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LDmicro Forum - LCD i2c circuit diagram

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LCD i2c circuit diagram (by Ahmad sakr )
Dear sir
To jose
I received my pcf8475. I want to connect it to my lcd
Like the picture in attachment and connecting
Scl to atmega 8 pin 28
Sda to atmega 8 pin 27
Is the blue variable resistance for controlling lcd light
Tue Jun 9 2020, 10:33:16, download attachment i2c.PNG
(no subject) (by José)

Yes it is for backlight control.

Then you'll have to configure your I2C as explained in attached file.

JG
Tue Jun 9 2020, 13:19:37, download attachment LcdI2cLib-en.txt
(no subject) (by Ahmad sakr )
Thanks for your reply
About the connection schematic is it true?
Tue Jun 9 2020, 17:18:03
(no subject) (by Ahmad sakr )
Dear sir
Could you please help me how to know i2c address (0x27) to be modified in the library
Thanks
Tue Jun 23 2020, 16:59:26
(no subject) (by José)

Post a photo of your I2c module ; there are generally 3 soldering jumpers which determine the address ; in most common cases it is by default 0x20 (3x0ff) or 0x27 (3xOn).

José
Wed Jun 24 2020, 03:18:12
(no subject) (by Ahmad sakr )
The photo in attachment
Wed Jun 24 2020, 10:05:02, download attachment 20200624_160241.jpg
(no subject) (by José)
A0-A1-A2 are not soldered => I2C address must be 0x20
Try it !
Wed Jun 24 2020, 15:52:35
(no subject) (by Ahmad sakr )
I tried 0x27 work good
Thanks for your great work
Thu Jun 25 2020, 06:48:44
(no subject) (by José)
OK ; that's fine !
Fri Jun 26 2020, 02:31:30
(no subject) (by Duy Phuong)
Hi José
I have a problem with the I2C LCD address, I have 4 LCD using I2C have 4 different addresses as 0x27, 0x26, 0x23, and 0x20, I already tested using one by one address but only 0x27 working, and another no. I had edited i2c library i2c.h and add some define row like this:
#define LCD_I2C_ADR 0x27 // a adapter selon afficheur (si utile)
#define LCD_I2C_ADR 0x26 // a adapter selon afficheur (si utile)
#define LCD_I2C_ADR 0x23 // a adapter selon afficheur (si utile)
#define LCD_I2C_ADR 0x20 // a adapter selon afficheur (si utile)
And changed adress in LD file but issue still happen. Can you help review and check?

Besides that, I can not run flash MCU.bat version 5.4.0.4, it only working at ver 5.3.1.0 for I2C function, can you check it again?
Wed Jul 8 2020, 06:33:18, download attachment i2c_lcd16x2.ld
(no subject) (by José)
Sorry, but I'm now in holidays and won't be able to help you for the time being...
Wed Jul 8 2020, 07:07:04
(no subject) (by Duy Phuong)
Thanks, José
I detected my problem caused by the C code not overwrite when I compile a new one, the problem was fixed by clear all old file every new compile.
However, the next issue is I can not control multi-address via I2C, do you have any example for this one?
Mon Jul 13 2020, 06:45:13
(no subject) (by José)
You can only use one I2C bus at a time (except on ARM) ; but on the bus you should normally be able to use several peripherals on different addresses
Mon Jul 20 2020, 13:48:38
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