about using ST008-U LCD

[Leogean]

Hi, hope you everything goes well.

I have a question about using the CT008-U LCD, with nrf52840. And I am going to use gfx class function to write text or draw a rectangle on this LCD. I see that in the example it is using

nrf_lcd_t nrf_lcd_ili9341

nrf_lcd_t nrf_lcd_st7735

But I do not find the corresponding "nrf_lcd_t" for my lcd instance. Do you think I can use gfx class combined with SPI. Though I still cannot find a way to define a lcd instance for CT008-U. Could you please give me a hint to it?

By the way, if I want to implement something like LCD touch screen, I can do this with SPI, right?

Thanks a lot for all the advice you give to me:D

[awneil]

Do you understand how to drive a bare LCD glass ?

If not, you would be better off using one of the driver chips such as ili9341 or st7735 - then you could use those libraries!

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/lib_gfx.html

[Leogean]

Thanks for your response and the link you share with me. 

Yeah actually, I have a project which originally writes in Javascript, and it uses SPI to connect the LCD board and using graphics class to display the LCD. But graphics class is so old for C language and it does not support 64bit Windows. So I am looking into gfx to replace graphics class. Also I guess with SPI, I am able to implement touch screen function, right?

Best regards.

[ovrebekk]

Hi 

Are you saying you already have a system for connecting to the CT008-U display that is working over SPI?

From what I could find online this appears to be a laptop display, which usually use more sophisticated (and harder to use) interfaces.  

Leogean said:

Also I guess with SPI, I am able to implement touch screen function, right?

This depends on what type of display you are using. 

Many display modules use one interface for the display, and a separate interface (such as I2C) for the touch screen functionality. 

Best regards
Torbjørn

[Leogean]

Hi,

Sorry for answering after such a long time. Hum.. I find that the controller of my LCD board is UC1608. I am trying to write the driver according to the datasheet for my LCD, but looks like it is a long way to go...

During this time, I came up with another idea. The LCD I am using is 240*120, I am thinking if I can use a frame buffer to store the image or text of one screen to a 240*120 matrix, and then upload the whole pixel matrix to the LCD through SPI. 

This method is implemented in the js code (as I said before, the project is originally implemented in js). The js code uses the graphics class function to draw graphics and write text to the 240*120 array, then upload this array to the LCD. However, the graphics function is not capable of C on Windows 64bit. I find that LCD class function (as the link below) might help me to do the similar thing as the graphics class function. Just it looks like I finally still need to work out an LCD driver. 

infocenter.nordicsemi.com/index.jsp

Do you think the frame buffer method might make it easier for me to use my LCD board? Is there an example code that includes the "lcd_display" (used to write the whole buffer to the LCD) and the use of "nrf_lcd_t" struct?

Thanks a lot for any advice you give to me. Please let me know if you find anything doesn't make sense. 

Best regards, Leo

[ovrebekk]

Hi Leo

I must admit I am a bit unsure what your hardware setup looks like. 

Are you running the LCD from a Windows based host PC, connected to the nRF52840 device in some way?

Can you provide some more details on how the nRF52840 is connected to the PC and to the display?

Do you have a link to this "graphics class" that you are referring to?

If I understand you correctly you got the LCD working using the old graphics class on a 32-bit Windows machine?

Best regards
Torbjørn

[Leogean]

Hi,

Thanks a lot for your response. The graphics class function I was talking about is 

https://www.espruino.com/Graphics

Also, I make some progress this morning. Because the LCD I am using has 15 pages and 240 columns. I create a 15*240 int8_t matrix and write 1 to all the pixels. I am able to get figures on the LCD screen in this way. So now the problem seems to change to how can we shape the values in the matrix (especially, when I want to write string).  As I mentioned, the graphics class function is able to help me write data to the matrix in different shapes (rectangle, line, string). But this class function is not capable of my current system. Do you think there is a substitute class function I can use?

Thanks again for your patience, and please let me know if more information is needed.

Best regards, Leo

[ovrebekk]

Hi Leo

Which board are you using? 
It is one of the standard Espruino boards?

For Espruino related question you probably want to check on their forums, since Espruino is not a Nordic product and is not supported by us directly. 

Best regards
Torbjørn