Do you have a logic analyzer like Saleae, or even one of those rp2040-based ones?

Do you hate plugging up all the signals when you want to use your logic analyzer on a multi-channel problem?

While working on RGB matrix support on the Pi 5, I sure did! But then I remembered that Adafruit has the parts I need to make some cables that are quick to connect & disconnect from my logic analyzer.

In my case, I'm plugging into a Rigol MSO1074, but I might also want to use my Saleae in the future, so I made up two 2x4 blocks. This way, I can use the connectors on either device.

It's quick and easy and best of all you don't have to crimp any connectors because the pre-crimped jumper wires are right there in the Adafruit store.

Start by grabbing the parts you need. Get a packet of housings for the "project end" and the "logic analyzer" end, as well as the correct jumper wires (male/male, male/female, or female/female) for the connectors.

For instance, I was connecting the 2 row male header of my logic analyzer to the 2 row male header on the Adafruit RGB Matrix Bonnet, so I used Female/Female jumper wires, a pair of 2x4 housings from the small dual row wire housing pack, and a single 2x10 housing from the large dual row wire housing pack. (there are actually 2x8 pins, but the 2x10 housing fits the space of the keyed connector better, reducing the chance of plug mistakes. A keyed housing would be better, but then I'd be off to digikey to look for one)

Now, tear off some wires from the set of jumper wires. I worked in groups of 5, so that each 2x4 housing for the logic analyzer end had 4 signal wires & 1 GND wire.

I connected 8 different signals, somewhat arbitarily: 4 RGB data lines, 1 address line, and 3 control lines.

Double check the position of each signal & GND, and make sure you have at least one GND signal (but more ground wires are better for signal integrity! The ideal is to have one GND between each signal)

Once you're satisfied you've got the correct wire at the correct position, insert the wire into the housing until it clicks firmly into place. The orientation of the crimped pin is important, it will only latch one way.

If you make a mistake, it's not the end of the world. Frequently it's possible to free a "locked in" connector. Here's the procedure I follow: First, push the pin as far forward in the housing as possible, opening a gap under the plastic latch. Then, carefully insert a jeweler's screwdriver under the latch. Then, pull back on the pin. When done properly, this frees the wire & leaves the latch intact. However, if you bend the latch out too far it deforms and will no longer retain a wire when one is re-inserted. 

My HUB75 Adapter Pinout

(Logic Analyzer Position - Wire Color - Function)

• 0 - White - Latch (active high)
• 1 - Gray - Output Enable (active low)
• 2 - Purple - Clock (latch data on rising edge)
• 3 - Blue - Address "C"
• 4 - Green - Data "R1"
• 5 - Yellow - Data "G1"
• 6 - Orange - Data "B1"
• 7 - Brown - Data "R2"
• Black - Conn #1 GND
• Red - Conn #2 GND