Z2 stepper motor is only in sync with Z stepper motor when using 16 microsteps

[Nico9n]

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

Yes, and the problem still exists.

Bug Description

I am using 2 stepper motors and drivers (TMC2226 in UART mode) for the Z axis. When I use #define Z_MICROSTEPS 16, everything works as expected. However, when I use #define Z_MICROSTEPS 32 or any other value higher than 16, Z2 spins too fast. Z2 is not in sync with Z.

Bug Timeline

No response

Expected behavior

Z2 should spin at the same speed as Z.

Actual behavior

Z2 spins faster than Z.

Steps to Reproduce

1. Use a printer with separate drivers and motors for Z and Z2.
2. Use TMC drivers in UART mode.
3. Set #define Z_MICROSTEPS 32 or any value higher than 16 in Configuration_adv.h.
4. Adjust the values for DEFAULT_AXIS_STEPS_PER_UNIT depending on the microsteps in Configuration.h
5. Home the Z axis. You will see that Z2 spins too fast.

Version of Marlin Firmware

2.1.x

Printer model

Prusa i3 clone with changes

Electronics

Manta m8p v2 Mainboard

LCD/Controller

Mini 12864 v2.0

Other add-ons

No response

Bed Leveling

None

Your Slicer

Simplify3D

Host Software

None

Don't forget to include

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

Additional information & file uploads

config.zip

m122output.txt

[robherc]

Maybe you nred to set the microsteps on Z2 to match the new microsteps on Z?

[Nico9n]

I tried your suggestion, but the result is the same.

in Configuration_adv.h.
#define Z_MICROSTEPS 32
#define Z2_MICROSTEPS 32

I think the debug output from M122 indicates that the steps are set correctly:
X Y Z Z2
msteps 32 32 32 32

[ellensp]

This is literally not possible. The code is such that for every step on Z a step is also taken on Z2.

So issue is microtepping somewhere.

[ellensp]

I do see a bug, sadly I don't have this hardware to try it on.

The issue I see is that Marlin/src/pins/stm32h7/pins_BTT_MANTA_M8P_V2_0.h has #define Z2_SERIAL_TX_PIN PB5
So it expects Z2 uart to always be on M4 even if your not using M4 for Z2
This would be fine if all z2 pins was set to M4 permanently but it is not.

Ie it has

  #define X_SERIAL_TX_PIN                   PC13      // M1
  #define Y_SERIAL_TX_PIN                   PE3       // M2
  #define Z_SERIAL_TX_PIN                   PB9       // M3
  #define Z2_SERIAL_TX_PIN                  PB5       // M4
  #define E0_SERIAL_TX_PIN                  PG14      // M5
  #define E1_SERIAL_TX_PIN                  PG10      // M6
  #define E2_SERIAL_TX_PIN                  PD5       // M7
  #define E3_SERIAL_TX_PIN                  PC6       // M8

But this breaks the uart pins is your not using the stepper drivers like that

It should be

  #define X_SERIAL_TX_PIN                   PC13      // M1
  #define Y_SERIAL_TX_PIN                   PE3       // M2
  #define Z_SERIAL_TX_PIN                   PB9       // M3
  #define E0_SERIAL_TX_PIN                  PB5       // M4
  #define E1_SERIAL_TX_PIN                  PG14      // M5
  #define E2_SERIAL_TX_PIN                  PG10      // M6
  #define E3_SERIAL_TX_PIN                  PD5       // M7
  #define E4_SERIAL_TX_PIN                  PC6       // M8

And then Z2 is auto set to correct E0 serial pin

Update your Marlin/src/pins/stm32h7/pins_BTT_MANTA_M8P_V2_0.h with these changes and see if it fixes your issue

[thisiskeithb]

This is another one of the boards that follows the original implementation set by the Fysetc Spider board of defining a Z2 instead of everything past Z/Z1 being an extruder driver.

[ellensp]

No it doesn't. there are no other Z2 pins being defined in pins_BTT_MANTA_M8P_V2_0

[thisiskeithb]

No it doesn't. there are no other Z2 pins being defined in pins_BTT_MANTA_M8P_V2_0

There's a Z2 pin literally defined in the pins file 😄 Direct link to pins file / current commit is below:

Marlin/Marlin/src/pins/stm32h7/pins_BTT_MANTA_M8P_V2_0.h

Line 320 in b954959

#define Z2_SERIAL_TX_PIN PB5

[ellensp]

Yes that is the issue.
That only works if the Z2_STEP_PIN, Z2_DIR_PIN and Z2_ENABLE_PIN are also hardcoded into pins_BTT_MANTA_M8P_V2_0
They are not present.
So this board does not have a statically defined Z2, and should not have a statically define Z2 serial pin.

[ellensp]

Config also has

//#define E0_DRIVER_TYPE TMC2209
#define E1_DRIVER_TYPE TMC2209

Which is not valid, you can't have a E1 without a E0

[Nico9n]

I do see a bug, sadly I don't have this hardware to try it on.

The issue I see is that Marlin/src/pins/stm32h7/pins_BTT_MANTA_M8P_V2_0.h has #define Z2_SERIAL_TX_PIN PB5 So it expects Z2 uart to always be on M4 even if your not using M4 for Z2 This would be fine if all z2 pins was set to M4 permanently but it is not.

Ie it has

  #define X_SERIAL_TX_PIN                   PC13      // M1
  #define Y_SERIAL_TX_PIN                   PE3       // M2
  #define Z_SERIAL_TX_PIN                   PB9       // M3
  #define Z2_SERIAL_TX_PIN                  PB5       // M4
  #define E0_SERIAL_TX_PIN                  PG14      // M5
  #define E1_SERIAL_TX_PIN                  PG10      // M6
  #define E2_SERIAL_TX_PIN                  PD5       // M7
  #define E3_SERIAL_TX_PIN                  PC6       // M8

But this breaks the uart pins is your not using the stepper drivers like that

It should be

  #define X_SERIAL_TX_PIN                   PC13      // M1
  #define Y_SERIAL_TX_PIN                   PE3       // M2
  #define Z_SERIAL_TX_PIN                   PB9       // M3
  #define E0_SERIAL_TX_PIN                  PB5       // M4
  #define E1_SERIAL_TX_PIN                  PG14      // M5
  #define E2_SERIAL_TX_PIN                  PG10      // M6
  #define E3_SERIAL_TX_PIN                  PD5       // M7
  #define E4_SERIAL_TX_PIN                  PC6       // M8

And then Z2 is auto set to correct E0 serial pin

Update your Marlin/src/pins/stm32h7/pins_BTT_MANTA_M8P_V2_0.h with these changes and see if it fixes your issue

I have updated the pins_BTT_MANTA_M8P_V2_0.h file, and it fixes my issue. Thank you! :)