Teensy 4.1 and SERIAL_PORT_2 ERRORS

Hi all
before every one says WHY a teensy 4.1. just becasue i can.

but i made my own motherboard for my 3d printer with a teensy 4.1 and all so far seems to work great!
BUT when i try to enable #define SERIAL_PORT_2 1 and at the same time #define SERIAL_PORT 0
i get ALLOT of errors.

it only works when i disable //#define SERIAL_PORT_2 1 and change #define SERIAL_PORT 1
it all works great but i would love to have usb on serial port 0 and tft screen on serial port 1

can someone shed some light.

3d printer specs:
XYZ threaded rod TR8X8
XYZ mks servo42c
Extruder Revo hemera
Bltouch
heated bed
teensy4.1
Sidewinder X1 TFT
old Ender3 frame

"just because i can." ah but you can't, that is why your here...



Apply this diff.

This Compiles. But I don't have the hardware to test it

diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.cpp b/Marlin/src/HAL/TEENSY40_41/HAL.cpp
index 1d02ab8575..f6dae65f6e 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.cpp
@@ -42,6 +42,9 @@
 #if WITHIN(SERIAL_PORT, 0, 3)
   IMPLEMENT_SERIAL(SERIAL_PORT);
 #endif
+#ifdef SERIAL_PORT_2
+  #if WITHIN(SERIAL_PORT_2, 0, 3)
+   IMPLEMENT_SERIAL(SERIAL_PORT_2);
+  #endif
+#endif
 USBSerialType USBSerial(false, SerialUS;
 
 // ------------------------
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 84c5847677..5a0fb8e90b 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -94,6 +94,7 @@ extern USBSerialType USBSerial;
   #elif SERIAL_PORT_2 == -2
     #define MYSERIAL2 ethernet.telnetClient
   #elif WITHIN(SERIAL_PORT_2, 0, 8)
+    DECLARE_SERIAL(SERIAL_PORT_2);
     #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from 0 to 8, or -1 for Native USB, or -2 for Ethernet."

The above will probably work well enough for your situation, but here is a more substantial change

This should allows for SERIAL_PORT, SERIAL_PORT_2 and SERIAL_PORT_3 to be set to any port from -1 to 8

special serial over Ethernet -2 is still limited to SERIAL_PORT_2 only.

replace Marlin/src/HAL/TEENSY40_41/HAL.cpp with HAL.cpp
and Marlin/src/HAL/TEENSY40_41/HAL.h with HAL.h

But beyond compiling it, I have no way to try this

hi thanks allot!
both options worked.

""just because i can." ah but you can't, that is why your here..."

i did try to add DECLARE_SERIAL(SERIAL_PORT_2); into hal.h
but i needed a bit more.

and it's not a shame to ask for help if you dont see it right away.

but many thanks for helping me!