After reading several postings about the TC2209 stepper driver’s stallguard capability I learned that there are actually 3 parameters that determine how it works. They are sensitivity, power, and the setting stepper voltage by the tiny trim pot on the top of each driver.
Apparently the only way to get these settings to produce an acceptable result is trial and error. The setting for each stepper – X, Y, and Z – has to be done individually because they are all independent of each other. The settings for sensitivity and for power are in Configuration_adv.h. Fortunately these settings can also be set directly from the printer’s LCD touch screen.
Setting the trim pot is tricky business because only tiny changes can result in a fairly large change in voltage. Plus, once they are installed on the motherboard the space around them is limited and it is easy to cause a short circuit if you use a metal screwdriver.
It is also common for different stepper driver chips to have different characteristics. For example, their trim pots may be set differently, or the silicon in the cship may have different degrees of electrical resistance, or there may be some other difference that is unique to each chip. The bottom line is that even though you buy the chips in groups you have to deal with each chip’s setting individually. Trying to use the same settings for all chips will simply not work.

Since I am configuring my printer to work with sensorless homing and probing for the first time I’ll have to try different settings for sensitivity and power before I arrive at settings that work. I know that the default settings in Marlin do not work (at least for the steppers that I have installed) so i’ll avoid posting values until after I find a set that does work.

Last Update: 26 Jan 2021