Initialization problems display ST7565R

[Pichuqy_1]

Hello everyone!

I've been trying to initialize the following display for days, working with different codes and tutorials and I've just about to give it up. . I don't know if the initialization code is written in the correct way as well as the glcd_command and glcd_data functions. Can you help me to understand what the problem is, please?

The display is the following:

URL https://es.aliexpress.com/item/1005001621784395.html?spm=a2g0s.9042311.0.0.56fb63c0DvXFmX /url

The datasheet:

URL https://pdf1.alldatasheet.com/datasheet-pdf/view/326163/SITRONIX/ST7565R.html /url

I'm using the following hardware:



For the initialization function "glcd_init()" I use from datasheet page 51:



When it comes to SPI configuration, I use the following from datasheet page 24:



And the code is:

Main

[PCM programmer]

Look closely at your schematic, at pins D0 and D1 on the PIC.
Just to the left of the PIC symbol, you have a dot, connecting
the D0 and D1 lines together. This means CLK and SI are shorted.
That dot should be removed.

[Ttelmah]

Also, why not just use the CCS SPI code.
Much faster, less to go wrong. The #use spi command offers a software spi
in just one direction like you need here. Though I cannot see a specification
for a minimum spi frequency, some chips do have this hidden inside. You
are clocking the SPI so slowly, that I wonder if this could be a problem....

[Pichuqy_1]

Pcm Programmer: You are right, but this is just a schematic mistake. In the real board it is correct. Thanks for make me know.

Ttelmah: I know you are right. The problem is that I don't how to configure it yet. On the other hand, I'm not sure what kind of SPI mode the display use as well as the frequency. The datasheet doesn't specify anything about it as you mention.

What is the #USE SPI command you recommend in this case? Can I choose whichever pin I want? I'll make a try, I really want to turn this display on.

Thanks so much!

Emilio

[PCM programmer]

[Pichuqy_1]

Thanks for your reply. What do you think about the clock's initial state? According to the SPI diagram, it should be initialized to a high level too, isn't it?

[Pichuqy_1]

This is the clock and data diagram that I got in the LCD when the program executes the code 0b10100011. I think it is ok.

[PCM programmer]

I'm not sure how you get that timing diagram, because your posted
code uses SPI Mode 0, but the timing diagram shows SPI Mode 3.
SPI Mode 0 has the clock idle low, and Mode 3 has it idle high.

Those two modes are usually interchangeable for chips that use
either one.

[Pichuqy_1]

The reason is that I've tried with the two SPI mode, 1 and 3, in order to make it works and maybe I took the picture and then I change the code.
So, one of my doubts here is: according to the datasheet this display uses the SPI mode 3, right?

Thanks

[PCM programmer]

That is correct.

[Pichuqy_1]

Hello everybody!

Unfortunately, I've not found a way to turn on the display. I've been struggling with it for weeks, but I am not able to make it work. I'd like to share with you the changes I made so as to find together the mistake in my code.

1) First, I changed the XT 4 MHz for 16 MHz. I thought that maybe with 4 MHz the clock wasn't fast enough. Even though the communication is working perfectly, the LCD doesn't work. The clock is running at 13 KHz. See the picture below.



2) Second, I'm using the #use spi mode instead of the code one.

3) Third, I've been testing two different initialization ways, one at a time of course. I'll share it below, please let me know if you notice something wrong. I'm losing my cool with this program.



This is the main.c file

[PCM programmer]

I translated the init code from these two web pages.
Try it and see if it works.
https://github.com/adafruit/ST7565-LCD/blob/master/c/stlcd.c
https://github.com/adafruit/ST7565-LCD/blob/master/c/stlcd.h

The code below uses your pin numbers. But it's doing the reset
and the Chip Select differently than your code. Try it.

[temtronic]

I'm wondering if you should put a

delay_ms(500);

in main() before you try to access the LCD

This has always been required for text LCDs as it gives time for the LCD module to properly powerup. I downloaded a version of the GLCD datasheet but didn't see a spec on 'powerup delay before accessing the LCD'.
If you put the code it, try it and it still doesn't work, you've eliminated it as a possible cause.

Are you 100% sure the PIC and LCD are connected properly ?

[Ttelmah]

To use standard SPI, select MODE=3. This is what the display is doing.
Commands would then become:

[Pichuqy_1]

Thanks for your reply. The display is working perfectly right now!!