20240714 New Test Programming Clips

In the beginning, during the prototyping stages, I tend to rely on the prototyping breadboards a lot. These breadboards are essential because they would be the basis on how the actual PCB would be designed from.

1. Translating the circuit onto the breadboard.

When I draw up a circuit on paper, it was fun. To make it work, I would need to test my circuit. And there are two methods, each with their Pros and Cons. By choosing the breadboard route, I would be able to modify the circuit as demand changes but there are some compromises. Such would be plugging-in actual through-hole components such as resistors, transistors, etc. and with a lot of wiring going through them. This was the part I hate as I need to pull strands of wires, measure them and then strip off each ends so they could be inserted into the breadboards. Occasionally, I would be using a pair or tweezers and as luck would have it, the very wire that needs inserting would be between other wires or that other components are in the way.

2. Programming

To me, this is the fun part. Depending on how the microcontroller’s ports are used, sometimes during programming, some LEDs would flicker as they are electrically connected. During the prototyping stage, programming the microcontroller is just a simple task of removing it from its socket in the prototype breadboard and inserting it onto the programmer. Once it’s programming has been updated, it would go back to the breadboard for more testing.

But after some time, the process can really wear you down. Moving the chip around between the sockets tend to wear out it’s leads and weakens them. Then programming errors would creep in and you will start to spend more time troubleshooting from the connectors to the chip to the programmer.

ICSP

Programming the microcontroller while the circuit is still being prototyped is OK. But what happens when the PCB has been finalised and the microcontroller has been soldered onto the board? De-soldering, re-programming and soldering the chip for every software change will wear out both the board and the chip itself. This is where ICSP (In-circuit Programming) comes in.

In a nutshell, ISCP, is programming the microcontroller while it is soldered onto the PCB. And for me, just as long as the 5 programming pins are connected, it works. I would start by soldering the wires onto the chip and the other end would be a makeshift socket that goes to the programmer. Unfortunately this idea would not hold if the circuit is being moved about where the wires would end up being pulled.

The next best thing would be to solder a USB socket and make my own ICSP connectors. But it also made me think. I can only do this if the circuit board has space for it and more importantly, even if I did it, the concept would be a waste of money as it would only be used once. For a prototype, it is OK since there would be a lot of software revision.

The Programming Test Clip

The next best thing would be to use these Test Clips. One end would terminate into an 8-pin DIL male connector while the business end would be soldered to a sexy little black clip. Just like a normal clothes clip, this has 4 long wires on each side. They would be inserted inside the clip and at the end of the clip, would be small plastic claws that grips onto the chip.

So, this is great because I can clip onto the chip for programming and re-programming until I am satisfied. But there is a downside which is when I did not clip it to the chip properly or there was too much solder to the microprocessor’s legs. These issues would wear down the small plastic claws. Not only that, with the clip flexing about, it is hard to spot broken soldered wires since they were hidden inside the black heat-shrink tubing.

Since these are more effective than any other methods, I have started using them more often than I can remember. So, this also means, I would need to get more of these replacement clips because throwing away the whole cable because of one component does not make sense.