ATSAM3S-EK Atmel, ATSAM3S-EK Datasheet - Page 764

• Manufacturer Part Number: ATSAM3S-EK
• Description: KIT EVAL FOR ATSAM3S4C
• Manufacturer: Atmel
• Series: SAM3Sr
• Type: MCUr

Specifications of ATSAM3S-EK

• Contents: Board, Cables, Power Supply
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex-M3
• Kit Contents: Board
• Features: TFT Colour LCD Display, SD/MMC Interface
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

34.6.14.3
Figure 34-18. Rotation Change Detection
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Direction Change under normal conditions
PHA
PHB
DIR
DIRCHG
No direction change due to particulate contamination masking a reflective bar
PHA
PHB
DIR
DIRCHG
SAM3S Preliminary
Direction Status and Change Detection
After filtering, the quadrature signals are analyzed to extract the rotation direction and edges of
the 2 quadrature signals detected in order to be counted by timer/counter logic downstream.
The direction status can be directly read at anytime on TC_QISR register. The polarity of the
direction flag status depends on the configuration written in TC_BMR register. INVA, INVB,
INVIDX, SWAP modify the polarity of DIR flag.
Any change in rotation direction is reported on TC_QISR register and can generate an interrupt.
The direction change condition is reported as soon as 2 consecutive edges on a phase signal
have sampled the same value on the other phase signal and there is an edge on the other sig-
nal. The 2 consecutive edges of 1 phase signal sampling the same value on other phase signal
is not sufficient to declare a direction change, for the reason that particulate contamination may
mask one or more reflective bar on the optical or magnetic disk of the sensor. (Refer to
34-18 ”Rotation Change Detection”
The direction change detection is disabled when QDTRANS is set to 1 in TC_BMR. In this case
the DIR flag report must not be used.
missing pulse
spurious change condition (if detected in a simple way)
same phase
change condition
for waveforms.)
Report Time
6500C–ATARM–8-Feb-11
Figure