HD44780 LCD text display issue - Raspberry Pi Forums

-

i've been following adafruits tutorial wiering lcd in 4-bit mode:
http://learn.adafruit.com/drive-a-16x2- ... i?view=all

have 20x4 , 16x2 display. both hd44780 compatible. use similar setup tutorial -pi gpio cobbler connected breadboard display.

when using 16x2 display in breadbord works fine.

however, when plugging in 20x4 lcd same way wont display text properly. shows irregular pattern of faint vertical lines. lines 1px wide , 2 rows high. when recieves new text data lines change position. seems has @ least initialized , in way responding data input.

displays have different pin-outs have adjusted that. other difference can think of resolution, i've tried running python script written 20x4 , no success. anyway shouldnt matter right?

other things have tried: adjusted pot contrast, added resistor between anode pin , 5v, re-soldered pin headers, checked continuity, triple checked pinout , wireing.

wrong here? timing issue? if display broken, can check in way?

ok, i've realized did wrong!

had removed metal frame covering lcd display glass in order fit instrument panel. couldn't imagine had other purpose protect lcd. apparently lcd won't display text without it.
pretty simple solution turns out.


raspberrypi



Comments

Post a Comment

Popular posts from this blog

Thread: PKI Client 5.00 install (for eToken Pro)

-
my company uses aladdin etoken pro authentication on vpn connections. etoken requires pki client application on client machine before os recognize it. app , token work fine on xp, use ubuntu on laptop. aladdin has offered linux version of client, rpm. convinced our internal guys rpms, , i've been trying work couple days. begin with, hp pavilion dv4-1435dx laptop running jaunty 64-bit. - started out converting .rpm .deb using alien: code: sudo alien -d pkiclient-5.00.28-0.x86_64.rpm - worked fine , got nice little .deb - next, ran .deb install client: code: sudo dpkg -i pkiclient_5.00.28-1_amd64.deb - , executed without errors/issues. pdf rpm said there should launcher @ applications > etoken > start etoken pki client, didn't exist. figured might because installed deb instead of rpm. bounced box, still wasn't there. no big deal... - install network manager can configure vpn connection use token: code: sudo aptit...
Read more

ATmega2560-Arduino Pin Mapping

-
hi community, in last days working on project using arduino mega 2560. on planning pin using found bugs in atmega2560-arduino pin mapping . if right there labels (such pwm) in 'mapped pin name' @ wrong row ( mixed pin numbers right one...) in attachment openoffice calc , pdf file corrected table. ( hope ;-) ) i post here tab separated table : code: [select] arduino mega 2560 pin mapping table atmega 2560 pin out arduino mega function nr name function function function mapped pin name function function datasheet 1 pg5 oc0b digital pin 04 pwm 2 pe0 rxd0 pcint8 digital pin 00 rx0 (usart0 receive pin, programming data input or pin change interrupt 8) 3 pe1 txd0 digital pin 01 tx0 (usart0 transmit pin or programming data output) 4 pe2 xck0 ain0 (usart0 external clock  input/output) 5 pe3 oc3a ain1 digital pin 05 pwm 6 pe4 ...
Read more

Crossfader Arduino Tutorial

-
hello i'm super newb please don't bash me much. i'm using led's , i've connected them correctly (finally) , wondering why program here ( http://www.arduino.cc/en/tutorial/colorcrossfader ) doesn't work? say's haven't declared crossfade. read directions on top , said crossfade needs used list order of colors. isn't declared in main part (void loop() )? or need declared before? nevermind void on bottom , needed before voidloop. lol anyways playing rgb led's wondering if has specific way of making them fade in , out different colors? (brightness , color mixing) code: [select] /* * code cross-fading 3 leds, red, green , blue (rgb) * create fades, need 2 things: *  1. describe colors want displayed *  2. list order want them fade in * * describing color: * color array of 3 percentages, 0-100, *  controlling red, green , blue leds * * red red led @ full, blue , green off *   int red = { 100, 0, 0 } * dim white 3 l...
Read more