ARM IM-AD1 - Manual (Page 64)

Reference Design Example
4-18 Copyright © 2001-2003. All rights reserved. ARM DUI 0163B
4.7.1 Stepper x control register
The stepper controller control register defines the operating mode of the stepper.
Note
You must consider the maximum speed of the stepper motor when programming the
step speed register or issuing consecutive single step commands in the stepper control
register.
Ensure there is a delay, typically a few milliseconds, between a DOCOUNT and a
SINGLESTEP. Failing to leave a delay between the end of the count and writing a
SINGLESTEP command results in unpredictable behavior. The minimum duration of
the delay depends on the stepper motor.
The bits in this register are described in Table 4-11.
Table 4-11 Stepper control register
Bits Name Access Function
7 BUSY Read This bit contains 1 when a count is in progress
and 0 when the count is complete.
6 BUFFERFULL Read This bit contains 1 when the buffer is full and 0
when the buffer is available for a new value to be
written.
An inverted version of this bit is used as an
interrupt source.
5 DRIVE
ENABLE Read/write This bit enables and disables the phase outputs
to the motor. When this bit is 0, ENA, ENB,
PH1, PH2, PH3, and PH4 are held at 0. When
this bit is 1, these signals output the relevant
drive waveform.
4 HALFSTEP Read/write These bits are used in combination to select the
drive mode:
00 = Full step, two phase on (non-wave drive)
drive sequence (see Figure 4-3 on page 4-19)
01 = Full step, one phase on (wave drive) drive
sequence (see Figure 4-4 on page 4-19)
10 = Half step drive sequence (see Figure 4-5 on
page 4-20)
11 = Reserved
3 WAVEDRIVE Read/write