PicoLCD

The folks at Mini-Box were kind enough to respond with both schematics and source code for my PicoLCD 20x2 display. The Mini-box page lists it as "out of stock" and they have several snazzier products now but this is the one that I have.

Now I can do something fun with it. Well. Let's say "More fun." I was already able to get it going on 8track with the generic lcd4linux program, but I want to be able to use all the extra ports on it. What I have in mind requires programming the actual board.

Some specs:

LCD: 20 characters wide, 2 rows, with backlight
CPU: Microchip 18F4550 (Microchip page)
This chip has 32K of Flash, 2K RAM, a 13 channel 10-bit ADC, a couple comparators, and of course the 11Mbps USB port.
One bit switch
64k EEPROM
IR port

There are many interesting features on this board considering on the surface it's just a 20x2 LCD. A companion product from Mini-box is a board with buttons and an IR receiver on it. I don't have one of those, and it would not fit in 8track anyway.

One bit switch NC7SZ384: The board has connectors for "power in", "power out", and a "power button". The power in and and out are wired up to the switch. The "power button" is simply connected to a port on the CPU.

Connection to host system

There are cables available but alas I neglected to order any.

The Mini-box docs show a 5 pin connection, but my board has only 4 pins, no ground wire so I ignore that connection. On my Epia motherboard I connected to the on board USB using a 6 pin cable that I had handy. The Epia gives me 4 options, I choose a set up that leave the other three available. It looks like this

LCD    CABLE  EPIA
        
1 V+   6 YE    10
2 D-   5 GN    12
3 D+   4 WH    14
4 V-   3 BK    16
5 GND  2 OR    nc
       1 RD    nc

Using the PicoLCD with lcd4linux

Not going to go into a lot of detail here, but this is available for most Linux distributions and it supports the PicoLCD 20x2.

You have to enable the 20x2 by commenting out the default setup line and uncommented the 20x2 line in the lcd4linux config file.

Then you can pick and choose what you want displayed from the included tools or write scripts for lcd4linux to run.

Working with the SDK

Mini-box provides an SDK so that you can write your own host-based code. The SDK includes a simple sample program.

You can use the sample program instead of lcd4linux if you don't want to do programming.

Programming the PicoLCD

You need a development system running Windows to use Microchip's PIC development tools. There are tools and compilers available for Linux but Microchip's MPLab is so good I am willing to use Windows to run it.

The IDE and assembler is MPLab. In addition there are C compilers available. I will be trying the Hitech "Lite" (free) version. The nonfree version is $500.

to be continued