On Tue, 3 Jan 2006, Philip Pemberton wrote: > In message > Peter wrote: > >>> I've worked out the pinouts for the display. It has 27 pins, and seems to >>> have the segments and backplanes multiplexed three ways. Very odd... >> >> Very common, you mean. > > Now I've done some research, I will amend my previous statement. Common > indeed, just not with the segment/common wiring my LCD has. I've seen the > datasheet for Maxim's triplex display driver, but near as I can tell there's > no way to use it with these displays - the segment/common wiring is similar > in some places, but completely different in others. > >> You can drive such a display directly with >> tristate outputs. Tristated outputs must be 'pulled' to the relevant >> intermediate voltage with a resistor, each. > > So you keep the pins idled at about 2.5V and either pull high, low or float > them? Hm. Sounds like a plan, but it's going to need a fair few resistors... > Probably 27 (one for each segment/common) and two for the voltage divider. > Owch! Use 4 8x1 resistor rows and an opamp as driver for the false 'ground'. It is better if you simulate the 3-phase LCD drive using some graphical tool, otherwise you will have trouble understanding it (ignore the phase alternation in the beginning). Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist