Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-73
DSP
COMMUNICATION
16
PROCESSOR MODULE
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 16-19. WADD Functions
A B FUNCTION
0≤ α ≥11-α Linear Interpolation
a 0 y(n) = αx (n) Scalar Multiply
1 -1 y(n) = x
1
(n) - x
2
(n) Vector Subtract
Table 16-20. DSP Functions Execution Times
FUNCTION EXECUTION TIME
FIR1 53 + 20 ∗ (Ι - 1) + 1.25 ∗ Ι ∗ (K+1)
FIR2 47 + 17 ∗ (Ι -1) + 3 ∗ Ι ∗ (K+1)
FIR3 44 + 14 ∗ (Ι - 1) + 4 ∗ Ι ∗ (K+1)
FIR5 44 + 14 ∗ (Ι - 1) + 5 ∗ Ι ∗ (K+1)
FIR6 50 + 20 ∗ (Ι - 1) + 3 ∗ Ι ∗ (K+1)
IIR 44 + 11 ∗ Ι
MOD 44 + 7 ∗ Ι
DEMOD 47 + 14 ∗ Ι
LMS1 42 + 7 ∗ (K+1)
LMS2 42 + 7 ∗ (K+1)
WADD 46 + 7 ∗ Ι
NOTES:
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.