Geeetech

Posted: **Wed Jul 28, 2021 6:06 am**

Hello Community,
I recently acquired an A20M with a dead controller board. Instead of replacing the outdated mega 2560 board I opted for a BTT Octopus V1.0 board. This way I can add dual Z's with independent drives for leveling, still keep the dual extruders, and have plenty of expansion room. I want to keep the original LCD for looks as I am going to be using esp3D via wifi most of the time. I got the board nicely installed and under power. Flashed it (Marlin 2.0) with the LCD Settings:

#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
#define ST7920_DELAY_1 DELAY_NS(125)
#define ST7920_DELAY_2 DELAY_NS(125)
#define ST7920_DELAY_3 DELAY_NS(125)

This is the LCD board:
https://www.geeetech.com/a20mt-lcd-scr ... 1178.html

I also got most of the LCD PINS reverse engineered but there is a few I just can't figure out:

Code: Select all

GEETECH A20M GT2560 V4.1 12864 LCD PINOUT
BOARD: DZ12864KD03  PCB V1.0

                           -------
                       5V | 1   2 | GND
             LCD_EN - PC1 | 3   4 | LCD_D6 - PE3
                ??? - PD1 | 5   6 | GND - OR PULLED LOW
            BTN_EN1 - PH1 | 7   8 | BTN_EN2 - PH0
            BTN_ENC - PD2 | 9  10 | GND - OR PULLED LOW
                    RESET | 11 12 | BEEPER - PD3
                           -------

At this point I just need to figure out LCD_D4, LCD_D5, and LCD_D7. Under power I just get blue screen, I can reset board and can hear beeper when I push the encoder button.
Any help on this would be super appreciated. Wish Geeetech published the schematics for the GT2560 V4.1 or this LCD board, ugh.

Posted: **Thu Jul 29, 2021 6:34 am**

So I actually found the schematic for the GT2560 V4.1 board on the A20M Geeetech download page (Why I didn't check that first is beyond me).
It says this is the pinout:

Code: Select all

                           -------
                       5V | 1   2 | GND
             LCD_D7 - PC1 | 3   4 | LCD_D6 - PE3
             LCD_D5 - PD0 | 5   6 | GND
             LCD_D4 - PH1 | 7   8 | LCD_EN - PH0
            BTN_ENC - PD2 | 9  10 | GND
                    RESET | 11 12 | BEEPER - PD3
                           -------

So I was close but what happened to BTN_EN1 and BTN_EN2???

I hooked it up accordingly the the Octopus but still get a blank blue screen....

Posted: **Thu Jul 29, 2021 12:08 pm**

I GOT IT!!!

Code: Select all

                           -------
                       5V | 1   2 | GND
             LCD_EN - PC1 | 3   4 | LCD_RS - PE3
             LCD_D4 - PD0 | 5   6 | GND
            BTN_EN2 - PH1 | 7   8 | BTN_EN1 - PH0
            BTN_ENC - PD2 | 9  10 | GND
                    RESET | 11 12 | BEEPER - PD3
                           -------

And in Marlin set:
#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
#define ST7920_DELAY_1 DELAY_NS(200)
#define ST7920_DELAY_2 DELAY_NS(200)
#define ST7920_DELAY_3 DELAY_NS(400)

Works Great Now!

Geeetech

GT2560 V4.1 12864 LCD PINOUT for BTT OCTOPUS V1.0

GT2560 V4.1 12864 LCD PINOUT for BTT OCTOPUS V1.0

Re: GT2560 V4.1 12864 LCD PINOUT for BTT OCTOPUS V1.0

Re: GT2560 V4.1 12864 LCD PINOUT for BTT OCTOPUS V1.0