Successfully mapping out the segments for a food thermometer LCD had a nice side effect of improving my soldering skills. Armed with this experience, I feel more confident tackling the task of deciphering LCD controller communication protocol. Earlier I had successfully reassembled and powered up the circuit boards from a 1998 Toyota Camry LE stock tape deck. Now I intend to go beyond looking at pretty lights and see if I can control its front panel.
That front panel connects to the main board through this connector, which has labelled most of its contact points. Since I want to probe their behavior in a running system, I wanted to preserve the ability to plug it back into the mainboard. I had the soldering iron all warmed up ready to solder to the visible surface-mount contacts above and below this connector, but then I thought of a better idea.
Its mating connector is soldered to the mainboard, and it is a through-hole connector which meant there are exposed pins on the bottom of the mainboard. These pins are finer pitch than the 0.1″ I usually work with, but through-hole pins are still more familiar to me than surface mount pads. So I soldered my wires to these pins.
These wires are then brought out to another strip of perforated prototype circuit board, and a row of 0.1″ pitch headers.
Which then plug nicely into a breadboard for easy probing and experimentation. Thanks to the labeled connector, I already know which wire is ground so I connected a bare loop for my instruments to use as reference. Next step is to probe the remaining pins to determine their voltage range.