SPI LCD

The SPI_LCD board

This is the documentation page for the SPI_LCD board by changing a solder-jumper.

Assembly instructions

The board comes fully assembled.

Possible Configurations

The board can also be configured for I2C operation.

The second SPI port can be used as an ICSP connector.

External resources

Datasheets

The fets: http://www.irf.com/product-info/datasheets/data/irlml2244pbf.pdf

The CPU: http://www.atmel.com/dyn/resources/prod_documents/doc8006.pdf

Pinout

The SPI_LCD board has two SPI connectors. SPI connector pinout

LEDs

none.

Jumper settings

There are two solder jumpers. The one between the two 6-pin SPI connectors controls the function of the SPI connector furthest from the CPU.

In the default configuration the second SPI connector is a daisy-chain connector for the SPI bus.
In the other configuration, the second SPI connector is the ICSP connector.

The second solder jumper connects "rs" and "vo" of the LCD together (and to one pin of the attiny44 controller on the board) in the default configuration.
In the other configuration, the pin used for SPI slave select can be used as the RS pin. This is used in the I2C configuration.

There is a 10 mil (very small) PCB trace in the solder jumper in the default configuration. You'll have to cut this trace to move the solderjumper to the other position. If you later decide you want the other configuration again, some solder-wick can be used to remove the solder from one position and then it can be added to the other position.

Programming

To display things on the LCD, you need to send things over the SPI bus to the PCB. The protocol is explained here. If you have an older version, 1.2, the protocol is explained here

An example application is called "demo_lcd" and is available at [the bitwizard software download directory] . This appplication was written for the ftdi_atmega board from bitwizard, but can also be used on an arduino. But you'll have to download the hex to your board by hand after compiling.

For arduino, a sample PDE is available, called ardemo_lcd.pde, also at [the bitwizard software download directory] .

Future software enhancements

• Lock the address. (require a sequence of commands to change the address).
• Allow setting of the current eeprom address.
• Allow reading/writing of the eeprom.

Changelog

1.2

• Initial public release