SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 791

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

Figure 33-16. Input Stage
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
TIOA0
TIOB0
TIOB1
INVA
INVB
By means of the MAXFILT field in TC_BMR, it is possible to configure a minimum duration for
which the pulse is stated as valid. When the filter is active, pulses with a duration lower than
MAXFILT+1 * tMCK ns are not passed to down-stream logic.
Filters can be disabled using the FILTER field in the TC_BMR register.
Input filtering can efficiently remove spurious pulses that might be generated by the presence of
particulate contamination on the optical or magnetic disk of the rotary sensor.
Spurious pulses can also occur in environments with high levels of electro-magnetic interfer-
ence. Or, simply if vibration occurs even when rotation is fully stopped and the shaft of the motor
is in such a position that the beginning of one of the reflective or magnetic bars on the rotary
sensor disk is aligned with the light or magnetic (Hall) receiver cell of the rotary sensor. Any
vibration can make the PHA, PHB signals toggle for a short duration.
INVIDX
1
1
1
SWAP
IDXPHB
1
PHA
PHB
Input Pre-Processing
IDX
MAXFILT
Filter
Filter
Filter
FILTER
1
1
1
Direction
and
Edge
Detection
SAM3S8/SD8
SAM3S8/SD8
PHedge
DIR
IDX
791
791