tmc2130: Initial support for sensorless homing

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -461,10 +461,18 @@
 #driver_TOFF: 4
 #driver_HEND: 7
 #driver_HSTRT: 0
+#driver_SGT: 0
 #   Set the given register during the configuration of the TMC2130
 #   chip. This may be used to set custom motor parameters. The
 #   defaults for each parameter are next to the parameter name in the
 #   above list.
+#diag1_pin:
+#   The micro-controller pin attached to the DIAG1 line of the TMC2130
+#   chip. Setting this creates a "tmc2130_stepper_x:virtual_endstop"
+#   virtual pin which may be used as the stepper's endstop_pin. Doing
+#   this enables "sensorless homing". (Be sure to also set driver_SGT
+#   to an appropriate sensitivity value.) The default is to not enable
+#   sensorless homing.
 
 
 # Homing override. One may use this mechanism to run a series of

config/generic-einsy-rambo.cfg

@@ -9,6 +9,7 @@ dir_pin: PL0
 enable_pin: !PA7
 step_distance: .005
 endstop_pin: ^PB6
+#endstop_pin: tmc2130_stepper_x:virtual_endstop
 position_endstop: 0
 position_max: 250
 
@@ -17,6 +18,7 @@ cs_pin: PG0
 microsteps: 16
 run_current: .5
 sense_resistor: 0.220
+diag1_pin: !PK2
 
 [stepper_y]
 step_pin: PC1
@@ -24,6 +26,7 @@ dir_pin: !PL1
 enable_pin: !PA6
 step_distance: .005
 endstop_pin: ^PB5
+#endstop_pin: tmc2130_stepper_y:virtual_endstop
 position_endstop: 0
 position_max: 210
 
@@ -32,6 +35,7 @@ cs_pin: PG2
 microsteps: 16
 run_current: .5
 sense_resistor: 0.220
+diag1_pin: !PK7
 
 [stepper_z]
 step_pin: PC2
@@ -39,6 +43,7 @@ dir_pin: PL2
 enable_pin: !PA5
 step_distance: .0025
 endstop_pin: ^PB4
+#endstop_pin: tmc2130_stepper_z:virtual_endstop
 position_endstop: 0.5
 position_max: 200
 
@@ -47,6 +52,7 @@ cs_pin: PK5
 microsteps: 16
 run_current: .5
 sense_resistor: 0.220
+diag1_pin: !PK6
 
 [extruder]
 step_pin: PC3
@@ -70,6 +76,7 @@ cs_pin: PK4
 microsteps: 16
 run_current: .5
 sense_resistor: 0.220
+diag1_pin: !PK3
 
 [heater_bed]
 heater_pin: PG5