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LCD Display Driver?

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DaKandEKid

New Member
I need 14 and growing i/o pins for my application and i have a parallel LCD hogging 7 of the pins.

I've seen LCD Display drivers before on the net and was wondering if anyone had any experience with them.

Like, do they have a serial data input and a parallel output and there is a ASIC chip out there that's very low cost in volume?

Serial LCD's are just way to expensive for our application.

thanks in advance,
~blake
:?:
 

TheAnimus

New Member
Hi what type of LCD is it? Alphanumeric i am guessing the hobbiest standard (hey if industry has one y can't we) is the HD44780 this is simple to use, has R/^W (8080) style interface.

This means u can save a pin if u don't need to read from the LCD, and do all the timing with NOP cycles, rather than poll'ing the chip.

If your useing a graphic controller, at the risk of been flamed a recomend the SED133x range.

Yeh i must admit i don't know y serial LCDs are so expensive i mean look at matrix orbital etc. they just seam to live to rip off the stupid modders of the world that can't figure out how to wire a potentiomiter in line with some wires from a parport!
 

DaKandEKid

New Member
I'm going to use a parallel lcd... most likely hd44780 chipset unless i find another lcd which is a lot cheeper.

It's an alphanumeric lcd.

Just curious about the LCD Display Drivers maxim and other companies make. Are they mainly for the clock displays and such... or are there ASICs out there that are a cost effective solution to save i/o pins of your microcontroller rather then investing in a uC with more i/o pins.
 

TheAnimus

New Member
Display Drivers is a vauge word you c, a display that has an interface like a 44780 is already "driven" that chip controlls the timing and re-freshes the LCD for you. A lot of the drivers are for 7-segment LCDs infact u can get PICs with these built in.

If you want to save pins on the uC then u can use a standard TTL shift-register and a total of 3 wires on your uC.

Using a Rotate Left File instruction you can easly clock the data out!
(if you get stuck just post and someone will try and whip up a routine to do this for you, but it should be very simple)
 

DaKandEKid

New Member
thanks for clearing that up for me. I had a hunch that the LCD display drivers weren't just to make a parallel lcd a serial lcd.

and thats a great suggestion on the shift register.

I'm going to do that.

Thanks for your help
~blake
 

dsdsds

New Member
The link below describes what TheAnimus was talking about. I'm currently working on 16f84 project interfacing 3x4 keypad to LCD display. 4 pins are controlling keypad and 3 pins for the LCD. I haven't got it working yet because I'm so crappy at dubugging (and programming). I wonder why I like this so much. I'm glad programing uc is not my day job!

http://www.rentron.com/Myke1.htm
 

Exo

Active Member
One could use a 4094 serial shift register to create the 8data bits.
The 4094 acts as a serial to parallel converter. This way you would only require 4 i/o pins on the pic to control the display.

PM me if you want scematics and/or code examples
 

spyglass25

New Member
Hi
I would like to get some Schematics and code examples for 3 wire lcd (cd4094) or 74ls595, if you emailthem to me

Thanks

Alnoor
 

AtomSoft

Well-Known Member
I would recommend getting either the Cheapest PIC, AVR or even a CPLD and coding your own Serial Converter for the LCD. This would be way cheaper than buying them made but requires some time to make the code and then program each individual IC. But the money it will save is great!
 
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