connector.

I don't recall any lead coming with either of my PK4's?.

I like the single red heatshrink on your JST lead - makes life a LOT easier.
 

nsaspook

Well-Known Member
Most Helpful Member
I normally use a longer (for easier programmer connection) height 6 pin straight 0.1" male header for the programmer connection on the boards I make.
PXL_20210725_162627637.jpgPXL_20210725_162657061.jpgPXL_20210725_163053173.jpg
 

rjenkinsgb

Well-Known Member
Most Helpful Member
If you are making multiple PCBs that are likely to only be programmed once, you can just use a row of pads and a rig with sprung test point pins (aka Pogo pins) to connect for programming.

You can fit a pin header in any board used for development work to keep the cable connected for debug, then just omit the connector and use another cable with the spring pins for the rest of the units. You can hold it in place by had for the few seconds it takes to program a device.

I'd stick to the six pads on 0.1" pitch for that capability; any smaller pitch and you may have problems with the spring pins.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Recently I've taken to leaving the pin header out of production boards, and I program the PIC in a ZIF before soldering it in - if we do need to reprogram it in the future, I'll stick a header in then. It saves a few pence and a little bit of time, and it's not likely to get upgraded in the future - more profit selling them a new one :D
 

Visitor

Well-Known Member
If you are making multiple PCBs that are likely to only be programmed once, you can just use a row of pads and a rig with sprung test point pins (aka Pogo pins) to connect for programming.

On my TAP-28 dev boards, I use 6 pin 0.1" headers for ICSP, UART and I2C/SPI connectors with any extra pins having I/O pins connected via solder jumpers. There are all connected with the same power/ground arrangement as the ICSP connector, which I have found to be tolerant of the "oops" of plugging in the header backwards.

For the short period of programming, a header can be inserted in the ICSP location and held at an angle to make good contact if installing a header isn't desired.

A handy trick with a PICkit 2 (call me old fashioned) is to set up a software UART, with the pins corresponding to those used in the PICkit GUI UART tool. Load your code, then switch to the UART tool to monitor code progress without the need to change connections or other hassles.

Using the 6 pin connectors, if I2C or UART isn't used, gives me 4 I/O pins (3 on the ICSP header) that can be used for general I/O with the ability to easily switch functions between connectors if needed.
 

Diver300

Well-Known Member
Most Helpful Member
Recently I've taken to leaving the pin header out of production boards, and I program the PIC in a ZIF before soldering it in - if we do need to reprogram it in the future, I'll stick a header in then. It saves a few pence and a little bit of time, and it's not likely to get upgraded in the future - more profit selling them a new one :D
I program production boards by using the header without soldering. As long as through-plated holes are used and the PICkit2/3 is pushed a bit to the side, it works reliably enough, and the programming software checks that it's worked anyhow, so I can just try again if needed.

I'm using QFP PICs, so a suitable socket would cost a lot.
 

Buk

Active Member
Probably talking out of turn here as I've never done this, but wouldn't one of those push-in edge connectors that allow you to mount a small pcb at right angles -- something like this -- be ideal for making this kind of temporary connection securely without needing to add a header?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Probably talking out of turn here as I've never done this, but wouldn't one of those push-in edge connectors that allow you to mount a small pcb at right angles -- something like this -- be ideal for making this kind of temporary connection securely without needing to add a header?

Any 5 or 6 pin connector could be used - but as the programmers are designed using pin headers, and they are dirt cheap, it makes sense to use them.
 

Buk

Active Member
Any 5 or 6 pin connector could be used - but as the programmers are designed using pin headers, and they are dirt cheap, it makes sense to use them.
Understood. But weren't you one of those that mentioned not adding pins for attaching programmers or test equipment to save space and a few pence?

My idea was to not attach this to the boards, but rather to the test equipment; and only push fit it to each board when needed.

C'est la vie. Just a notion.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Understood. But weren't you one of those that mentioned not adding pins for attaching programmers or test equipment to save space and a few pence?

My idea was to not attach this to the boards, but rather to the test equipment; and only push fit it to each board when needed.

It means you've got to buy a fairly expensive connector to fit to your programmer (only one of course), and also arrange the project in order to get to the socket - something far more difficult than with simple pin headers, and the orientation is fixed. I'm not saving space (as the space is there, ready to add them later), and not concerned about saving a few pence (and pin headers are ridiculously cheap), more a question of saving the time fitting something which is likely to never be used. Obviously for prototypes and development versions I fit them, because you're continually reprogramming those.

I don't think I've ever seen edge connectors used for programming sockets?, no reason you couldn't though of course.
 

Visitor

Well-Known Member
Copper pads and even gold ENG plated pads will only be good for a few insertion cycles into am edge connector. To make a durable edge connection, the fingers require plating with hard gold. Online order forms include an option for gold-plated fingers. Click it and watch the price skyrocket.

Fingers for an edge connector also take up a lot of real estate on a board. "Old style" edge connectors have a pitch of 0.156"; more modern ones have a pitch of 0.1". The fingers are between ⅜ - ½" long but you also must include slots on each side of the fingers to accommodate the connector (i.e., the (group of) fingers must like a tongue sticking out). The overall area required is huge.
 

Buk

Active Member
Copper pads and even gold ENG plated pads will only be good for a few insertion cycles into am edge connector.
Understood, but my understanding of the thread was that that was the application: once, or very occasional connection.

The idea spawned from using (pieces of) recycled expansion board sockets as semi permanant connections between chunks of strip board. (A very long time ago.)
 
Last edited:

Visitor

Well-Known Member
It's hard to appreciate how much area those connectors consume. I designed a piece of test gear used on some mid-70s FAA equipment. In the rack of cards comprising this equipment, one of them had a 56 figure, 0.156 pitch "test connector" that brought out the signals I needed to monitor.

The edge connector to receive fingers is nearly 5½" long and about half an inch wide. Let's say about 2.75 square inches. Contrast that to a dual-row, 0.1" pitch header connector, which requires about 0.85 square inches.

Edge connectors are a pain in the butt to work with as well. The contacts on one side are numbered. Easy enough. The other side is identified by letters. As you might expect, they skip I (eye) and O to prevent confusion with numbers. But as I recall they also skip G (might be confused with 6), L (might be confused with 1) and Q (might be confused the 0). They might be more. I did go over my footprint a number of times when I was creating it to be sure I'd gotten the goofy scheme correct!
 

granddad

Well-Known Member
Rather than group the 5(6) pins together I find its more flexible to split to 2 and 3 wires, and use straight or 90 deg pin board headers.. This is attached to Snap , but ok with PK3 . don't make wires longer than a few cm.
icsp6.jpg
 
Last edited:

Buk

Active Member
The edge connector to receive fingers is nearly 5½" long and about half an inch wide. Let's say about 2.75 square inches. Contrast that to a dual-row, 0.1" pitch header connector, which requires about 0.85 square inches.

Edge connectors are a pain in the butt to work with as well. The contacts on one side are numbered. Easy enough. The other side is identified by letters. As you might expect, they skip I (eye) and O to prevent confusion with numbers. But as I recall they also skip G (might be confused with 6), L (might be confused with 1) and Q (might be confused the 0). They might be more. I did go over my footprint a number of times when I was creating it to be sure I'd gotten the goofy scheme correct!

Okay. I guess I shoulda kept my notion to myself; but you can make anything complicated if you try hard enough.

On the other hand, a few standard 1.27mm pitch tracks, a couple(*) of slots and a sata 7p cable will plug on and off easily and provide a reliable connection.
(*1 slot if you position it at a corner of the board.)
1627340524932.png


Crudely approximated:
1627340577211.png


Cheap (especially if you've a few dozen of these cables lying around in your bits box) and simple; requiring little or no more board space than a pin header.
 
Last edited:

granddad

Well-Known Member
One ICSP connection i came across ( not sure where ) had the 6 pads and holes for male type header pins, in a line but slightly offset to each other , so a pin header just pushed in and made a tight connection ok for a single or occasional program.
 

Latest threads

EE World Online Articles

Loading
Top