I2C LCD lib

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Hans van Veldhuizen

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Feb 3, 2025, 11:35:43 AMFeb 3
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Hi all,
A while ago I bought a few 16x2 LCDs and they came with I2C adapters that I haven't used yet. Is there already a sample program for this kind of thing?
Greetings
Hans

Rob CJ

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Feb 3, 2025, 12:53:21 PMFeb 3
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Hi Hans,

I am missing information here. Which I2C adapters do you mean?

Kind regards,

Rob

Van: jal...@googlegroups.com <jal...@googlegroups.com> namens Hans van Veldhuizen <hanz...@zeelandnet.nl>
Verzonden: maandag 3 februari 2025 17:35
Aan: jallib <jal...@googlegroups.com>
Onderwerp: [jallib] I2C LCD lib
 
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pinhe...@gmail.com

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Feb 3, 2025, 1:00:41 PMFeb 3
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I guess you are talking about the az-delivery combo.

They have an ebook online for free where you will find all the commands




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pinhe...@gmail.com

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Feb 3, 2025, 1:02:14 PMFeb 3
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Le 3 févr. 2025, à 18:53, Rob CJ <rob...@hotmail.com> a écrit:

Hans van Veldhuizen

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Feb 3, 2025, 1:27:50 PMFeb 3
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Hi Pinhead, it is not from AZ but it looks identical. Great again somthing to try.
Thanks 
Hans

Op maandag 3 februari 2025 om 19:02:14 UTC+1 schreef pinhe...@gmail.com:

Rob CJ

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Feb 3, 2025, 1:48:28 PMFeb 3
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Hi Hans,

There is a JAL library for the HD44780. Not sure if you are looking for that.

Kind regards,

Rob

Verzonden: maandag 3 februari 2025 19:27
Aan: jallib <jal...@googlegroups.com>
Onderwerp: Re: [jallib] I2C LCD lib
 

Hans van Veldhuizen

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Feb 3, 2025, 3:49:16 PMFeb 3
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Hllo Rob,
Do you mean ; lcd_hd44780_pcf8574. jal .  The pcf8574 look different..
regards
Hans

Op maandag 3 februari 2025 om 19:48:28 UTC+1 schreef Rob CJ:

Rob CJ

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Feb 4, 2025, 1:01:11 PMFeb 4
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Hi Hans,

I do not know what you mean. I see in Jallib several libraries for the HD44780, some for use with the display directly and one using a PCF8574. If the type number is the same, the library should work (I assume).

If you have enough pins available on your PIC, you could use the one that interfaces directly with the display by a 4-bit bus or 8-bit bus.

Kind regards,

Rob

Verzonden: maandag 3 februari 2025 21:49

Hans van Veldhuizen

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Feb 4, 2025, 1:23:08 PMFeb 4
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Hello Rob,
It is not about the HD44780 on the well-known 6-pin connection. It is about an interface that you can stick on such an LCD and then control the thing with I2C, (so only two connections instead of 6). The PCF8574 is a different thing. The link that Pinhead indicated (to AZ is about such an interface.)

https://www.az-delivery.de/products/lcd-display-16x2-blau-und-i2c-set-kostenfreies-e-book
greetings
Hans

Op dinsdag 4 februari 2025 om 19:01:11 UTC+1 schreef Rob CJ:

Pinhead

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Feb 4, 2025, 4:32:20 PMFeb 4
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Hi Hans,

The only "piggyback" that I know of for alphanumeric LCD's contain an I2C-to-8bit converter, most of the time, an PCF8574

If this is not the part that is on yours, please mention it.

For the rest, the trick is "only" to send on I²C the commands that are documented in the HD44780 datasheet.

Therefore, I think you should give a try to the lcd_hd44780_PCF8574.jal library.

If the chip on your adapter is another chip, check also what is the I2C adress to be used (the library used adress 0x27, hardcoded)

Hope this helps

David

Le 04-02-25 à 19:23, Hans van Veldhuizen a écrit :

Hans van Veldhuizen

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Feb 5, 2025, 2:56:37 AMFeb 5
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Hi Pinhead,
I have followed your advice on a 16F877a (from the sample 's) and indeed it works perfect. I
Great, Thanks
hans

Op dinsdag 4 februari 2025 om 22:32:20 UTC+1 schreef Pinhead:
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