I found an old beaten-up CD player a while back, and decided to take out the human interface card, with the LCD and buttons on it.
In a previous episode, I managed to get the LCD to do something. Now, I will try to let it do exactly what I want it to do!
The first task is to find out what segments is controlled by what segment to the chip(s). In Controlling the card, I found out how to send the chips data — basically I have to send an 80-bit sequence to the two chips, of which 2*4 bits are chip control data. This leaves 72 bits of data to control 57 segments, so some of the chip’s capacity was unused.
My first plan of attack is simple: in the previous episode I learnt how to listen for keypresses, so my idea was to make a simple keypress-driven loop trough all the 72 data bits, to see which segment will light up.
Continue reading “Using the LCD”