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Let's Do This
Time to get down to the brass tacks of this article, the assembling of the harness. As I commented earlier, you can use the IDE hard drive cable or choose not to. You can even scrimp further and omit the plastic sub-connector hood if you'd like to really go ghetto. Don't be surprised if the infamous 'cannot establish a connection' note continually riddles your pc screen while attempting to program as a result. With the hood properly screwed into the printer port connector in the back of your PC and your modified IDE connector plugged snugly into the programming ports of the board, you should have little troubles reprogramming your board with this fantastic logic enhancement. Be sure to insert the pins of the harness into the programming ports of the board in the correct orientation. There are 2 ways you can plug it in. If you choose the wrong way, it is possible to damage the board.
We'll start by cutting one end of the IDE cable off. Be sure to leave enough length on the cable to reach around the back of your PC comfortably, otherwise you'll be laying on the floor holding the on/off button on your Imp while trying desperately to hit the right key on the keyboard to initiate the software transfer. After cutting the end from the cable, count 6 wires from the end and make an incision with an Ex-acto knife between the 6th & 7th wire. You can either continue the cut with the knife or simply pull the wires apart all the way to the plug. Using the hack saw blade, cut into the 4th slot of the IDE connector. Cut it all the way to the bottom and use the Ex-acto knife once you get to the wire area. Be careful not to cut into the 6th wire or you may create a short in the cable once it's all together. To rid it of any jagged edges lay some sandpaper on a flat surface and sand the cut portion of the connector by scraping it across the sandpaper till it's nice and flat. Make a cut between all of the 6 wires at the other end of the cable about 1" from the end to separate them. Strip the plastic insulation off the wire to about 1/8" from the end. Make 6 small pieces of masking tape to use as labels for the freshly stripped wires. Wrap 1 piece around each wire so there is a flat area to mark numbers on.
Inscribe the numbers corresponding to the schematic into the sides of the plastic connector you just cut out of the IDE cable with the Ex-acto blade. You could use a small piece of masking tape and mark the numbers as an alternative. Remember: The plug will be facing down and the schematic(programming ports of the board) is facing up. If you disorientate the numbers, you will end up connecting the wires to the wrong pins and the programming won't work. Cut about 8" of wire from the spool of 24 gauge wire. Either connect it to one pole of the transformer or wrap a portion of it around one post of the 9 volt battery, whichever you choose to use. Connect the circuit tester clip to the other post of the transformer or battery. Insert the end of the 24 gauge wire into one of the receptacles in the plug of the IDE harness. Let's use #3 as an example. Touch the end of the circuit tester randomly to the 6 stripped ends of the harness. When the light is activated in the circuit tester, this is the wire that will attach to the MOSI 220 ohm resistor that will be soldered to pin #9. Mark the number 3 on the small piece of masking tape wrapped around the wire. Continue doing this with all of the other receptacles of the plug until you have all the wire ends marked. You will have 1 wire left unmarked. This does not connect to anything. Once you have everything soldered in you can just snip the frayed wire end from this wire. Just to be on the safe side, test every wire once again to make sure they are all marked with the correct numbers before proceeding.
It's time to start soldering the 5 marked wires to the sub-connector. You will either solder directly to the connector or the removable pins, depending on what type of connector you purchased. If you're using the removable pins, you'll need to first crimp the pins to the 220 ohm resistors(# 2 & 3), straight in wires(#1 & 5) and 8 ground wires(#4). Once crimped, use a minimal amount of solder to be assured of a solid connection. All I can say about this portion of the assembly procedure is plan ahead. All of this assembly has to fit inside of the plastic hood. Bare wires must not be touching each other nor any of the ground wires or the metal wires of the resistors. I could type 3 paragraphs of precautions but you'll just have to use a little bit of common sense here. Use the schematic and photographs as a guide to where the wires and components are attached. The wires of the resistors must be cut to size and you can slide them snug all the way into the removable pins. Save all of the excess wires from the resistors because you will need them later on in this task. When attaching all of the ground wires, solder them into the sub-connector and be sure there is some excess. Once they're all soldered, twist them together(see photograph) making sure they will fit into the plastic hood. Cut any excess off then solder the corresponding wire from the harness to them. The last thing I will say about this portion of the assembly is once again, plan ahead before you solder. It will prevent you from having to do things more than once.
Once everything is soldered up and snug, you can put the assembly into the plastic hood. Wrap a piece of electrical tape around the portion of the harness that the metal hood retainer will be clamped onto(see photograph). This will assure a nice tight fit of the retainer and prevent the wires inside from being pulled and detached from the resistors and sub-connector. The small screws and rectangular washer screw into the side holes of the plastic hood opposite the plug face of the sub-connector. Once you plug it into the printer port of your PC server, the screws will hold it snugly in place once they're completely turned in.
All that's left to do now is make some pins that will fit in the programming ports of the Impulse Cricket board. This is where those wire ends that I told you to save from the capacitors come in handy. Just cut them all to the same length and insert 5 of them in the active receptacles of the IDE cable harness connector you modified. This portion of the assembly fabrication is where purchasing the sub-connector with removable pins has an advantage as well. Since you've only used 12 of 25+ pins, you have extras to spare. The wires of the capacitors fit snugly into these pins and it just so happens that the pins fit perfectly in the programming ports of the Cricket board(see top photograph). Crimp them to the wires, use a little solder to hold them in place, slide the opposite end into the IDE cable harness connectors and voila!........you've made a great functioning ECS programming cable.
Now all that's left to do is go to Dave Cichy's Krik-it site and download ECS onto your Impulse board, then tune it after reading the Tuning Your ECS Programmed Impulse article on the SPPS site and you're ready to mow faces. Dave should be commended for the part he has played in preserving ECS for all to freely add this fantastic logic enhancement to their Impulse boards. I'm in hopes that this article may have cleared up any obscurities that a lot of Impulse owners may have had about making one of these cables to reprogram their Impulse Cricket boards with this fine free Enhanced Cricket Software.
Technical Information
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