AN1661 Freescale Semiconductor / Motorola, AN1661 Datasheet - Page 7

• Manufacturer Part Number: AN1661
• Description: Low Cost Universal Motor Chopper Drive System
• Manufacturer: Freescale Semiconductor / Motorola

Control Algorithm
AN1661
MOTOROLA
The DIP switch, SW1, allows some options of the drive’s functionality
and is discussed later in this application note.
Pullup resistors R7A–R7E are on-board to provide the proper level of
input signals for the MCU.
The basic principle of the chopper control technique is simple: The
speed can be controlled by adjustment of the voltage applied to the
motor performed by the change of the PWM duty cycle (see
The universal motor is supplied in dc mode through the power stage.
Figure 5
and some subroutines like: MAKE_PI, RAMPE, watchdog and interrupt
services routines. The control block is, in fact, a relatively short loop
which makes a decision on which subroutines will be called.
There is also a universal timing routine, which works with the hardware
(HW) timer and a unique register for every timed subroutine. The timing
routine calculates the difference between the hardware timer and a
particular register and, in case of coincidence with the given number
(time interval), calls the appropriate subroutines.
The same principle is used for all time conditions.
Freescale Semiconductor, Inc.
For More Information On This Product,
shows a state diagram. The software consists of a control block
Go to: www.freescale.com
Control Algorithm
Application Note
Figure
2).
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