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Anne_Carlill
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I can't get a SerLCD display that has 3V3 logic and uses I2C

Fri May 07, 2021 2:38 pm

DazzF wrote: ↑
Sun Jan 31, 2021 10:46 am
My suggestion would be to create a subforum off Raspberry Pi Pico call new to micro-controllers to allow people to ask very beginner type question and have a FAQ sticky at the top.
I like this idea but can't see that it has happened. I need a Beginner subforum under the Raspberry Pi Pico forum. Like some other people, I am really enjoying using the Pico but I'm a beginner. Mercifully, the book, 'Getting started with Micropython ...Pico' is very clear and I am learning a lot about basic electronics.

Now I am stuck because I can't get a SerLCD display that has 3V3 logic and uses I2C. I want to be able to read the temperature in text from a headless Pico arrangement. The display mentioned, in the book, seems unavailable. I've looked under the SerLCD posts in here but had no luck. Can someone help?

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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Fri May 07, 2021 4:14 pm

Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm
I want to be able to read the temperature in text from a headless Pico arrangement. The display mentioned, in the book, seems unavailable. I've looked under the SerLCD posts in here but had no luck. Can someone help?
I can't really help other than suggest you re-post your request as new thread where it might get more attention.
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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 10:18 am

lurk101 wrote:
Fri May 07, 2021 4:14 pm
I can't really help other than suggest you re-post your request as new thread where it might get more attention.
I am guessing this is that new thread, the post having been moved by mods, broken out of some other thread without any note that this was done ?

The up-arrow link in the quote in the OP doesn't work so it is hard to trace back, but I recall having seen the OP's post in another thread. I thought there were more responses to that than are here.

Added : The link to DazzF's post looks like it should be this one from the "Constructive Criticism" thread - viewtopic.php?p=1809056#p1809056 - That thread now has no posts since 2nd February.
Last edited by hippy on Sat May 08, 2021 11:26 am, edited 1 time in total.

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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 10:57 am

Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm

Now I am stuck because I can't get a SerLCD display that has 3V3 logic and uses I2C. I want to be able to read the temperature in text from a headless Pico arrangement. The display mentioned, in the book, seems unavailable. I've looked under the SerLCD posts in here but had no luck. Can someone help?

I think a change of Title for this new stand-alone thread would help clarify the substantive question...




Regarding your search for a display -

I don't have one, so can't speak from experience, but this might be what you are looking for? https://coolcomponents.co.uk/products/1 ... text-qwiic

(It is a UK online outfit with a fairly human-looking Contact Us page, even a UK landline number, so maybe you could seek reassurance from them directly?) https://coolcomponents.co.uk/pages/contact-us




The product they are selling seems to be the one advertised by Sparkfun (mentioned in the Guide) here - https://www.sparkfun.com/products/16397, and CoolComponents was located by using the 'Find a Retailer' link on that page.

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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 11:09 am

Not sure a beginners subforum would result in any more help being forthcoming. From our (RPI(T)) point of view, which forum a question is in doesn't really affect whether we answer it or not. I would assume the same for most people.

So just ask your questions in the appropriate place, if anyone knows the answer, hopefully it will be forthcoming.
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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 11:57 am

Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm
I am stuck because I can't get a SerLCD display that has 3V3 logic and uses I2C. I want to be able to read the temperature in text from a headless Pico arrangement. The display mentioned, in the book, seems unavailable. I've looked under the SerLCD posts in here but had no luck. Can someone help?
That "SerLCD" does seem to be the Sparkfun product B.Goode linked to which appears to be available - https://www.sparkfun.com/products/16397

That seems a nice display but is quite expensive. The Pico should be compatible with any I2C "backpack" display rated for 3V3 operation. Code used to drive those may differ from what's provided but should be easy enough to figure out and people can help with that.

If you are developing a standalone temperature display then an OLED display will be ideal. It might even be worth considering an OLED graphics display like the SSD1306 and similar. There is code for that and you can then add temperature graphs and icons as you become more proficient in programming.

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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 12:01 pm

Yes, this was a split off because it was hijacking with a different topic.

Now that is clear I will soon delete this thread, and I suggest that anne posts a new question, so I can delete this one as a (partial) duplicate.

If you are still asking for a new pico/beginners forum, then I would not waste your time with that, its unlikely such a forum will be created unless we sense a very large demand for it.
but that is just my expectation, and what do I know....? :mrgreen:

If you want answer to your question "SerLCD display that has 3V3 logic and uses I2C", then ask in a new thread!

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Re: I need a Beginner subforum under the Raspberry Pi Pico forum

Sat May 08, 2021 2:28 pm

mahjongg wrote:
Sat May 08, 2021 12:01 pm
Yes, this was a split off because it was hijacking with a different topic.

Now that is clear I will soon delete this thread, and I suggest that anne posts a new question, so I can delete this one as a (partial) duplicate.
Thanks for the warning. I will copy my reply so I don't have to type it in again when it gets deleted.
lurk101 wrote:
Fri May 07, 2021 4:14 pm
Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm
I want to be able to read the temperature in text from a headless Pico arrangement. The display mentioned, in the book, seems unavailable. I've looked under the SerLCD posts in here but had no luck. Can someone help?
I can't really help other than suggest you re-post your request as new thread where it might get more attention.
That line wasn't in bold earlier, nor in the original. Silent editings of posts feels rather disconcerting.

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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Sat May 08, 2021 2:39 pm

Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm
Now I am stuck because I can't get a SerLCD display that has 3V3 logic and uses I2C.
They're two different things:
  • a SerLCD is a SparkFun product that connects via UART. They have a microcontroller that does the clever stuff, so all you need to to is write() or print() text to the SerLCD's serial port and it displays. They are more expensive than generic text displays, but much easier to use.
  • a 3.3V I²C backpack for a HD44780 text display (1602, 2002, etc). The hard part is finding the 3.3V: 5V ones are everywhere and just don't work with the Pico. I've got one supposedly 3.3V unit that seems to be 5V only, so that one also doesn't work with the Pico. Newer displays that explicitly say 3.3 V power and logic should work.
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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Sat May 08, 2021 2:56 pm

scruss wrote:
Sat May 08, 2021 2:39 pm
Anne_Carlill wrote:
Fri May 07, 2021 2:38 pm
Now I am stuck because I can't get a SerLCD display that has 3V3 logic and uses I2C.
They're two different things:

The product description from Sparkfun at the link already Cited appears to say otherwise:
This display can now communicate in three different ways: serial, I2C, and SPI.
and
Since the SerLCD is a 3.3V device, please make sure you convert to 3.3V logic depending on your chosen microcontroller or single board computer

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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Sat May 08, 2021 6:36 pm

B.Goode wrote:
Sat May 08, 2021 2:56 pm
The product description from Sparkfun at the link already Cited appears to say otherwise:
This display can now communicate in three different ways: serial, I2C, and SPI.
Ah; the I²C and SPI bits are a new thing. I mean, you could spend more on a SerLCD and use it for synchronous serial, but that's kind of expensive. SparkFun still sell their original SerLCD — Serial Enabled 16x2 LCD - White on Black 5V — which is very 5V and very UART serial only.
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Anne_Carlill
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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Mon May 10, 2021 9:59 am

We think we've solved this, that is I've had a lot of help from Mike Horne @recantha and Sukkin at https://www.skpang.co.uk/ . A number of people sell the Sparkfun SerLCD display with a Qwiic connector. It has I2C which is what I need.

Now I couldn't see how to connect this to a breadboard. However, I have found a cable here: https://shop.pimoroni.com/products/jst- ... 0609846355 (It mentions Dupont headers which I guess are just those male pins you get on the end of jumper wires.)

This cable is available from a few Pi sellers and it should do the trick. What I still haven't been able to find out is if these Qwiic connectors have a male end and others have a female end. Does anyone know about this? I've been caught out by buying the wrong end-connector before.

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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Mon May 10, 2021 10:09 am

Anne_Carlill wrote:
Mon May 10, 2021 9:59 am
This cable is available from a few Pi sellers and it should do the trick. What I still haven't been able to find out is if these Qwiic connectors have a male end and others have a female end. Does anyone know about this? I've been caught out by buying the wrong end-connector before.
The cables I have seen for the Quiic boards have all had female connectors on both ends of the cables. The boards they connect to all have male sockets.
Sparkfun do make cables with quiic connectors on one side and dupont female connectors on the other side to make them "Pi friendly"
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Anne_Carlill
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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Mon May 10, 2021 10:17 am

scotty101 wrote:

The cables I have seen for the Quiic boards have all had female connectors on both ends of the cables. The boards they connect to all have male sockets.
Sparkfun do make cables with quiic connectors on one side and dupont female connectors on the other side to make them "Pi friendly"
This is a really useful explanation, thanks.

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Re: I can't get a SerLCD display that has 3V3 logic and uses I2C

Mon May 10, 2021 12:29 pm

well it seems your question is answered, so I expect you won't post a new thread.

I could try to cleanup the thread, but why??? :mrgreen:


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