st7fmc2s7t6 STMicroelectronics, st7fmc2s7t6 Datasheet - Page 161

• Manufacturer Part Number: st7fmc2s7t6
• Description: 8-bit Mcu With Nested Interrupts, Flash, 10-bit Adc, Brushless Motor Control, Five Timers, Spi, Linsci
• Manufacturer: STMicroelectronics

MOTOR CONTROLLER (Cont’d)
10.6.6.10 Commutation Noise Filter
For D event detection and for Z event detection
(when SPLG bit is set while DS[3:0] bits are reset),
sampling is done at f
OFF time (“Sampling block” on page 158). To
avoid any erroneous detection due to PWM com-
mutation noise, an hardware filter of 1µs (for f
IPH
is put OFF has been implemented. This means
Table 34. Sensor/sensorless mode and D & Z event selection
Note: For f
SR
bit
0
0
0
0
1
= 4Mhz) when PWM is put ON and when PWM
SPLG
bit
0
1
0
1
x
DS[3:0]
equal to
equal to
SCF
bits
000
000
000
000
Not
Not
xxx
selection, see
not used
not used
not used
not used
Sensors
Sensors
Sensors
Sensors
Sensors
Position
Mode
used
SCF
during the PWM ON or
OS1 dis-
bits use
Enabled
Enabled
Enabled
Enabled
OS[2:0]
abled
Table 82
Z: SA&OT config.
Z: SA&OT config.
Event detection
sampling clock
PWM frequency
PWM frequency
D:
D:
D:
D:
Z:
Z:
Z:
f
f
f
f
f
f
f
SCF
SCF
SCF
SCF
SCF
SCF
SCF
PER-
During off time
behaviour for
the off time of
the PWM sig-
or ON time of
the PWM sig-
At the end of
PWM signal
PWM signal
During OFF
PWM signal
time or ON
During ON
During ON
that, with sampling at 1MHz (1µs), due to this filter,
1 sample are ignored directly after the commuta-
tion.
This filter is active all the time for the D event and
it is active for the Z event when the SPLG bit is set
and DS[3:0] bits are cleared (meaning that the Z
event is sampled at high frequency during the
PWM ON or OFF time).
time of the
time of the
time of the
Sampling
detection
Z event
nal
nal
No Z Window Filter
Only Z Event Filter
Event Filters
Window and
Sensor mode
is active in
ST7MC1/ST7MC2
and “after Z” behaviour
“between D and Z” be-
“between D and Z” be-
“between D and Z” be-
“between D and Z” be-
“Before D” behaviour,
“Before D” behaviour,
“Before D” behaviour,
“Before D” behaviour,
“Before Z” behaviour
haviour and “after Z”
haviour and “after Z”
haviour and “after Z”
haviour and “after Z”
Behaviour of the
output PWM
behaviour
behaviour
behaviour
behaviour
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