TMC453 DATASHEET V2.3
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Copyright 1997-1999, TRINAMIC Microchips GmbH
Table of contents
1
Features ..........................................................................................................................................................4
2
Introduction ....................................................................................................................................................4
2.1
Control of Stepper Motors .......................................................................................................................4
2.2
Microstepping..........................................................................................................................................4
2.3
More precision using motor current control..............................................................................................5
2.4
Conclusion ...............................................................................................................................................5
3
Block diagram .................................................................................................................................................6
4
Electrical data of the TMC453 .........................................................................................................................7
4.1
Pinout ......................................................................................................................................................7
4.2
Absolute Maximum Ratings......................................................................................................................8
4.3
Analog functions......................................................................................................................................8
4.4
Digital part...............................................................................................................................................8
4.5
Characteristics of the analog components of the TMC453 .......................................................................9
5
The Bus interface...........................................................................................................................................11
5.1
Parallel Interface.....................................................................................................................................11
5.2
Serial Interface .......................................................................................................................................12
6
Description of the COMMAND FIFO ..............................................................................................................14
6.1
Accessing the TMC453 ..........................................................................................................................14
6.2
General functionality..............................................................................................................................14
6.3
Description of the registers of the COMMAND FIFO ...............................................................................14
6.3.1
FIFO Commands .............................................................................................................................14
6.3.2
Description of the status bits...........................................................................................................17
6.3.3
STOP and SLOWDOWN-functions ...................................................................................................17
6.3.4
Finding the Reference Position ........................................................................................................17
6.3.5
Programming example for the FIFO.................................................................................................18
7
The Ramp Generator .....................................................................................................................................19
7.1
General Description................................................................................................................................19
7.2
Principle of Operation ............................................................................................................................19
7.3
Programming the Ramp generator .........................................................................................................21
7.3.1
Automatic Ramp generation ...........................................................................................................21
7.3.2
Programmed / Interactive Ramp generation ....................................................................................22
7.3.3
Synchronization of multiple TMC453s.............................................................................................23
7.4
Ramp adaptive motor current control.....................................................................................................24
8
The Incremental Encoder Interface ................................................................................................................25
8.1
General Description................................................................................................................................25
8.2
Registers of the Incremental Encoder Interface.......................................................................................25
9
The Sequencer ..............................................................................................................................................27
9.1
Registers for Sinestep operation .............................................................................................................27
9.1.1
Programming the Sine Generator....................................................................................................28
9.2
Full- and Halfstep Operation...................................................................................................................31
9.2.1
Automatic Phase Pattern Setup.......................................................................................................31
9.2.2
Manual Phase Pattern Setup ...........................................................................................................32
9.3
Registers for Microstep Operation ..........................................................................................................35
9.4
Administration of the different modes of operation and output control .................................................38
10
The PID Controller .....................................................................................................................................41
10.1 General introduction ..............................................................................................................................41
10.1.1
Increasing stepping accuracy and stabilizing the position ................................................................41
10.2 Description of the registers of the PID controller.....................................................................................42
11
Interrupt control and Interrupt Sources ......................................................................................................46
12
TMC453 Register Overview........................................................................................................................48
TMC453 DATASHEET V2.3
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Copyright 1997-1999, TRINAMIC Microchips GmbH
1
Features
General Features
Seven stage command FIFO relieves host
processor from all real-time requirements
Step pulse generation from millihertz to
megahertz
Three 8 Bit DACs for direct microstep control of
2- and 3-phase stepper motors
Optional pulse- and direction interface
8 Bit parallel interface / serial 2-wire interface
Low Power 5V, 0.8m CMOS process
Direct interfacing to industry standard power
drivers
Package: PLCC68 (-PI) / CLCC68 (-CI) or dice
(bare chip) (-D)
Extended temperature range 25..+85C
Ramp Generation
Automatic generation of S-shaped ramps
Synthesis of ramps of any shape with constant,
linear and parabolic segments
Synchronization between multiple TMC453s
Programmable interrupt events
Control inputs for stop and slowdown
Sequencer
Freely programmable halfstep, fullstep and
microstep patterns
Supports 2-, 3- ,4- and 5-phase stepper motors
with unipolar or bipolar control
Sine generator for up to 256 microsteps per
fullstep
Intelligent motor current control
128X8 RAM for user defined microsteps adapted
to the motor characteristics
Direct output of the velocity value for servo
motor control
Incremental Encoder
Supports 2-phase incremental encoders for
position control and feedback control loop
Feedback controlled motion
Stabilization against varying motor loads
Exact position control via incremental encoder
2
Introduction
2.1
Control of Stepper Motors
Stepper motors are historically used in applications, where a positioning to preprogrammed or calculated positions
is needed. Examples are linear and rotational axes in robots. The reason for using stepper motors in these
applications is that they work extremely precise without the necessity to use a control loop. Precautions have to be
taken to avoid overloading the motor, e.g. by too fast movements or too high accelerations. In many of these
applications an incremental encoder is coupled mechanically to the motor to measure the position or velocity or to
detect failures.
New applications for stepper motors have the demand for a high reliability while reducing costs, e.g. the
minimization of mechanical parts, which is possible because the stepper motor provides high torque without gear
and precise positioning without feedback. It is expected that stepper motors and electronically commutated
motors will replace DC motors in many applications which incorporate DC motors today. The reduction in cost is
possible because control electronics continues to get less expensive while costs of mechanic parts cannot be
reduced in such a dramatic way.
The TMC453 is a universal controller for stepper motors. It interfaces directly to a CPU and offloads the CPU from
all time critical tasks.
After setting up the chip with a number of control parameters, the motor can be controlled by simply
programming the target position for a movement. The TMC453 automatically drives the motor with smooth
movement curves (ramps) to reduce mechanical stress and to avoid the loss of steps. Where necessary the CPU can
control all phases of the movement itself.
2.2
Microstepping
A stepper motor has an inherent resolution given by the number of fullsteps per rotation. These positions are
achieved by switching the coils on and off. In applications where a higher step resolution than the inherent step
TMC453 DATASHEET V2.3
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Copyright 1997-1999, TRINAMIC Microchips GmbH
resolution or its double, the halfstep resolution, is required, a control scheme called microstepping can be used. It
allows a positioning of the motor between the full (or half) steps. Therefore the coils of the motor are driven by
weighed currents. In principle, a sine-wave driving scheme would be sufficient, but since the characteristics of
most motors are not linear, it is desirable to be able to program the current patterns for a number of microsteps
between each two fullsteps. Using microstepping can also be necessary to reduce the abruptness of the change
between two full-/halfstep positions.
A stepper motor is very sensitive to static and changing loads in microstep positions. In cases where microstepping
is used to improve the accuracy of positioning, a feedback control system using a position encoder reduces the
need for adjustment of the microstepping table and minimizes the effect of varying loads. The TMC453 contains a
programmable filter to build a PID-(Proportional-Integral-Differential) regulator for position stabilization.
2.3
More precision using motor current control
In most of today's applications based on stepper motors, the motors are driven with the full current, independent
of the torque actually needed. This not only wastes energy, reduces lifetime of electronical and mechanical parts,
but also reduces precision because of the thermal expansion of the mechanical parts.
Since the torque of a stepper motor is a function of the coil current, the required current depends on load and
acceleration. The TMC453 supports an effective means to reduce power consumption: It monitors acceleration
and speed to adjust the motor current according to a user defined table. TMC453 users have reported a dramatic
reduction of thermal problems.
2.4
Conclusion
The TMC453 is an efficient and inexpensive motor controller. It integrates the complete control function set to
drive all kinds of stepper motors and directly interfaces to power drivers. Further on it integrates interfaces and the
logic to control DC servo motors. Programming of the TMC453 is easy, because it integrates all time critical
features in hardware. Only a few parameters have to be programmed to adapt the TMC453 to a given application.
Then the TMC453 does all the positioning by just programming the desired target position and motor velocity. The
TMC453 provides the ultimate function set to get the highest possible resolution without the necessity for
feedback while also integrating the complete logic for feedback control without processor overhead.
stepper
motor
driver
2,3,5-Phase
stepper motor
incremental
encoder
Controller/
PC
parallel Bus
TMC453
TMC453
synchronisation
Ser. Bus
Figure 2-1: System environment of the TMC453
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