st7789h2 TFT LCD module

[TFT LCD ST7789H2]

 

HI sir,

My self-Mahesh firmware engineer at datashrubs solutions

Currently I am working with 1.54 inch display module(st7789h2),This module is configured with four wire SPI.

I am facing some issues

1, Pixel writing is very slow.

2, Not able to control the brightness.

3, I am able to write only full image(240*240)

Pixel writing is very slow:

I am able to display the test and image, however writing  speed is very slow ,to write full image (240 *240) pixel its taking around 4min. we tried to change frame rate value (00 to FF )in C6h register ,still pixel writing  speed  remains same. Please find the attached video file you can see the how the pixel writing.

Kindly let me know how to increase the pixel speed.

 

Not able to control the brightness:

We are setting the BCTRL bit to enable the brightness control blank in 53h register, Display control register (51h) DBV0-7 value we tried to change it from min to max ,however  brightness remains same. Any other register need to be set.

 

I am able to write only full image(240*240):

To get bitmapping image data(16bit) I am using LCD image converter tool.  When we tried to write full image( 240*240) its displaying properly,

but when we tried to write 100 *100 Pixel it’s not displaying as expected.

 

[Joel Bodenmann]

Hello & welcome to the µGFX community.

Given that the library currently doesn't ship with a GDISP driver for the ST7789 I assume that you wrote your own.
We'll try to address your issues as best as we can:

• Speed: Make sure that your driver is setup correctly and that your host's SPI is configured to run at a decent speed. Check the corresponding datasheet(s) to determine the maximum allowed bus frequency that your physical driver and display module can handle.
• Brightness: Not every display module uses features built into the physical controller for screen brightness control. Often you get a simple set of LEDs with which you can control the brightness via PWM. Check whether this is the case in your scenario. If so, changing any of the physical display driver configuration registers won't have any effect on the display brightness. You can setup a PWM peripheral in your GDISP driver's board file in order to still be able to use gdispSetBacklight() to control the brightness.
• Full image: I'm not sure what you mean by this. However, this sounds again like an issue with your GDISP driver. I do not know which "LCD image converter tool" you're talking about. Image formats supported by µGFX are listed here: https://wiki.ugfx.io/index.php/Images

It's difficult to help without being able to review the driver. If you're unable to share the driver publicly, you can get in touch with us for paid support.