SpinStudio Parallel LCD Adapter

This Peripheral module allows a standard parallel HD44780 type LCD display to be interfaced with the SpinStudio system. It includes a potentiometer to adjust contrast, and appropriate current limiting resistors and a transistor to control the backlight. It simplifies the connection of such a device, but it unlike it's "serial backpack" counterparts, it allows the user to learn how LCDs are addressed and controlled. The connection to the LCD is a socket, so that your LCD can be removed when not in use and used for other projects.

note - A 4x20 Hitachi HD44780 type LCD with a soldered 16 pin male header is required for use and not included in this kit.

This interface module is based on the Object written by Dan Miller, located in Parallax's Object exchange. 
Download this object here ----> http://obex.parallax.com/objects/113/


Assembly



First, install the 2 resistors. If holding the PCB as shown in the picture above - Turn the board over and solder the resistors in place, trimming any excess wire afterwards.

The second step is to install the contrast adjustment potentiometer. It will only fit in one orientation, just insert it, turn the board over and solder. The potentiometer is labeled as a blue "C" above.

Insert the 16 pin single row header (red "A") in the top of the circuit board, turn over carefully while holding in place and solder 1 pin in place. Check that it is perpendicular to the circuitboard and properly inserted, then solder the remaining 15 pins.

Install the 20 pin connector (red "B") from the bottom of the circuit board so that the pins protrude from the top. Once again, solder 1 pin, check it's alignment and then solder the remaining 19 pins. Remember, this one connector is soldered on the opposite side as the other components.

Last step - install the TIP41C (Green "A") as shown in the diagram above. solder and trim the leads.

note - the contrast will have to be adjusted prior to use.


Testing and Use

Your Parallel LCD adapter is now ready for use. Plug it into Socket B of your SpinStudio Mainboard. Insert the LCD screen into the module. Pin 1 of the LCD is inserted closest to the contrast adjustment potentiometer. 

Load the Parallel_LCD object into your Propeller Tool program on your computer. Uncomment the "tester" section of code, and compile and run the code on your SpinStudio. You should now have sample text on your LCD.

Study the commands he uses and it will quickly become apparent how to used this object in your own programs.

You can control the Backlight of the LCD screen by setting P8 high (if module is plugged into Socket B), turn it off by setting P8 low, or use PWM to dim the backlight.

Using with a Proto Board

 By replicating a "Socket B" on your Proto Board, you can plug certain SpinStudio Peripheral modules right in. The method of adding this socket is detailed here.



Study the diagram above, you'll notice that the Propeller IO lines align perfectly with the added 2x10 male header we are adding. The only connections that you'll need to wire yourself  are VSS, +3.3VDC and +5VDC. The I2C lines that the SpinStudio Mainboard provides are not necessary at this point, but can be added easily when the need arises. Future Peripheral Modules may take advantage of the I2C bus.

note - if you have the proto board acessory kit installed (VGA/Mouse/Keyboard) the LCD will need to be spaced with an extra 16 pin female connector (not needed if installed on a SpinStudio mainboard), the LCD then rests perfectly on top of the VGA connector. See the following image to see the completed proto board with LCD.



If you are ordering this module to use with a Protoboard, let me know and I will provide you with a free 2x10 male header with your order.

Graphic for protoboard provided by Jeff Ledger   a.k.a. OldBitCollector, used by permission, Thanks Jeff!