Using EVE2-70A-TPN with STM32 NUCLEO-F446ZE

[Tuomas]

Hi all,

I've been trying to get the EVE2-70A-TPN display to work with STM32 NUCLEO-F446ZE board. I followed the instructions for the basic demo code in viewtopic.php?f=45&t=6860 and with slight modifications to pin mappings etc. I was able to successfully run it on the NUCLEO-F446ZE. However, when I try to modify the example code to print numbers using Cmd_Number, it doesn't work. For example if I replace this line

Code: Select all

Cmd_Text(Display_Width() / 2, Display_Height() / 2, 30, OPT_CENTER, " MATRIX         ORBITAL"); //Write text in the center of the screen

with this

Code: Select all

Cmd_Number(Display_Width() / 2, Display_Height() / 2, 30, 0, 123);

nothing is printed on the screen. Any idea what could cause this? Am I doing something wrong?

Best regards,
Tuomas

[Raquel]

Hello Tuomas,

Thank you for posting on the forum.

I apologize for the error on EVE library. It is now fixed.
CMD_NUMBER used by Cmd_Number() was incorrectly defined:
#define CMD_NUMBER 0xFFFFFF38 was changed to:
#define CMD_NUMBER 0xFFFFFF2E

Thank you,
Raquel

[Henry]

Please make sure you use the main EVE Library, this one is the one that is actively updated

https://github.com/MatrixOrbital/EVE2-Library

[Tuomas]

Thank you!

It seems I have another question. I fear I might have broken the display. It doesn't work anymore with the Nucleo board like it did before. When I try the Eve Bitmap Viewer, this happens: https://youtu.be/YBsLC2-jmbE

So as seen on the video, it tries to display the "Matrix Orbital" text, but then it goes completely white, and it doesn't display any images I drop to the Viewer.

Before this problem appeared, I did make a mistake with the FFC cables. I had the wrong one (Same side contacts vs. Opposite side contacts) connected to the display for a while with VCC on, so the signals were mirrored (1<->20, 2<->19 etc.). Because of this there was a short circuit between VCC and GND on my PCB (through BLGND pins 19 and 20). The other VCC from my PCB was then connected to MOSI on the EVE2 board, which I think shouldn't cause any issues. I hoped this mistake wouldn't have caused anything to the display. Now I am not sure anymore.

Can you make any conclusions based on this information? Is it broken? I really appreciate if you could give me some advice with this.

[Raquel]

Hello Tuomas,

Sorry to hear about the connection mishap.
When you connected the display using the wrong FFC cable (contacts on same side), I imagine R1 and R2 on the EVE2 are populated?
If that is the case, then yes 3.3V rail is shorted on the source and on the EVE display - and sounded like your board took the damage.
The display may have survived the short, but I would not be trusting it very much.
If you have another FFC cable you can use (contacts on opposite sides) please give it a try.

Let me know how it turns out.