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RepRap Discount Full Graphics Display for Melzi

Posted by ajacks 
RepRap Discount Full Graphics Display for Melzi
April 24, 2020 02:17AM
I recently got a cheap RepRap Discount Full Graphics Display for my Melzi that I'm trying to get to work with 1.1.9. I was able to get the display to work with Repetier, but I'm having trouble getting it to work with Marlin. I had to change some of the pin definitions in pins_SANGUINOLOLU_11 to match how I wired the display to the board. I know this pin combination works, as it is the same as I used for Repetier.

#define LCD_PINS_RS 29
#define LCD_PINS_ENABLE 16
#define LCD_PINS_D4 11
#define BEEPER_PIN 27
#define BTN_ENC 10
#define LCD_SDSS 28
#define BTN_EN1 17
#define BTN_EN2 30

The display lights up and something is displayed, but it looks like the screen width is not correct so everything is garbled (see photo). I really like the display, and it seems that Marlin uses less flash RAM than Repetier, so I am really interested in getting this to work. Any help getting this display to work would be much appreciated.
Attachments:
open | download - Configuration.h (70.3 KB)
open | download - pins_MELZI.h (1003 bytes)
open | download - Marlin2.JPG (73.1 KB)
Re: RepRap Discount Full Graphics Display for Melzi
April 24, 2020 06:40AM
This is just timing..

Marlin pushes the speed of the display to the maximum.

Sadly some LCD's can't do it.

add some delays eg
#define ST7920_DELAY_1 DELAY_NS(125)
#define ST7920_DELAY_2 DELAY_NS(125)
#define ST7920_DELAY_3 DELAY_NS(125)

you may need other values. I've seen anything from 48 to 715 used... depends on your hardware,
Re: RepRap Discount Full Graphics Display for Melzi
April 24, 2020 09:50PM
Yep, that did it. Thanks. Is there any benefit in tuning the delay value?
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