[BUG] Sensorless homing does not work with 2240s & potential reboots

[thisiskeithb]

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

Yes, and the problem still exists.

Bug Description

Testing was done on a BIQU BX with 2240s installed on X, Y, Z1, Z2, and E0 with sensorless homing.

Edit: I am also now testing this on a Prusa MK3S/+ Bear with BTT002 & 2240s installed on X & Y

---

I can move each axis around, but sensorless homing does not work and drivers shut down. There are also still compile issues when enabling TMC_DEBUG.

Details

I tried a standard G28 and there's an slight attempt to home X & Y, but they instantly trigger (or so I thought) and I can no longer command X or Y to move until a power cycle.

I tried enabling TMC_DEBUG to collect more info, but it won't compile to due various references to TSTEP. I had to disable the following in tmc_util.cpp to get TMC_DEBUG to compile:

Click me for the diff!

diff --git a/Marlin/src/feature/tmc_util.cpp b/Marlin/src/feature/tmc_util.cpp
index fb17e56..e7f0414 100644
--- a/Marlin/src/feature/tmc_util.cpp
+++ b/Marlin/src/feature/tmc_util.cpp
@@ -715,13 +715,13 @@
   #endif
 
   template <typename TMC>
-  void print_tstep(TMC &st) {
-    const uint32_t tstep_value = st.TSTEP();
-    if (tstep_value != 0xFFFFF)
-      SERIAL_ECHO(tstep_value);
-    else
-      SERIAL_ECHOPGM("max");
-  }
+  // void print_tstep(TMC &st) {
+  //   const uint32_t tstep_value = st.TSTEP();
+  //   if (tstep_value != 0xFFFFF)
+  //     SERIAL_ECHO(tstep_value);
+  //   else
+  //     SERIAL_ECHOPGM("max");
+  // }
   void print_tstep(TMC2660Stepper &st) { }
 
   template <typename TMC>
@@ -749,7 +749,7 @@
       case TMC_CS_ACTUAL: print_cs_actual(st); break;
       case TMC_VSENSE: print_vsense(st); break;
       case TMC_MICROSTEPS: SERIAL_ECHO(st.microsteps()); break;
-      case TMC_TSTEP: print_tstep(st); break;
+      //case TMC_TSTEP: print_tstep(st); break;
       #if ENABLED(HYBRID_THRESHOLD)
         case TMC_TPWMTHRS: SERIAL_ECHO(uint32_t(st.TPWMTHRS())); break;
         case TMC_TPWMTHRS_MMS: {
@@ -1006,7 +1006,7 @@
         PRINT_TMC_REGISTER(GSTAT);
         PRINT_TMC_REGISTER(IOIN);
         PRINT_TMC_REGISTER(TPOWERDOWN);
-        PRINT_TMC_REGISTER(TSTEP);
+        //PRINT_TMC_REGISTER(TSTEP);
         PRINT_TMC_REGISTER(TPWMTHRS);
         PRINT_TMC_REGISTER(CHOPCONF);
         PRINT_TMC_REGISTER(PWMCONF);

With TMC_DEBUG enabled, I found that the following differences between M122 reports before & after homing:

Before homing:

        X    Y    Z    Z2    E
Enabled        false    false    true    true    false
[...snip...]
Driver registers:
        X    0x81:00:40:00
        Y    0x81:00:40:00
        Z    0x81:0F:40:00
        Z2    0x81:0F:40:00
        E    0x81:00:40:00

After homing:

        X    Y    Z    Z2    E
Enabled        true    true    true    true    false
[...snip...]
Driver registers:
        X    0x80:0F:50:22
        Y    0x80:0F:50:24
        Z    0x80:1F:40:7C
        Z2    0x80:1F:40:10
        E    0x81:00:40:00

@dbuezas found that according to the datasheet, this is a driver shutdown due to overheating. That is not really the case since drivers are cool to the touch and they are triggering instantly while homing, even at the least sensitive StallGuard value.

---

Based on reports in the #trinamic channel on our Discord, you can use 5130 as a substitute for 2240, but I didn't have 100% success with that either. Drivers no longer shutdown, but they do not trigger while homing, even at the most sensitive StallGuard setting (opposite of above since hit state has to be flipped per the sanity checks).

There's also a report of a printer rebooting with fixes from #27880, but I have not experienced that issue.

Another interesting find is that 2240s are a lot quieter when configured as 5130s vs. 2240s.

Bug Timeline

Since 2240 suppot was added in #25974

Expected behavior

Sensorless homing and drivers work

Actual behavior

Sensorless homing fails and causes drivers to shutdown until a full power cycle

Steps to Reproduce

1. Install 2240 drivers into BX, including three additional jumpers per driver for SPI mode
2. Update config to support 2240s
3. Build & flash current bugfix-2.1.x to BX
4. Attempt to home all via LCD or G28

Version of Marlin Firmware

bugfix-2.1.x (fde0eaf)

Printer model

BIQU BX

Electronics

Stock electronics except for 2240 drivers

LCD/Controller

Stock TFT

Other add-ons

No response

Bed Leveling

ABL Bilinear mesh

Your Slicer

Prusa Slicer

Host Software

OctoPrint

Don't forget to include

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

Additional information & file uploads

Stock BX config: https://github.com/MarlinFirmware/Configurations/tree/bugfix-2.1.x/config/examples/BIQU/BX

Change all *_DRIVER_TYPEs to 2240 and enable TMC_USE_SW_SPI or use the attached modified config: Configurations-config-examples-BIQU-BX.zip

Don't forget to install three additional jumpers under each driver for SPI mode.

[ellensp]

This bug also applies to TMC2130 #27888 (comment)
commit MarlinFirmware/TMCStepper@d7e12dd rewrote sgt() to make it clearer and broke it.

[dbuezas]

I think I read the bits in the wrong order and there were no fault bits actually.

[thisiskeithb]

Reopening since this still isn't fixed.