As an absolute beginner , I seem to have a 'simple ' ?! problem with 'example programmes.My board is classed as Arduino Uno R3, with 'blink', pre-installed OK ..To get the 'feel of things' I then tried , again, in examples " Hello World " with llC TWI 1602 Serial Backlight LCD .attached and powered up; 5 volts ,,with A4 A5. also tried with SDA and SCL Com port 3 upload validated , squares show fine on display ,, And thats all!!!
Any- thing I'm doing wrong ? please help
(deleted)
Squares on the LCD display indicates that it has not received any commands - but they let you adjust the contrast (which, by default, is often adjusted such that you don't see anything on the screen). There should be one row of boxes, one row no boxes (if contrast is adjusted too high, you'll get two rows of boxes, indicating that both black and white pixels are showing up dark)
One common cause of communication problems with I2C LCDs (provided the sketch is otherwise functioning) is the I2C address - those backpacks come in two common versions, with the I2C port expander varying in which I2C address it uses (there are also a few versions with different port expanders entirely - I haven't seen these for sale recently though). Check that you are using the right address for the ones you're using (check datasheets on the port expander part number on your board).
Of course, if you're not able to upload the sketch at all (this isn't clear from your post), you need to solve that problem first.
Hi
spycatcher2k.. apologies for the delay in replying. However, thanks for your reply'' In answer to the first of your questions .. As stated , as a beginner I am only at the stage of trying 'examples' , I repeat, Blink is already pre- installed , works fine; the board is an ELEGOO Uno R3, the only other ( 'example') program I tried was 'Hello World' 'which as you would expect loaded ' compiled ' OK no errors 1111
If Blink is still working on your board then you have not loaded any new code into it. Perhaps you have "verified" (compiled) it without errors but you have not done "Upload"?
Steve
Hi DrAzzy, again, my apologies for the delay, and thank you for your interest...Again, as a complete beginner , I assumed by connecting the /TWi 1602 with I2C (blue), to the appropriate 5v power and analogue or SCL /SDA sockets, I expected to see the printed words ! Obviously I was wrong.... completely overlooking the I2C address ? !! These are items I so very much need to learn about.. When I am happy with the simpler aspects of 'example ' progs, ? then hopefully I can really start on the long learning curve ?? again, many thanks
Hello slipstick; thanks for the reply, To reiterate, blink is pre-installed on the board - as purchased.
When I tried 'Hello World' from 'examples'-- verified and Uploaded, of course the original 'Blink' prog disappeared to be replaced by the new 'example ' sketch. !! As I've already seen , my I2C display address was not included, which would appear to be the 'problem' thanks
Download an I2C address scanner and run it on your Uno. That will show if the I2C device is connected properly and what its address is.
Well, well ,, yet another problem.. Now my PC Windows 10, will not accept the Arduino board !? After trying to get the I2C address , told to 'check my security' etc, also, when attempting to re- download IDE. . The only indication on ' This PC,' devices , is 'usb serial device (com3) ' ???? Have no idea what is happening, tried a couple of USB leads (USB2) (does not accept USB3 ).. no change Get the expected 'noises ' on inserting my board , but thats it, I was hoping to see the Arduino app somewhere on the taskbar ??
Yet the 'Blink' sketch is still running on the board ??? Just don't get it
Rebooting usually works. Why were you trying to download the IDE again?
When my new UNO wouldn't connect, it was because of com ports 4 & 5 being used by all things - MSWord... rebooting closed word and solved it.
- Do adjust the contrast, it may be a simple little trimpot on the LCD board.
- If you got it from Amazon, check feedback and Q&A. Often much is posted on experience in getting it working. Especially the I2C addr.
- Give yourself an hour of tooling around and then put it aside.
Morning MorganS . thanks for the reply , fair question; Have been so annoyed these past couple of weeks , decided to 'wipe the slate clean', all traces of Arduino etc , and start afresh. ! One thing crossed my mind last night, , there was a recent auto 'Win 10 update' - had minor problems before with some 'so called updates' and it made me wonder why my Arduino was recognised initially, ( April ) but not now..!!?
Hi matlogue, thanks for the input. Yes, checked contrast , on the I2C display (several times !) All 'squares clear, no 'text' , I was made aware that an address was needed, ( I suppose I am one of those ultra naive 'beginners) As for giving myself an hour of 'tooling around'and then putting it aside,? Yeah , I think I've done that enough times . Now I'm beginning to eye the 'lump hammer'