Software Design
Designer Reference Manual
DRM028 — Rev 0
92
Software Design
MOTOROLA
Current measurement and current calibration when PWM is OFF
Before testing of the start switch, dc-bus current is measured when
PWM is OFF. This way the dc-bus current measurement path is
calibrated. The calibrated value
Offset0_Curr
is used for the final
current calculation.
This offset on the ADC input should ideally be 1.65 V at 0 dc-bus current.
If the sensed value exceeds the limit (Offset_Max_Curr) when PWM
is OFF, this indicates some hardware error, and the control flow
enters into the fault state:
Start condition test
The start condition is tested. If in manual mode (PCMode = 0), the
start condition is a movement in the switch from stop to start. In PC
master software mode (PCMode = 1), the start condition in switch
start position and StartCtrl = 1. If start condition valid then Strt_F is
set, Stop_F is cleared, and the next state entered.
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..
