setCursor example in Arduino "learning"

Forum 2005-2010 (read only) Software Troubleshooting
1

Hi,

For the learning example in arduino website LiquidCrystal library > setCursor

As I understand the syntax of lcd.setCursor is lcd.setCursor(col, row)

I think the descriptions above the code :

lcd.setCursor(0, 0); // top left
lcd.setCursor(0, 15); // top right
lcd.setCursor(1, 0); // bottom left
lcd.setCursor(0, 15); // top right

should be

lcd.setCursor(0, 0); // top left
lcd.setCursor(15, 0); // top right
lcd.setCursor(0, 1); // bottom left
lcd.setCursor(15, 1); // top right
:wink: :wink:

So the example code works fine( at least on my lcd module), but be aware that in lines 55 to 62 :
variable thisRow is actually referring to the column
variable thisCol is actually referring to the row

I tried this on arduino 0017

Cheers

2

big trumpet:

This is not the only place where the rows and columns have been interchanged. It appears that some of the Playground pages were edited incorrectly several months ago. A few days ago I sent a private message about this to the person who I believe made those changes but I have not received an answer back.

I started a thread about this last Friday (http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1259290563) but as of today I am 0 for 68 on responses.

I don't have much C programming experience and I am afraid that if I try to fix things myself I might just make them worse. None the less I plan to start soon if I don't hear back.

Don

3

Hello Floresta,

I think the guy who's writing the LiquidCrystal library has done a good job, but learning examples just need to catch up a bit. :stuck_out_tongue: :stuck_out_tongue:

I tried the "HelloWorld" again, but it seems working fine. It is set :
lcd.begin ( 16, 2 ) for a 16 characters x 2 rows / lines display

In the funny world of lcd displays, the (0,0) is top left, which is quite different from conventional x,y co-ordinates in the math books. I think this is confusing sometimes.

Cheers

4

big trumpet

I think the guy who's writing the LiquidCrystal library has done a good job

He's a "she".

The library is fine. The Playground description is OK but could use some work. The 'Hello World' example in the Playground is FUBAR.

Don

5

should be

lcd.setCursor(0, 0); // top left
lcd.setCursor(15, 0); // top right
lcd.setCursor(0, 1); // bottom left
lcd.setCursor(15, 1); // top right

dont you mean "lcd.setCursor(15, 1); // bottom right" ?

6

Really? You make a post just to point out a typo?

......
:-?

In the funny world of lcd displays, the (0,0) is top left, which is quite different from conventional x,y co-ordinates in the math books. I think this is confusing sometimes.

There are alot of little things like this to get used to with microcontrollers :smiley: ... such as counting starting at 0, I made many a mistake when first starting out.. always start counting at 1 and mess things up. :stuck_out_tongue:

And I got an LCD that has 131x131 pixels... and it's the same way! Makes for a hassle when you're trying to remember exactly where that pixel would be on the screen. :stuck_out_tongue:

7

CaptainObvious: making a post to point out a typo is a good thing! We want to fix problems like this. Don't judge the posters here, please.

8

Agree, however typos in code are educational, typos in comments not as much.

Lefty