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Forum : Digole Serial Display : 12864 LCD/OLED module :

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LCD 12864 display no chars


i have an lcd 12864 module v2.0 for arduino and your backpack.

I try using it with I2C and shorted the I2C / SPI jumper. The display is found by I2C scanner at address 0x27.

Tried it with some of the example sketches but the display shows nothing.

The only sketch seems to work is the power management. The display turns off and on again.

Tried a shorted own code:

#define _Digole_Serial_I2C_
#include <DigoleSerial.h>

//--------I2C setup
#if defined(_Digole_Serial_I2C_)
#include <Wire.h>
DigoleSerialDisp mydisp(&Wire,'\x27');

void setup() {
    /*----------for text LCD adapter and graphic LCD adapter ------------*/
//    mydisp.setColor(255);
    mydisp.clearScreen();         //Clear screen
//    mydisp.displayConfig(1);    //set config display ON, 0=off
//    mydisp.enableCursor();        //disable cursor, enable cursore use: enableCursor();


void loop() {

But still nothing. Any ideas. I am something missing ?

Thank you vervy much.






RE:LCD 12864 display no chars

The code:


might be out of range of screen, try to reduce the Col/Row, try this:




RE:LCD 12864 display no chars

Thanks for your answer but doesn't change anything.

I soldered the backpack directly to the display. Isn't that correct ?

Tried to upload a picture but that doesn't work neither.

RE:LCD 12864 display no chars

What GLCD panel you used? This adapter can detect many of GLCD with ST7920, KS0108 and ST7565 (SPI) controller, but may also need manual config for some special GLCD.

If the adapter success detected the GLCD controller, it will display a welcome screen on GLCD when power on, other wise, the GLCD will keep in blank, and only backlight was on.

RE:LCD 12864 display no chars

12864B V 2.0 ST7920

RE:LCD 12864 display no chars

 No, I meant the GLCD you used, because I found you bought our Universal GLCD adapter.

RE:LCD 12864 display no chars

I bought this one



RE:LCD 12864 display no chars

Did you short the P jumer on JP2 which on your GLCD? if not, you need to connect the PSB pin to Vcc.

RE:LCD 12864 display no chars

I checked the pinout on our adapter and your GLCD, you can solder the adapter to GLCD directly, but you need short the "P/S" jumper (JP2) at "P", that will let your GLCD work at parallel mode, if you can't access the JP2 now, you also can connect the PSB pin to VCC (+5V).

RE:LCD 12864 display no chars

Thank you very much for your help.

I will try that out.

RE:LCD 12864 display no chars


sorry for answering late but I hadn't enough time.

After short the "P/S" jumper (JP2) at "P" the display seem to work but the

the text on the display is shown very weak. I played around with the contrast

but it doesn't seem to help.

I use the old libraries because I get compiling errors at every example sketch

of the new librarie:

C:\Users\trinoo\AppData\Local\Temp\ccbfjFFh.ltrans0.ltrans.o: In function `DigoleSerialDisp::read1()':

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:93: undefined reference to `TwoWire::requestFrom(int, int)'

C:\Users\trinoo\AppData\Local\Temp\ccbfjFFh.ltrans0.ltrans.o: In function `DigoleSerialDisp::write(unsigned char)':

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:83: undefined reference to `TwoWire::beginTransmission(unsigned char)'

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:85: undefined reference to `TwoWire::endTransmission()'

C:\Users\trinoo\AppData\Local\Temp\ccbfjFFh.ltrans0.ltrans.o: In function `begin':

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:73: undefined reference to `TwoWire::begin()'

C:\Users\trinoo\AppData\Local\Temp\ccbfjFFh.ltrans0.ltrans.o: In function `_GLOBAL__sub_I_mydisp':

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:78: undefined reference to `Wire'

C:\Progging\Arduino\libraries\DigoleSerial/DigoleSerial.h:78: undefined reference to `Wire'

collect2.exe: error: ld returned 1 exit status

exit status 1

The Wire librarie is installed.

I can work with the old librarie. That's no problem but how can I make the text more readable?

Thank you.



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