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Decimation Filter
MPC5644A Microcontroller Reference Manual, Rev. 6
1174
Freescale Semiconductor
•
Filter taps access for debug
•
Filter initialization (flush) and stabilization (prefill) commands
•
Timestamp support
•
Decimation controlled by an internal counter or from an on-chip independent trigger signal
(triggered output result)
•
Integrator unit accumulates filter output values, signaled or absolute, with 32-bit resolution. The
integrator can be controlled by software or hardware signals.
•
Cascade of 2 or more individual blocks to compose a more complex filter
26.2.3
Modes of operation
This section describes the operation modes of the Decimation Filter. The modes are selected using the
DECFILTER_MCR fields MDIS, FREN, FRZ, ISEL, MIXM, and CASCD (see
Decimation Filter Module Configuration Register (DECFILTER_MCR)
summarized in
.
26.2.3.1
Normal mode
This is the default operational mode of the decimation filter block. It corresponds to the prefill/filter
operation with input data supplied through the PSI slave-bus interface (i.e. its input data is the ADC
conversion result), with output going to the same PSI interface.
26.2.3.2
Standalone mode
Standalone mode differs from normal mode because the input data is not supplied by the master block
through the PSI slave-bus interface. In this case, the data is provided by the central processor using the
device slave-bus interface or DMA interface signals. Once the data is filtered the decimated result is
available in the Output Buffer register. The filter output is also consumed by a CPU or DMA mastering
the same device slave-bus interface. This operation mode can be used to debug the filter stability or to
decimate data in System RAM.
Table 26-2. Operation mode selection
Mode
MDIS
FREN, FRZ
ISEL
MIXM
CASCD
Normal
0
(0, 0)
or
(0, 1)
or
(1, 0)
0
0
00
Standalone
1
0
PSI Input Mixed
0
1
PSI Output Mixed
1
1
Cascade
0 or 1
0
01 or 10 or 11
Freeze
1
1
Freeze mode can also be activated from outside the Decimation Filter, depending on the MCU, if
FREN = 1.
1, 1
X
X
X
Low Power
1
X
X
X
X
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...