MC3PHAC Monolithic Intelligent Motor Controller, Rev. 2

22

Freescale Semiconductor

Operation

exception to this rule is that PC master software allows reading locations $0001, $0036 and $FE01, which

are PORTB data register, Dead Time register and SIM Reset Status registers respectively. The

addresses for the WRITEVARx commands are checked for validity, and the data field is also limited to a

valid range for each variable. See Table 6 for a list of valid data values and valid write addresses.

User interface variables and their associated PC master software addresses within the MC3PHAC are

listed in Table 6.

Table 6. User Interface Variables for Use with PC Master Software

Name

Address

Read/

Write

Size

(Bytes)

Description

Valid Data

Commanded direction

$1000

W

1

Determines whether the motor should

go forward, reverse, or stop

Forward — $10

Reverse — $11

Stop — $20

Command reset

$1000

W

1

Forces the MC3PHAC to perform an

immediate reset

$30

Commanded PWM

$1000

W

1

Specifies the frequency of the

MC3PHAC PWM frequency

5.3 kHz — $41

10.6 kHz — $42

15.9 kHz — $44

21.1 kHz — $48

Measured PWM

period

$00A8

R

2

The modulus value supplied to the

PWM generator used by the

MC3PHAC — value is multiplied by

250 ns to obtain PWM period

$00BD–$05E8

Commanded PWM

$1000

W

1

Specifies the polarity of the MC3PHAC

PWM outputs. This is a write once

parameter after reset.

Example: $50 = Bottom and top PWM

outputs are positive polarity.

B + T + $50

B + T – $54

B – T + $58

B – T – $5C

$0036

R/W

1

Specifies the dead time used by the

PWM generator.

Dead time = Value * 125 ns.

This is a write-once parameter.

$00–$FF

$1000

W

1

Specifies the motor frequency at which

full voltage is applied

60 Hz — $60

50 Hz — $61

$0060

R/W

2

$0000–$7FFF

Commanded motor

$0062

R/W

2

Commanded frequency in Hz.

$0000–$7FFF

Actual frequency

$0085

R

2

$0000–$7FFF

$00C8

R

1

Status byte

$00–$FF

Voltage boost

$006C

R/W

1

0 Hz voltage.

%Voltage boost = Value/$FF

$00–$FF

Modulation index

$0091

R

1

Voltage level (motor waveform

amplitude percent assuming no bus

ripple compensation)

Modulation index = value/$FF

$00–$FF