And Building your P3 Sequencer continues...
The Display Module
The P3's display is a standard 16 character by 2 line device, based on a Hitachi HD44780 or compatible controller chip. These are pretty much an industry standard, and there are a wide range of different LCD modules that will suit. The modules I have used previously are the Powertip PC1602F, with LED backlight.
Since I've tried out a PLED display module, I'll be sticking with these from now on. PLED is 'polymer light emitting diode' - a recent invention that allows a matrix of LEDs to be manufactured in a single piece of plastic-type material. They are more expensive than LCD modules, but have much better contrast, are viewable from any angle, and just look much cooler. The PLED module is the type used in the animated GIF on the main page.
The fairly minimal datasheet for the PLED I use is here.
The pinout of the LCD connector on the main board is as follows:
| Gnd | 1 | 2 | +5v |
| Drive | 3 | 4 | A0 |
| R/W | 5 | 6 | E |
| D0 | 7 | 8 | D1 |
| D2 | 9 | 10 | D3 |
| D4 | 11 | 12 | D5 |
| D6 | 13 | 14 | D7 |
| Backlight: A | 15 | 16 | K |
For some reason, pins 15 and 16 on the LCD Modules are before pins 1 to 14. All the pin connections are in-line on the Powertip modules.
This photo shows what the wiring looks like on a module I assembled:
You might also notice in this photo that I've enlarged the 2.5mm mounting holes on the module to 3mm, so I can use the same screws and spacers as for the rest of the panel mounting boards. M2.5 screws seem very hard to come by.
The PLED board only has 14 pins, as there is no need for a backlight power connection.
Initially, I had problems with the amount of noise the PLED module added to the power supply, so I de-coupled it using a 10R resistor and 10uF cap, mounted directly to the module itself. The end result is not pretty, but works OK.
N.B. These components have now been added to the mainboard at v1.4 - if you have one of these later boards, don't bother fitting them at the module.
Did I mention how nice the PLED displays look ?
I'm looking forward to the day I can get a huge flat wide TV made from this stuff... The contrast makes LCD look mediaeval !
Next Page... putting it together !.
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