Shop OBEX P1 Docs P2 Docs Learn Events
Sparkfun LCD driver problem — Parallax Forums

Sparkfun LCD driver problem

tonocastillotonocastillo Posts: 12
edited 2012-05-26 11:59 in Propeller 1
Hello

I have been playing with a LCD from Sparkfun:

http://www.sparkfun.com/products/790

I have tried the LCD drivers for HD44780 interfaces but all I get is the full block blinking blocks in the first line of the LCD.
Nothing in the second line.

I am using the 4bit mode driver found here:

http://obex.parallax.com/objects/106/
and here:
http://obex.parallax.com/objects/667/

with no luck. The same thing, just blinking blocks.

Any ideas of what could be the problem?
I checked if the solder was done properly and everything seems to be fine.
I connected 4 pins:

LCD ---> Propeller
DB4 ---> pin 11
DB5 ---> pin 10
DB6 ---> pin 9
DB7 ---> pin8

RS = 19
RW = 21
E = 23

Not sure if any of you have had experience with this LCD?

Thanks in advance.

-Tono

Comments

  • JonnyMacJonnyMac Posts: 9,195
    edited 2012-05-18 10:28
    I haven't looked at those LCD objects (I have my own: http://obex.parallax.com/objects/474/), but they may be expecting the buss pins to be contiguous and in ascending order (as my object does).
  • Ding-BattyDing-Batty Posts: 302
    edited 2012-05-19 07:26
    tonocastillo wrote: »
    LCD ---> Propeller
    DB4 ---> pin 11
    DB5 ---> pin 10
    DB6 ---> pin 9
    DB7 ---> pin8

    I suspect Jon diagnosed the problem correctly -- DB7 from the display should connect to the higher-numbered Propeller pin for the ObEx object 667 to work correctly.
  • tonocastillotonocastillo Posts: 12
    edited 2012-05-25 21:54
    Ok nope. Lately nothing I'm doing is working.
    I guess it's because I want to do so many things at a time.

    I tried both of your codes and I can only make all block of the LCD to blink.

    Will try it with some pull up resistors in the DB# pins.

    Let's hope this makes a difference.

    If not, I'm going to go with a parallax LCD.

    Thanks.
  • JonnyMacJonnyMac Posts: 9,195
    edited 2012-05-26 00:31
    It's always best to start with basics and then move forward. I have been using these kinds of character LCDs since 1994 when I first started with the BASIC Stamp 1. Once you get the connections sorted, the rest is pretty easy and falls into place.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2012-05-26 01:01
    Are those LCD ok at 3.3 Volts ?
  • JonnyMacJonnyMac Posts: 9,195
    edited 2012-05-26 11:59
    No, they need 5v. This is not a problem for the Propeller. If one wants to read from the LCD (busy status and cursor position) then 3.3K resistors should be inserted between the LCD data pins and the Propeller IO.
Sign In or Register to comment.