XC164-16 Datasheet, PDF (194/417 Pages) Infineon Technologies AG – 16-Bit Single-Chip Microcontroller with C166SV2 Core Volume 2 (of 2): Peripheral Units

XC164-16 Derivatives
Peripheral Units (Vol. 2 of 2)
Capture/Compare Unit 6 (CAPCOM6)
18.5
Hall Sensor Mode
For Brushless DC-Motors, usually the Multi-Channel Mode is used, as the modulation
patterns need to be output to properly control the motor. These patterns need to be
output in relation to the angular position of the motor. For this, usually Hall sensors or
Back-EMF sensing are used to determine the angular rotor position. The CAPCOM6
provides three inputs, CC6POS0 … CC6POS2, which can be used as inputs for the Hall
sensors or the Back-EMF detection signals.
There is a strong correlation between the motor position and the output modulation
pattern. When a certain position of the motor has been reached, indicated by the
sampled Hall sensor inputs (the Hall pattern), the next, pre-determined Modulation
pattern has to be output. Because of different machine types, the modulation pattern for
driving the motor can vary. Therefore, it is wishful to have a wide flexibility in defining the
correlation between the Hall pattern and the corresponding Modulation pattern.
The CAPCOM6 offers this by having a register which contains the actual current Hall
pattern (CURH), the next expected Hall pattern (EXPH) and the corresponding output
pattern (MCMP). A new Modulation pattern is output when the sampled Hall inputs
match the expected ones (EXPH). To detect the next rotation phase (segment for block
commutation), the CAPCOM6 monitors the Hall inputs for changes. When the next
expected Hall pattern is detected, the next corresponding Modulation pattern is output.
To provide for noise immunity (to a certain extend), the CAPCOM6 offers the possibility
to introduce a sampling delay for the Hall inputs. In addition, it compares the sampled
Hall signals to the current Hall pattern (CURH) to provide for some tolerance in case of
short spikes.
For the Hall and Modulation patterns, a double-register structure is implemented. While
register MCMOUT holds the actually used values, its shadow register MCMOUTS can
be loaded by software from a pre-defined table, holding the appropriate Hall and
Modulation patterns for the given motor control.
A transfer from the shadow register into register MCMOUT can take place when a
correct Hall pattern change is detected, that is, when the sampled Hall pattern matches
the expected one. Software can then load the next values into register MCMOUTS. It is
also possible by software to force a transfer from MCMOUTS into MCMOUT.
User’s Manual
CAPCOM6_X, V2.0
18-50
V2.1, 2004-03