
TMC222 DATASHEET (V. 1.12 / March 7, 2011)
19
Copyright 2004-2009 TRINAMIC Motion Control GmbH & Co. KG
7
<Stop> flag allows to distinguish whether state Stopped was entered after HardStop/SoftStop or not. <Stop> is set to
‘1’ when leaving state HardStop or SoftStop and is reset during first clock edge occurring in state Stopped.
8
While in state Stopped, if ActPos ≠ TagPos there is a transition to state GotoPos. This transition has the lowest
priority, meaning that <Stop>, <TSD>, etc. are first evaluated for possible transitions.
9
If <StepLoss> is active, then SetPosition and GotoSecurePosition commands are ignored (they will not modify TagPos
register whatever the state) and motion to secure position is forbidden. Other commands like RunInit or ResetPosition
will be executed if allowed by current state. <StepLoss> can only be cleared by a GetFullStatus1 command.
5.2
RAM and OTP Memory
Some RAM registers (e.g. Ihold, Irun) are initialized with the content of the OTP (One Time
Programmable) memory. The content of RAM registers that are initialized via OTP can be changed
afterwards. This allows user initialization default values, whereas the default values are one time
programmable by the user. Some OTP bits are address bits of the TMC222.
5.2.1
RAM Registers
Register
Mnemonic
Length
(bit)
Related commands
Comment
Reset
State
Actual Position
ActPos
16
GetFullStatus2
ResetPosition
Actual Position of the Stepper Motor. 16-bit
signed
0x0000
Target Position
TagPos
16
SetPosition
GetFullStatus2
ResetPosition
Target Position of the Stepper Motor. 16-bit
signed
Acceleration
Shape
AccShape
1
GetFullStatus1
SetMotorParam
ResetToDefault
0 = Acceleration with Acc Parameter.
1 = Velocity set to Vmin, without
acceleration
Coil Peak Current
Irun
4
GetFullStatus1
SetMotorParam
ResetToDefault
Coil current when motion is ongoing
(Table 12: Irun / Ihold Settings)
OTP
Memory
Coil Hold Current
Ihold
4
GetFullStatus1
SetMotorParam
ResetToDefault
Coil current when motor stands still
(Table 12: Irun / Ihold Settings)
Minimum Velocity
Vmin
4
GetFullStatus1
SetMotorParam
ResetToDefault
Start Velocity of the stepper motor
(Table 4: Vmin )
Maximum Velocity
Vmax
4
GetFullStatus1
SetMotorParam
ResetToDefault
Target Velocity of the stepper motor
(Table 3: Vmax Parameter)
Shaft
1
GetFullStatus1
SetMotorParam
ResetToDefault
Direction of motion
Acceleration /
Deceleration
Acc
4
GetFullStatus1
SetMotorParam
ResetToDefault
Parameter for acceleration
(Table 5: Acc Parameter)
Secure Position
SecPos
11
GetFullStatus2
ResetToDefault
Target Position for GotoSecurePosition
command (6.8.4 GotoSecurePosition); 11
MSBs of 16-bit position (LSBs fixed to ‘0’)
Stepping Mode
StepMode
2
GetFullStatus1
GetFullStatus2
ResetToDefault
Micro stepping mode
(5.1.1 Stepping Modes)