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Guest warthog02

8-Segment LCD's for FSBus

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I have some 8-segment LCD's which I hope to use for my autopilot panel using FSBus and FSDisplay. Is this possible? The documentation for FSDisplay mentions 7-segment LCD's only.

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aaaaaaaam ... 7 segment LED's !! not LCD's.If you display 8 on a 7 segment, that is 7 leds, if you count them. But then there is the "." sign that counts as well. So actually a 7-segment display (or LED) has 8 leds or 8 segments.So there is no problem.I am currently figuring out if it is possible to hang LCD's on the Photon output board.If I use 7-segment LEDs, I can hang on 1 board 8 karakters.If however I use the pins of the board separately I have 8*8=64 pins (or 64 single leds OR 64 lines).1 LCD needs 8 data lines + 1 unique line + 2 lines for special actions.Only the 1 unique line is unique (duuh) cuz that's the line which will be high to show to the LCD the data is going to be for that LCD.Now that is a total of:1 LCD = 11 lines/pins2 LCDs = 12 lines/pins3 LCDs = 13 lines/pins...n LCDs = (10 + (n)) lines/pinsThis means that if e.g. I would want to hang 10 LCD's to the interface I need 20 lines/pins. Leaving me 44 lines for single leds.LCD's can have different sizes with different numbers of characters. This means that if e.g. I use 2*8 LCD's, I got 16 characters per LCD. 16*20 = 320 characters.Compare: 1 output card = (8 characters with 7-segments) vs. (320 characters with LCD + 44 single leds)Aint that a big difference !All I need to do now is try if it works and write the code.I will not be possible to write to more than 1 LCD at the same time though. But if the writing goos fast enough it shouldn't be a problem.

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Hi PhilippeThanks for the advice. It's interesting to see how your attempt will turn out on your LCD's. Best of luck.

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>I am currently figuring out if it is possible to hang LCD's on>the Photon output board.As far as I remember, the board uses Maxim chips to drive the LEDs.Since these chips employ a scanning technique, driving character LC Displays with it won't work. (unless you do some really tricky stuff :)If you are really keen on getting multiple char. LCDs running from your simulator, maybe there's a chance that the upcoming character LCD driver board for PHCC could fill the gap. While not designed for it, the PHCC char. LCD daughterboard could be connected to the parallel port (or serial port together with a MAX232 chip).The protocol is easy, it it takes just two wires.This board will be able to drive up to 8 LCDs, maybe even 10.Manuel

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"Since these chips employ a scanning technique"What does that mean ? That the curent for a led that is on is not static 1 ?Ok then but why does the led stay on then ? Or does it flicker so fast you don't notice ?Will the LCD notice the flicker then ?

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>Ok then but why does the led stay on then ? Or does it>flicker so fast you don't notice ?Yes.

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>"Since these chips employ a scanning technique">>What does that mean ? That the curent for a led that is on is>not static 1 ?yes.>Ok then but why does the led stay on then ? Or does it>flicker so fast you don't notice ?yes. This scheme also has the advantage that it consumes less current.Think Television screen or computer monitor... it looks like a static picture to us, but really, there's only one tiny point (at most) lit up at one time (and the phosphorous stuff on the glass makes it glow a little longer though).>Will the LCD notice the flicker then ?It won't work. You need all databits and the control bits static on when the enable line is activated to latch in the new data. This is something the MAX chip can't do.Manuel

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Hmmz ..Don't say I don't believe you but is there no chance that the signal variation is so fast that the LCD hardware will see it as a high ?What if I change the LED for a relais ? Will it open/close very fast ? Or will it just stay closed ? Maybe then I could put relais before wiring to the LCD and power loose from the Photon ?Thing is .. I could use Leo Lacava's board (Eflux) but he told me to try to use my Photon first cuz that's an interface I already have.

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>Hmmz ..>>Don't say I don't believe you but is there no chance that the>signal variation is so fast that the LCD hardware will see it>as a high ?No. Unless you wanna get into probability and statistics (you don't want to do that).>What if I change the LED for a relais ? Will it open/close>very fast ? Or will it just stay closed ? Maybe then I couldI'll try to open/close very fast. You'll probably destroy the MAX chip though. For a relais, you definately need diodes in parallel to it. The diode needs to "point towards" the pos. supply.>put relais before wiring to the LCD and power loose from the>Photon ?>Thing is .. I could use Leo Lacava's board (Eflux) but he told>me to try to use my Photon first cuz that's an interface I>already have.Buying a bunch of relays (11 at least) will probably as expensive (if not more) as building a simple PIC-based LCD driver from the parallel or serial port.If you can wait a few weeks, I might have the PHCC LCD driver done. :)Manuel

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>Thing is .. I could use Leo Lacava's board (Eflux) but he told>me to try to use my Photon first cuz that's an interface I>already have.Oh, my bad! I thought the output module for Photon used latches for LEDs and the MAX chips only for the 7-segs.In that case you can't use the MAX chips. You'll need to make your own output module using serially loaded shift registers with output latches for use with LCDs and connect it in place of the MAX boards...but I don

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Hmmmmz .. now you people are losing me :(Don't expect me to go make hardware :(So if Photon doesn't work I'll need other options.Something like a Velleman K8000 comes to mind ... ?Some folks used to use that for their sim. Have no idea what it can do.Or else Leo, if I find nothing else .. perhaps I should go for your module then afterall.

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>Hmmmmz .. now you people are losing me :(>>Don't expect me to go make hardware :(>>So if Photon doesn't work I'll need other options.>>Something like a Velleman K8000 comes to mind ... ?Doesn't the Velleman stuff come in form of kits ?There you'll have to solder things together as well :)>Some folks used to use that for their sim. Have no idea what>it can do.It uses a two wire protocol called I2C to talk to its individual modules.Check the "Velleman K8000" column at http://cockpit.varxec.net/electronics/inte..._solutions.html>Or else Leo, if I find nothing else .. perhaps I should go for>your module then afterall.

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> Doesn't the Velleman stuff come in form of kits ?> There you'll have to solder things together as well :)They do sell completed things :)But the K8000 is a DIY of level 5 (hard).> Check the "Velleman K8000" column at http://cockpit.varxec.net/electronics/inte..._solutions.htmlAvailability is wrong for the K8000... Velleman doesn't sell on his website, but trough his dealers

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