Motorola M68HC08 - Manual (Page 156)

User Guide
Designer Reference Manual DRM028 — Rev 0
156 User Guide MOTOROLA
22. Set minimal speed
23. Set maximal speed and observe the speed transient
24. Set minimal speed and observe the speed transient
25. Then, modify the regulator parameters with PC master software
as in steps 11. to 14.
26. Change SPEED_MIN_RPM if problems occur at low speed
27. Repeat steps 21. to 25. until regulation is improved
28. Open const_cust_x.h and modify the regulator parameters with
the final variable values evaluated with PC master software
29. Build the code (see Software Execution and Build )
Most important software settings are described in previous sections, but
for some applications, PWM frequency must be modified. It is described
in
PWM Frequency and Current Sampling Period Setting .
Once you set the speed control and the motor is running in all start,
speed up, and slow down conditions, the software parameters are set for
the motor. Remember that all parameters are set in const_cust_x.h.
Then, it is possible to program the FLASH memory of the
MC68HC908MR32 device.
6.5.7 PWM Frequency and Current Sampling Period Setting
PWM frequency and current sampling period settings are not usually
needed. The PWM frequency also affects the current sampling period.
Consequently, the current regulation setting should be done, while
understanding their mutual dependency. Therefore, the PWM frequency
setting is provided in the file const.h, instead of const_cust_x.h.
6.5.7.1 PWM Frequency
For the PWM frequency setting, follow the label
CAN_CHANGE_FPWM_n in const.h file.
The PWM frequency setting is provided by:
/* CAN_CHANGE_FPWM_1: */
#define SET_PER_PWM 32.0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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