TMC428 DATASHEET (v. 2.02 / April 26 , 2006)
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TMC428 – DATASHEET
Intelligent Triple Stepper Motor Controller with
Serial Peripheral Interfaces
TRINAMIC Motion Control GmbH & Co. KG
Sternstrasse 67
D – 20357 Hamburg
GERMANY
P +49 - (0) 40 - 51 48 06 - 0
F +49 - (0) 40 - 51 48 06 - 60
www.trinamic.com
info@trinamic.com
1 Features
The TMC428 is a miniaturized high performance stepper motor controller. It controls up to three 2-
phase stepper motors. All motors can operate independently. The TMC428 allows up to 6 bit micro
step resolution – corresponding to 64 micro steps per full step – individually selectable for each motor.
Once initialized, it performs all real time critical tasks autonomously based on target positions and
velocities, which can be altered on-the-fly. So, an inexpensive microcontroller together with the
TMC428 forms a complete motion control system. The microcontroller is free to do application specific
interfacing and high level control functions. Both, the communication with the microcontroller and with
one to three daisy chained stepper motor drivers take place via two separate 4 wire serial peripheral
TM*
interfaces. The TMC428 directly connects to SPI smart power stepper motor drivers.
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Controls up to three 2-phase stepper motors
Serial 4-wire interface for µC with easy-to-use protocol
TM
Configurable interface for SPI motor drivers
TM
Different types of SPI stepper motor driver chips may be mixed within a single daisy chain
TM
Communication on demand minimizes traffic to the SPI stepper motor driver chain
TM
Programmable SPI data rates up to 1 Mbit/s
Wide range for clock frequency – can use CPU clock up to 16 MHz
Internal 24 bit wide position counters
Full step frequencies up to 20 kHz
Read-out facility for actual motion parameters (position, velocity, acceleration) and driver status
Individual micro step resolution of {64, 32, 16, 8, 4, 2, 1} micro steps via built-in sequencer
Programmable 6 bit micro step table with up to 64 entries for a quarter sine-wave period
Built-in ramp generators for autonomous positioning and speed control
On-the-fly change of target motion parameters (like position, velocity, acceleration)
Automatic acceleration dependent current control (power boost)
Low power operation: Only 1.25 mA @ 4 MHz (typ.)
Power down mode with transparent wake-up for normal operation
3.3V or 5V operation with CMOS / TTL compatible IOs (all inputs Schmitt-Trigger)
Available in ultra small 16 pin SSOP package and small 24 pin SOP package
*
SPI is Trademark of Motorola, Inc.
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
TMC428 DATASHEET (v. 2.02 / April 26 , 2006)
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Life support policy
TRINAMIC Motion Control GmbH & Co. KG does not
authorize or warrant any of its products for use in life
support systems, without the specific written consent
of TRINAMIC Motion Control GmbH & Co. KG.
Life support systems are equipment intended to
support or sustain life, and whose failure to perform,
when properly used in accordance with instructions
provided, can be reasonably expected to result in
personal injury or death.
© 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
Information given in this data sheet is believed to be
accurate and reliable. However no responsibility is
assumed for the consequences of its use nor for any
infringement of patents or other rights of third parties
which may result form its use.
Specifications subject to change without notice.
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
TMC428 DATASHEET (v. 2.02 / April 26 , 2006)
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2 General Description
The TMC428 is a miniaturized high performance stepper motor controller with a unique price /
performance ratio for both, high volume automotive and for demanding industrial motion control
applications. Once initialized, the TMC428 controls up to three 2-phase stepper motors. Its low price
makes it attractive also for applications, where only one or two stepper motors have to be controlled
simultaneously.
The TMC428 performs all real time critical tasks autonomously. Thus a low cost microcontroller is
sufficient to perform the tasks of initialization, application specific interfacing, and to specify target
positions and velocities. The TMC428 allows on-the-fly change of all motion target parameters also
during motion. Any other parameter may be changed at any time– also during motion –which does not
make sense in any case, but this uniform access to any TMC428 register simplifies application
programming. Read-back option for all internal registers simplifies programming. With its internal
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position counters , the TMC428 can perform up to 2 steps respectively micro steps fully independent
from the microcontroller. The step resolution– individually programmable for each stepper motor –
ranges from full step (1 ‘’micro step’’ is one full step), half step (2 ‘’micro steps’’ per full step), up to 6
bit micro stepping (64 micro steps per full step) for precise positioning and noiseless stepper motor
rotation (Table 8-8, page 26). Optionally, the micro step table– common for all motors –can be adapted
to motor characteristics to further reduce torque ripple.
The TMC428 has got serial interfaces for communication with the microcontroller and for the stepper
motor drivers. The serial interface for the microcontroller uses a fixed length of 32 bits with a simple
TM
protocol, directly connecting to SPI interfaces. The serial interface to the stepper motor drivers is
flexibly configurable for different types– even from different vendors –with up to 64 bit length for the
SPI daisy chain. TRINAMIC smart power stepper motor drivers TMC236, TMC239 and TMC246,
TMC249 perfectly fit to the TMC428. Without additional hardware, drivers with same serial interface
polarities of chip select and clock signals may be mixed in a single chain. To mix drivers with different
serial interface polarities, additional inverters (e.g. 74HC04, 74HC14) are required. For those driver
chips without serial data output, two additional variants of the TMC428 with two additional chip select
outputs are available. The TMC428 sends data to the driver chain on demand only, which minimizes
the interface traffic and reduces the power consumption.
Hint:
Unused reference switch inputs should be pulled to ground (Figure 2-1). With this one can
connect reference switches that connect to +5V resp. +3.3V when pushed. Concerning different
reference switch configurations please refer to Figure 9-3, Figure 9-4, Figure 9-5.
Reference Switch Inputs
(active high)
1K
1K
1K
*For details concerning electrical connections of
the TMC236 / TMC239 / TMC246 / TMC249
refer to its datasheet.
REF1
SS
nSCS_C
REF2
REF3
nSCS_S
CSN
*
SDI
SDO
TMC23x / TMC24x
SCK
SCK_S
MOSI
µC
SCK
MISO
CLK
SDI_C
TMC428-I /
TMC428-A
CLK
V33
V5
TEST
GND
SDO_S
CSN
*
SDI
SDO
TMC23x / TMC24x
SCK
CSN
*
SDI
SDO
TMC23x / TMC24x
SCK
SCK_C
SDO_C
SDI_S
470
nF
Note:
output SDO_C will
nerver be high impedance
+5 V
100 nF
10K
SM#3
SM#2
SM#1
Figure 2-1: TMC428 application environment with TMC428 in SSOP16 package
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
TMC428 DATASHEET (v. 2.02 / April 26 , 2006)
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REF1
REF2
REF3
nSCS3
nSCS2
SS
nSCS_C
nSCS_S
MOSI
µC
SCK
MISO
CLK
SDI_C
TMC428-PI24 /
TMC428-DI20
nSCS
SDO_S
SDI
Driver
w/o SDO
SCK
SDI
nSCS
Driver
w/o SDO
SCK
SDI
nSCS
Driver
w/o SDO
SCK
SDO
SCK_C
SDO_C
CLK V33
V5 V5
TEST GND GND
SCK_S
SDI_S
470 nF
10K
Note:
output SDO_C will
nerver be high impedance
+5 V
SM#3
SM#2
SM#1
Figure 2-2: Usage of drivers without serial data output (SDO) with TMC428 in larger packages
(*the
DI20 package variant is not recommended for new designs)
2.1
Step Frequencies
TM
The maximum SPI data rate is the clock frequency divided by 16. The maximum step frequency
TM
depends on the total length of the datagrams sent to the SPI stepper motor driver chain. At a clock
TM
frequency of 16 MHz, with a daisy chain of three SPI stepper motor drivers of 16 bit datagram length
each, the maximum
full step
frequency is 16 MHz / 16 / ( 3 * 16 ). This is approximately 20 kHz and
that is much higher than needed for typical stepper motors. But, the micro step rate may be higher,
TM
even if the stepper motor driver does not see all micro steps due to SPI data rate limit, as long as the
number of skipped micro steps is less than a full step. In this respect, one should remember, that at
high step rates– respectively pulse rates –the differences between micro stepping and full step
excitation vanishes.
2.2
Modes of Motion
The TMC428 has four different modes of motion, programmable individually for each stepper motor,
named RAMPMODE, SOFTMODE, VELOCITYMODE, and HOLDMODE. For positioning applications
the RAMPMODE is most suitable, whereas for constant velocity applications the VELOCITYMODE is.
In RAMPMODE, the user just sets the position and the TMC428 calculates a trapezoidal velocity profile
and drives autonomously to the target position. During motion, the position may be altered arbitrarily.
The SOFTMODE is similar to the RAMPMODE, but the decrease of the velocity during deceleration is
done with a soft, exponentially shaped velocity profile. In VELOCITYMODE, a target velocity is set by
the user and the TMC428 takes into account user defined limits of velocity and acceleration. In
HOLDMODE, the user sets target velocities, but the TMC428 ignores any limits of velocity and
acceleration, to realize arbitrary velocity profiles, controlled completely by the user. The TMC428 has
capabilities to generate interrupts depending on different stepper motor conditions chosen by an
interrupt mask. However, status bits sent back automatically to the microcontroller each time it sends
data to the TMC428 are sufficient for polling techniques.
The TMC428 provides different modes for reference switch handling. In the default reference switch
mode, the three reference switch inputs (REF1,
REF2, REF3)
are defined as left side reference
st
switches, one for each stepper motor. In another mode, the 1 reference input (REF1) is defined as left
nd
reference switch input of motor number one, the 2 reference input (REF2) is defined as left reference
rd
switch input of motor number two, and the 3 reference input (REF3) is defined as right reference
switch of stepper motor number one. In that mode, there is no reference switch input available for
stepper motor three. With an external multiplexer 74HC157 any stepper motor may have a left and a
right reference switch.
Many serial stepper motor drivers provide different status bits (driver active, inactive, ...) and error bits
(short to ground, wire open, ...). To have access to those error bits, datagrams with a total length up to
48 bits sent back from the stepper motor driver chain to the TMC428 are buffered within two 24 bit
wide registers. The microcontroller has direct access to these registers. Although, the TMC428
provides datagrams with up to 64 bits, only the last 48 bits sent back from the driver chain are buffered
for read out by the microcontroller. This is because buffering of 3 times 16 bits is sufficient for a chain
of three stepper motor drivers (see Figure 2-1, page 3) and most other drivers sending back up to 16
bits. For a chain of three TMC236 / TMC239 / TMC246 / TMC249 all status bits are accessible. From
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
TMC428 DATASHEET (v. 2.02 / April 26 , 2006)
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the software point of view, the TMC428 provides a set of registers, accessed by a microcontroller (µC)
via a serial interface in an uniform way. Each datagram contains address bits, a read-write selection
bit, and data bits, to access the registers and the on-chip memory. Each time, the µC sends a
datagram to the TMC428, it simultaneously receives a datagram from the TMC428. This simplifies the
communication with the TMC428 and makes the programming easy. Most microcontrollers have an
TM
SPI hardware interface, which directly connects to the serial four wire microcontroller interface of the
TM
hardware, a software doing the serial communication is
TMC428. For microcontrollers without SPI
completely sufficient and can easily be implemented.
2.3
Notation of Number Systems & Notation of Two to the Power of n
Decimal numbers are used as usual without additional identification. Binary numbers are identified by a
prefixed % character. Hexadecimal numbers are identified by a prefixed $ character. So, for example
the decimal number 42 in the decimal system is written as %101010 in the binary number system, and
it is written as $2A in the hexadecimal number system. With this, TMC428 datagrams are written as 32
bit numbers (e.g. $1234ABCD = %00010010001101001010101111001101). In addition to the basic
arithmetic operators (+, -, *, /) the operator
two to the power of n
is required at different sections of this
n
data sheet. For better readability instead of 2 the notation 2^n is used.
2.4
Signal Polarities
Per default, signals– external and internal –are high active, but the polarity of some signals is
programmable to be inverted. A pre-fixed lower case ‘n’ indicates low active signals (e.g. nSCS_C,
nSCS_S). For example the polarity of nSCS_S can be inverted by programming, but also the polarity of
datagram bits can be inverted by programming (see section 9, page 27).
2.5
Units of Motion Parameters
Motion parameters position, velocity, and acceleration are given as integer values within TMC428
specific units. Section 8.14 page 26 explains, how to calculate steps, steps per second, steps per
second square from given TMC428 integer values. With a given stepper motor resolution one can
calculate physical units for angle, angular velocity, angular acceleration.
2.6
Representation of Signed Values by Two’s Complement
Those motion parameters that have to cover negative and positive motion direction as well, are
processed as signed numbers represented by two’s complement as usual. Signed motion parameters
are x_target, x_actual, v_target, v_actual, a_actual. Limit motion parameters as v_min, v_max, a_max,
a_threshold, are represented as unsigned binary numbers.
2.7
Tables of Contents
A table of contents, a table of figures, and a table of tables are located at the end of the data sheet.
3 Package Variants
The TMC428 is available in three different package variants, qualified for the industrial temperature
range. An additional variant is available for the automotive temperature range. The package outlines
and dimensions are included within this data sheet (page 45-47.)
part number
TMC428-I
TMC428-A
TMC428-PI24
TMC428-DI20
Package
SSOP16 – 150 mils, 16 pins, plastic package, industrial (-40°C ... +85°C)
SSOP16 – 150 mils, 16 pins, plastic package, automotive (-40°C ... +125°C)
SOP24 – 300 mils, 24 pins, plastic package, industrial (-40°C ... +85°C)
DIL20 – 300 mils, 20 pins, plastic package, industrial (-40°C ... +85°C)
[This
package variant is not recommended for new designs]
JEDEC Drawing
MO-137 (150 mils)
MO-137 (150 mils)
MS-013 (300 mils)
MS-001 (300 mils)
Table 3-1: TMC428 package variants
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG
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