Parallel Port?!

[thelocust]

Well, my <A href="http://thelocust.org/cajun/">previous project box for an MP3 system</a> had serial ports, and it worked WONDERFULLY with my CrystalFontz display.
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Now, I've moved on to a smaller box, the "Book PC", which only has USB and Parallel ports! Is there any way to wire a cable to use the parallel port for the CrystalFontz 634? I don't really want to spend another $20 on a USB-serial converter.

[CF Tech]

It is possible to drive the 634 or 632 in "SPI" mode from a PC's parallel port.

Basically you assert the /SPI_CS, then clock out 8 bits using DATA_IN and SPI_CLK, then de-assert the /SPI_CS. Timing is not critical as long as the clock period is at least 55us (http://www.crystalfontz.com/products/632/spi.html).

We have a BC++3.1 DOS demonstration program that will talk to up to 8 of the displays at once through one parallel port. It is not particularly pretty code, but it does work.


Send an email to techinfo@crystalfontz.com to request a copy of the program and the source if you would like it