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16.3.4.11.4 Application Example. By specifying different values, several functions can be
implemented as shown in the table below.
16.3.4.12 THE DSP EXECUTION TIMES. A function's execution time is a linear function of
the number of taps and iterations specified for that function. It includes overhead for
context-switch, function descriptor handling, and initialization. Table 16-20 lists the
execution time for each of the DSP functions.
Table 16-20. DSP Functions Execution Times
FUNCTION
DEMOD
WADD
NOTES:
MOTOROLA
Table 16-19. WADD Functions
A
B
0≤ α ≥1
1-α
a
0
1
-1
y(n) = x
53 + 20 ∗ (Ι - 1) + 1.25 ∗ Ι ∗ (K+1)
FIR1
47 + 17 ∗ (Ι -1) + 3 ∗ Ι ∗ (K+1)
FIR2
44 + 14 ∗ (Ι - 1) + 4 ∗ Ι ∗ (K+1)
FIR3
44 + 14 ∗ (Ι - 1) + 5 ∗ Ι ∗ (K+1)
FIR5
50 + 20 ∗ (Ι - 1) + 3 ∗ Ι ∗ (K+1)
FIR6
IIR
MOD
LMS1
LMS2
1.
Add 1 clock for wrap, 5 clocks for stop, and 4 clocks for
interrupt.
2.
i = number of iterations.
3.
k+1 = number of taps.
MPC823e REFERENCE MANUAL
Communication Processor Module
FUNCTION
Linear Interpolation
y(n) = αx (n) Scalar Multiply
(n) - x
(n) Vector Subtract
1
2
EXECUTION TIME
44 + 11 ∗ Ι
44 + 7 ∗ Ι
47 + 14 ∗ Ι
42 + 7 ∗ (K+1)
42 + 7 ∗ (K+1)
46 + 7 ∗ Ι
16-73
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