ST7FMC2N6B6(2004) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

ST7FMC2N6B6
(Rev.:2004)

8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, BRUSHLESS MOTOR CONTROL, FIVE TIMERS, SPI, LINSCI™

STMicroelectronics 

ST7MC1/ST7MC2

MOTOR CONTROLLER (Cont’d)

9.6.6.10 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 fSCF either during the PWM

ON or OFF time (“Sampling block” on page 155).

To avoid any erroneous detection due to PWM

commutation noise, an hardware filter of 1µs (for

fPERIPH = 4Mhz) when PWM is put ON and when

PWM is put OFF has been implemented. This

means that, with sampling at 1MHz (1µs), due to

this filter, 1 sample are ignored directly after the

commutation.

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 either during

the PWM ON or OFF time).

Table 34. Sensor/sensorless mode and D & Z event selection

SR SPLG DS[3:0]

bit bit bits

Mode

OS[2:0]

bits use

Event detection

sampling clock

Sampling

behaviour for

Z event

detection

Window and

Event Filters

Behaviour of the

output PWM

00

000

Sensors

not used

Enabled

D: fSCF

Z: SA&OT config.

At the end of

the off time of

the PWM sig-

PWM frequency

nal

“Before D” behaviour,

“between D and Z” be-

haviour and “after Z”

behaviour

01

000

Sensors

not used

Enabled

D: fSCF

Z: fSCF

Either during

off time or ON

time of the

PWM signal

“Before D” behaviour,

“between D and Z” be-

haviour and “after Z”

behaviour

0

0

Not

equal to

000

Sensors

not used

Enabled

D: fSCF

Z: SA&OT config.

PWM frequency

During ON

time of the

PWM signal

“Before D” behaviour,

“between D and Z” be-

haviour and “after Z”

behaviour

0

1

Not

equal to

000

Sensors

not used

Enabled

D: fSCF

Z: fSCF

During ON

time of the

PWM signal

“Before D” behaviour,

“between D and Z” be-

haviour and “after Z”

behaviour

1x

xxx

Position

Sensors

used

OS1 dis-

abled

Z: fSCF

Either during

OFF time or No filter in Sensor “Before Z” behaviour

ON time of the

mode

and “after Z” behaviour

PWM signal

Note: For fSCF selection, see Table 83

158/294

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