AN1857 Freescale Semiconductor / Motorola, AN1857 Datasheet - Page 43

• Manufacturer Part Number: AN1857
• Description: A 3-Phase ac Induction Motor Control System Based on the MC68HC908MR32
• Manufacturer: Freescale Semiconductor / Motorola

AN1857
MOTOROLA
A software timer routine provides the timing sequence for required
subroutines. A software timer is performed instead of an output compare
interrupt handler. The main program has several time-demanding
interrupt routines, and more interrupt requirements can cause a software
fault.
The software timer routine has two timed outputs:
The interrupt handlers have these functions:
1. READ_CONST is a routine that scans inputs, calculates the speed
2. PI_CONST is a routine that provides overvoltage protection during
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command, handles fault routines, and the LED driver.
deceleration, speed ramp (acceleration/deceleration), PI
controller, and V/Hz ramp, and provides parameters for PWM
generation.
The input capture interrupt handler reads the time between two
subsequent input capture edges (basic part of the process speed
sensor).
The fault interrupt handler takes care of overcurrent fault interrupt
(overcurrent part of the process fault control).
The PWM interrupt handler generates a system of 3-phase
voltages for the motor (process PWM generation).
The input capture interrupt handler on channel 0 timer A performs
the synchronization for the PFC.
Output compare interrupt handler generates the waveform of the
input current.
The A/D interrupt handler performs control of the PFC output
voltage.
The SCI read interrupt handler services receive interrupts for
PC-Master communication routines.
The SCI transmit interrupt handler services transmit interrupts for
PC-Master communication routines.
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Application Note
Software
43