AN1914 Freescale Semiconductor / Motorola, AN1914 Datasheet - Page 33

• Manufacturer Part Number: AN1914
• Description: 3-Phase BLDC Motor Control with Sensorless Back EMF Zero Crossing Detection Using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

7.
7.1 Main SW Flow Chart
This section describes the design of the software blocks of the drive. The software will be described in
terms of:
For more information of the used control technique see
The main software flow chart incorporates the Main routine entered from Reset, and interrupt states.
The Main routine includes the initialization of the DSP and the main loop. It is shown in
and
The main loop incorporates Application State Machine - the highest SW level which precedes settings
for other software levels, BLDC motor Commutation Control, Speed Control, Alignment Current
Control, etc. The inputs of Application State Machine are Run/Stop Switch state, Required Speed
Omega and Drive Fault Status. Required Mechanical Speed can be set from PC Master or manually
with Up/Down buttons.
Commutation Control proceeds BLDC motor commutation with the states described in
Section
The Speed Control is detailed description is in sections
Current Control is described in
Run/Stop switch is checked to provide an input for Application State Machine (ApplicationMode Start
or Stop).
The interrupt subroutines provide commutation Timer services, ADC starting in the PWM reload
interrupt, ADC service, ADC Zero Crossing checking, Limit analog values handling, overcurrent and
overvoltage PWM fault handler.
The Commutation Timer ISR is used for Commutation Timing and Commutation Control and Zero
Crossing Checking proceeding.
The Speed/Alignment Timer ISR is used for Speed regulator time base and for Alignment stage
duration timing.
The PWM Reload ISR is used to evaluate BEMF Zero Crossing, start ADC conversion and memorize
Zero Crossing sampling time T_ZCSample.
The ADC Complete ISR is used to read voltages, current and temperature samples from the ADC. It
also sets Current control and when the Current Control setting is enabled.
The other interrupts in
Mechanical Speed input for Application State Machine (ApplicationMode Start or Stop).
•
•
•
Figure
SW Design
Main Software Flow Chart
Data Flow
State Diagram
7.3.4.
7-2.
DSP56F80x MC PWM Module in Motor Control Applications
Freescale Semiconductor, Inc.
Figure 7-2
For More Information On This Product,
Section 7.2.4
Go to: www.freescale.com
are used for System Fault handling and setting of Required
and
Section
Section
Section 7.2.3
7.3.6.
5.
and
Section
7.3.5. Alignment
Section 5
SW Design
Figure 7-1
and
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