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12.5.1
Terminology Used in this Section
Compute
Perform all calculations to determine one filter output F(n) for a specific
set of input data samples.
Get
Write a data word to the FCOP Data Memory buffer (FDM) via FDIR.
D(n), DR(n):
Real data sample number n.
DI(n)
Imaginary data sample number n.
H(n), HR(n)
Real filter coefficient number n.
HI(n)
Imaginary filter coefficient number n.
F(n), FR(n)
Real output result number n.
FI(n)
Imaginary output result number n.
#filter_count
Number of coefficient values in the FCOP coefficients Memory bank
FCM (equals contents of FCNT register plus 1).
Note:
Some items on this list have two forms, for example D(n), D=R(n). In such cases the D(n) form is
used when only real values are present, and the DR(n) form is used when complex values are
present.
12.5.2
Input DMA Activation
The DMA for input data transfers can be activated only after enabling FCOP (FEN set)
and after the core has initialized the coefficients bank through FCIR. Then, the DMA
input channel can be enabled in order to start transferring data whenever there are free
locations in the input FIFO, while the FCOP state machine grabs data words from that
FIFO whenever required.The FCOP state machine starts computation as soon as both
coefficient and data banks complete the initialization phase (according to #filter_count
value).
A good practice is to program the input data DMA channel for single word transfer or
line of 2, 3, or 4 word transfer (since the input buffer FIFO depth is 4), triggered by the
FDIBE bit in FCSR.
MOTOROLA
DSP56305 User's Manual
Filter Co-Processor
Operation Modes
12-15
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