Hello!
My PP A1 is awesome 
I have just one weird minor problem.
After hitting homing button, the axis x and y homes correctly.
Then it should go to save position for Z homing. But it does not.
Instead of that it just stays on place and left nozzle (N1) starts rotating indefinitely.
After like 10 spins (tube is a lot twisted) it restarts.
Then I try again and everything is fine.
It did not do it in past.
Do anyone have similar experience?
Thanks!
Hi,
This issue was caused by unstable homing trigger signals and ultimately resulting in a timeout that triggered a system reboot.
The issue has now been well resolved.
You can resolve it by downloading the latest Marlin firmware for the A1 (with the “b” suffix) and compiling and updating your system.
https://docs.pandaplacer.com/download
After updating the firmware, you may encounter some drivers running in the opposite direction (due to inconsistent driver versions of the A1).
Search for “Invert the stepper direction” in Configuration.h, and invert the direction as needed in the section below. Then recompile and update the firmware.
OK, it is done, the problem is gone
One step not mentioned anywhere was to install STM32 BOOTLOADER driver.
I did it installing STM32CubeProgrammer. To download it from official ST website I must insert my email.
Then I used their CLI tool to backup old firmware.
After that, the upload from VC code was easy!
Thank you Leo!
I’ve had this problem for some time, just found this thread today.
I reflashed with the new firmware to solve the infinite rotation on init problem.
The first flash worked, but X direction was reversed.
After correcting X and reflashing, Y direction was reversed.
After correcting Y and reflashing, the motion controller COM port disappeared.
The other USB devices still appear normally (cams, CH340, hub), but the STMicro motion port does not. Windows shows “Unknown USB Device (Device Descriptor Request Failed)”. Linux also no longer shows the STMicro device.
Board is PD_MC_V2.2 / STM32F103RET6.
What is the recommended recovery procedure from here?
Hi, when USB recognition fails it is always really uncorftable situation. I would try different cable or/and different PC. I think the bootloader should always work no matter of firmware.
But.. if everything other works it is weird..
When I assemblied my panda with old firmware, the x axis was reversed. I just swapped phases in connector of stepper motor.
Maybe this can help and you don’t have to deal with firmware flashing anymore.
Hi,
Your current issue appears to be a damaged mainbaord /MCU. Typically, updating the firmware or wrong driver direction does not cause these problems.
For V2.X mainbaord, you can replace it with a new STM32F103RCT6. First, burn the bootloader’s bin file via the SWD interface. Afterward, you can complete the upgrade in VScode under the Windows system using the default firmware configuration file. The firmware’s readme.txt contains these instructions.
Alternatively, if recovery proves impossible or you’d prefer something simpler, you can contact me (message here or email) to get a new V3.X mainbaord for replacement. The new version of the mainbaord offers more protection.
Yes, for situations where the motor is rotating in the opposite direction, a simple method that doesn’t require a firmware update is to use tweezers to reverse the order of the 4P connector on the motor wire. For example, change the sequence from black-green-red-blue to blue-red-green-black. This will reverse the stepper motor’s rotation direction.