Product specifications

R01AN0168ED0101 Rev. 01.01 29
Application Note
Chapter 6 Performing Movements
Within this section, the movement of stepper motors using the Channel
Management
and the Movement Calculator is discussed. Operation with Zero
Point Detection
can be found in Chapter 7 “Performing Zero Point Detection”
on page 37
.
6.1 Parameters and Variables
In order to understand the automated movement of a stepper motor by ISM,
the knowledge about its parameters and variables is essential.
The
Movement Calculator is using the parameters as constants for its
algorithm, and it stores temporary values and results in variables.
Notes 1. The most important variable is VAPn, which shows the actual position in
macro- and microsteps of a (physical) channel
n. If VAPn matches PMPn
(which is the target motor position to move to), the motor movement is
stopped and the interrupt
IRQ_REACHED is generated.
2. Be careful when thinking about the term “channel”. For the PWM tables,
there are
“virtual” channels CCTn. This means, that for each physical
channel
n, a set of PWM values can be chosen. However, all other parts of
ISM, including the
Movement Calculator and its parameters and variables,
are always referring to
physical channels.
For parameters and variables there is no software reset (only by hardware), so
that parameters and variables shall be initialized by software before starting or
re-starting the
Channel Management. Parameters and variables must not be
changed during operation of the
Channel Management, except PMPn.
As an overview, the following parameters and variables are existing for each
physical channel
n, and they are all accessible by software via registers. Most
of them have a common format using 25 bits.
Table 6-1 Parameters of the Movement Calculator
Parameter
Abbreviation /
Bit Name
Width / Bits Register Name
Target Motor Position
a
a)
This parameter is double-buffered. Change by software is possible at any time
without disturbances. On each
START event, the buffered value is updated.
PMP 25 ISMxPAR0CFGn
Damping Factor PDF 3 ISMxPAR1CFGn
Acceleration Limit PAL 25 ISMxPAR2CFGn
Deceleration Limit PDL 25 ISMxPAR3CFGn
Maximum Speed PMS 25 ISMxPAR4CFGn
Hysteresis Correction PHC 25 ISMxPAR5CFGn
Speed Threshold 1 PS1 25 ISMxPAR6CFGn
Speed Threshold 2 PS2 25 ISMxPAR7CFGn
Speed Threshold 3 PS3 25 ISMxPAR8CFGn
Speed Threshold 4 PS4 25 ISMxPAR9CFGn