TFT35 Screen not communicating with SKR Mini E3 V3

Filament 3D Printer Technical Help
1

So I’ll try to give all the relevant info that I know, just ask if I missed any needed info.

I have an SKR Mini E3 V3 main board. I bought BTT TFT35 V3.0 screen to replace the LCD. I expected it (evidently incorrectly) to be fairly straightforward, what with both being BTT products.

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I get a No Printer Attached! error when powering it on. I verified that both the printer main board and the screen were set to a baud rate 115200.

The 5 pin JST cable I have tried in both of the 5 pin plugs, but I think(please correct me if I’m wrong) that the bottom one is the correct one. The other end of said cable that goes to the main board, that has a 1 pin connector and a 4 pin connector, I have tried in all four possible configuration on the 5 pin TFT pin set on the main board. I also initially tried all four configurations on the SWD 5 pin set before I saw the TFT labeled set.

I downloaded the firmware folders from GitHub and flashed the "BIGTREE_GD_TFT35_V3.0.27.x.bin file along with the config file and the font and bmp folders to go with the hybrid red theme while I was at it. It booted up fine, and did the whole firmware flashing process, and then opened up like it should, but still had the error.

I also tried following the advice in the following attached picture, again, the firmware flash worked, but no fix. I tried crossing the TX an RX wires in case I got it wrong, but no dice.

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As far the main board firmware goes, I use the custom compiler website here. Firmware Builder - Marlin Firmware Service According to the guy that runs that service, he has tested the board and screen combination I am using, and it works, so the main board firmware shouldn’t be the issue .:person_shrugging:

I really hope someone here can shed some light on the whole issue, because I am running out of ideas and patience with this. Thanks!

2

Are you trying to use it in emulated mode or TFT Mode ?

Is this the screen you have ?

3

Yes, that’s the one. It boots up in TFT mode, and I have no use for the emulated mode anyway. That’s why I bought a TFT screen after all. :grinning:

4

And did you build your marlin from source ? If so can you post your configuration.h ?

5

As I said in my original post, no, I used a custom firmware compiling service on linked website I have been using the firmware for close to a year. According to the guy that runs the service, the firmware is compatible with the screen.I have tried multiple times to compile my own firmware in the past, but I have run into technical difficulties that I can not find a way around every time, no matter how much research I do. Not worth the time and stress to try that again any time soon.

6

Well, I will be doing some communication with the guy who runs the firmware compiling service. Hopefully we can get things figured out The firmware appears to be the problem after all. I tried plugging the screen into another SKR MINI E3 V3 that still has BTT’s stock firmware; it connected with no trouble. I have one more E3 V3 board running identical custom compiled firmware. I’m going to try the screen on that board as well in order to (mostly) rule out the possibility of a defective main board. Otherwise, the issue has to be the firmware.

7

Well, good news and bad news. Good news, problem solved. I tried the screen on my other E3 V3 main board running custom compiled firmware, and it connected no trouble. Bad news, I’ll need to buy a new board if I want that one printer to have a TFT display.

8

Did you try flashing that same custom firmware on the other board ?

9

Not at the time no. The firmware is identical anyway other than a few details like bed dimensions. I did flash the firmware I wanted to the new board yesterday after diagnosing the issue, and it connected fine. I’m currently working with a CRTouch not working correctly. I’m fairly sure it’s a wiring issue, because I’ve tried another CRTouch from another printer that I know works, and it behaved the same. I’ve tried quite a few firmware configurations too. It’s a manually extended harness, so I suspect that doing some continuity and resistance testing will shed some light on that issue.