[BUG] BTT TFT35 E3 and MKS GEN L V1.0

[BlackRiverCoder]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

Hello, I just got BTT TFT35 E3 V3.0.1 and wanted to use it, but I also have OctoPrint server connected to main board and this 2 cannot work together. I wanted to set SERIAL_PORT_2 for TFT display to communicate by TX and RX in AUX-1 port in MKS GEN L V1.0, but I get error when compiling: #error "Serial Port 1 pin D18 and/or D19 conflicts with another pin on the board.", which are pins for Z endstop. I tried PORT 1, 2, 3, but still same error, just another pin numbers.

Is this wrong board pin configuration in Marlin?

Thanks
configurations.zip

Bug Timeline

When connected BTT TFT35

Expected behavior

OoctoPrint to run on default -1 or 0 PORT (USB) and BTT TFT35 to use TX and RX (port 1, 2 or 3) , so they can work both. (set temp on display or in octoprint)

Actual behavior

Can't do anything by OctoPrint, only by BTT TFT35

Steps to Reproduce

No response

Version of Marlin Firmware

2.1.2.5

Printer model

KRYAL Cube

Electronics

MKS GEN L V1.0

LCD/Controller

BTT TFT35 E3 V3.0.1 (GD version)

Other add-ons

No response

Bed Leveling

ABL Bilinear mesh

Your Slicer

None

Host Software

OctoPrint

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

No response

[ellensp]

The uart pins on a atmega2560 are fixed ie you cannot move them to other pins
UART 0 on pins 0 (RX) and 1 (TX),
UART 1 on pins 19 (RX) and 18 (TX)
UART 2 on pins 17 (RX) and 16 (TX)
UART 3 on pins 15 (RX) and 14 (TX)
so to use those you need to disable what ever is currently using the required pins

UART 0 pins 0 and 1 are on aux-1, these are connected to the usb to serial chip for usb
UART 1 pins 18 and 19 by default are z-min and z-max, so you would need to move the endstops elsewhere.
UART 2 pins 16 and 17 are on exp1, so conflict with the REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
UART 3 pins 14 and 15 by default are y-min and y-max, so to use these you would need to move the endstops else where.

-1 is not a valid option on this board

This is not a bug, these errors are deliberate to stop you setting impossible settings
These are limitations of your default hardware setting

[ellensp]

In your Config you have

#define Y_HOME_DIR +1
#define Z_HOME_DIR -1

You can easily move your endstops to a new plug.

You want to use uart 1

then physically move Z_MIN to Y_MIN plug and add the following to your Configuration.h

#define Z_MIN_PIN 14 // use Y_MIN plug
#define Y_MIN_PIN -1 // disabled

this will free up uart 1 and allow #define SERIAL_PORT_2 1

[ellensp]

you also have #define USE_ZMAX_PLUG
But what is plugged in there?
If its not used, disable this define
If it is used, you need to move it to another pin.

[BlackRiverCoder]

Hi, many thanks, that works :)

Have a nice day