LCD Displays (Alarm Clock project)

Armored Cars

I am building my own alarm clock and need to know roughly how to use a direct drive LCD with an SX.· I am using a four digit, 8 segment LCD.· If someone could just tell me how to use an eight segment single digit LCD that would be great.

Forrest

Nuts and Volts #117 shows you how to drive a 7 segment LED display www.parallax.com/html_pages/downloads/nvcolumns/Nuts_Volts_Downloads_V6.asp

Jon Williams

You'll need an appropriate display driver for that LCD -- the LCDs written about are character LCDs that have them built in (this is usually not the case with clock-type displays). The LCD vendor should be able to recommend an approrpiate driver.

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Jon Williams
Applications Engineer, Parallax

Armored Cars

Here are two displays I am looking at using. It looks like I will need to program my own SX's to dive them. On the 14 segment display I think I will need to rapidly switch between the two digits so it looks like they are both on.

http://www.fairchildsemi.com/ds/MA/MAN8410.pdf

http://www.fairchildsemi.com/ds/MD/MDA6440C.pdf

This brings me to another question. Since I will need multiple SXs communicating with one another how do I ensure the clock cycles match? If I have two SXs with the same frequency occilators is that enough or do I need to run both off the same occilator (is that possible?).

Jon Williams

Those are LEDs, not LCDs -- big difference.· Have a look at an LED display driver I did with SX/B 1.1 (easier now with 1.2) back in the January edition of Nuts & Volts magazine:

http://www.parallax.com/dl/docs/cols/nv/vol6/col/nv117.pdf

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Jon Williams
Applications Engineer, Parallax