TMC428 ETC-unknow, TMC428 Datasheet - Page 4

• Manufacturer Part Number: TMC428
• Description: Intelligent Triple Stepper Motor Controller With Serial Peripheral Interfaces
• Manufacturer: ETC-unknow

TMC428 DATA SHEET (V. 1.00 / February 12, 2001)
Figure 2 – Usage of Drivers without Serial Data Output (SDO) with TMC428 in SOIC24 Package
The maximum SPI
on the total length of the datagrams send to the SPI
16 MHz, with a daisy chain of three SPI
maximum full step frequency is 16 MHz / 16 / ( 3 * 16 ) which is approximately 20 kHz. But, the micro
step rate may be higher, even if the stepper motor driver loses micro steps due to SPI
long as the number of skipped micro steps is less then 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.
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 trapezoid 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 amount of 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 send back automatically to the micro controller each
time it sends data to the TMC428 are sufficient for polling techniques. Error condition handling of stepper
motor drivers can be handled by read out option of data bits– up to 48 bits, which is sufficient for most
stepper motor drivers – send back from the drivers to the TMC428.
Without any additional logic, in the default reference switch mode, the three reference switch inputs are
defined as left side reference switches, one for each stepper motor. In another mode, the 1
input is defined as left reference switch input of motor number one, the 2
left reference switch input of motor number two, and the 3
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.
Serial stepper motor drivers provide different status bits (driver active, in-active, ...) and error bits (short to
ground, wire open, ...). To have access to those error bits, datagrams with a total length up to 48 bits
Copyright © 2000, TRINAMIC Microchips GmbH
TRINAMIC
M I C R O C H I P S
CLK
µC
MOSI
MISO
SCK
SS
TM
nSCS_C
SDI_C
SCK_C
SDO_C
data rate is the clock frequency divided by 16. The maximum step frequency depends
CLK
V33
TMC428-PI24
REF1
470 nF
V5
REF2
+5 V
V5
TEST
REF3
GND
GND
TM
stepper motor drivers of 16 bit datagram length each, the
nSCS_S
SDO_S
nSCS2
SCK_S
nSCS3
SDI_S
TM
10K
CLK
SDI
stepper motor driver chain. At a clock frequency of
w/o SDO
Driver
nSCS
SCK
rd
SM#3
reference input is defined as right reference
CLK
SDI
w/o SDO
nd
Driver
nSCS
SCK
reference input is defined as
SM#2
TM
data rate limit, as
CLK
SDI
Driver
nSCS
SCK
st
reference
SM#1
SDO
4
4