Colour LCD or Greyscale?
Today, a lot of people have come to expect colour graphic screens. As soon as they see this they instantly assume it’s touch screen too!
The world of hobby/professional electronics also needs to keep up with this ideology!
So when it came to decide which type of LCD to use, I originally thought to use a Black/White LCD with buttons!
After hunting for LCDs I found that there are two types, the ubiquitous KS0108 and the new ‘Chinese font enabled’ ST7920. Both are very similar, but the ST7920 supports a type of write only 3 wire serial access. It has obviously been designed to be used in a parallel interface! The 128×64 LCDs are also very very popular so costs should be cheap! (They’re about $10-15USD on ebay/alibaba)
So I have designed by circuit to accommodate an ST7920 and I ordered one. However, after drawing the circuit, I took another look at LCDs on Alibaba and ebay. I found that there are colour TFT 3.2″ LCDs 320×240 with resistive TOUCH PANELS! WOW! Lets move into 2010 in style! Resistive touch panels! These are about $15-$20 on ebay and alibaba. You can see, for an extra $5 you get 262K colours, and a touch screen, some even have an SD Card slot on there!
These TFT LCDs are mainly based off the SSD1289 (LCD Controller) and ADS7843 (Touch Panel Controller) and are interfaced off the usual 4wire SPI method! Use only 5 wires and you have access to the whole LCD! Terrific! So I took advantage of the high NZ dollar and purchased one of these colour LCDs… only time will tell what will be used.
Also Colour LCDs require a lot more memory too! So we’ll see what’s feasible!