Zero-Crossing Detection
Technical Summary
2-17
2.16 Quadrature Encoder/Hall-Effect Interface
The DSP56F803EVM board contains a Quadrature Encoder/Hall-Effect interface
connected to the DSP’s Quad Encoder input port. The circuit is designed to 3.0V
to +5.0V encoder or Hall-Effect sensor inputs. Input noise filtering is supplied on the input
path for the Quadrature Encoder/Hall-Effect interface, along with additional noise
rejection circuitry inside the DSP.
shows the encoder interface.
2.17 Zero-Crossing Detection
An attached UNI-3 motor drive board contains logic that can send out pulses when the
phase voltage of an attached 3-phase motor drops to zero. The motor drive board circuits
generate a 0 to +3.3V DC pulse via voltage comparators. The resulting pulse signals are
sent to a set of jumper blocks shared with the Encoder/Hall-Effect interface. The jumper
blocks allow the selection of Zero-Crossing signals or Quadrature Encoder/Hall-Effect
signals. When in operation, the DSP will only monitor one set of signals, either the
Encoder/Hall-Effect or the Zero-Crossing.
shows the Zero-Crossing and
Encoder/Hall circuits.
Figure 2-13. Zero-Crossing Encoder Interface
ZERO_X_A
ZERO_X_B
ZERO_X_C
1
2
3
4
5
6
+5.0V
FILTER
FILTER
FILTER
FILTER
PIN 1: +5.0V
PIN 2: GROUND
PIN 3: PHASE A
PIN 4: PHASE B
PIN 5: INDEX
PIN 6: HOME
1
2
3
4
5
6
7
8
9
JG7
DSP56F803
PHASEA
PHASEB
INDEX
HOME
J2
Summary of Contents for DSP56F803
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