Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-41
DSP
COMMUNICATION
16
PROCESSOR MODULE
INDEX— Auto-Increment Index
00 = The X (input) pointer is not incremented.
01 = The X (input) pointer is incremented by one sample.
10 = The X (input) pointer is incremented by two samples.
11 = The X (input) pointer is incremented by three samples.
PC— Preset Coefficients Pointer
0 = The coefficients pointer is not preset after each iteration.
1 = The coefficients pointer is preset after each iteration to the CBASE pointer.
OPCODE—Function Operation Code
This field specifies the function to be executed. Table 16-6 contains the value for this field.
16.3.4.1.3 FIR1 Parameter Packet. The FIR1 parameter packet is composed of seven
16-bit half-words and described in the following table.
16.3.4.1.4 Application Example. The FIR1 is used in decimation and RX interpolation. For
example, the following function descriptor structure can be used to implement a 2 to 1
decimation.
Table 16-8. FIR1 Parameter Packet
ADDRESS NAME DESCRIPTION
Half-word 1 I Number of Iterations
Half-word 2 K Number of TAPs-1. The number of taps must be a multiple of four
Half-word 3 CBASE Filter Coefficients Vector Base Address Pointer
Half-word 4 M Samples Buffer Size-1. The minimum sample buffer size is 8 (4 samples)
Half-word 5 XYPTR Pointer to a structure composed of the input sample data pointer and the output
buffer pointer
Half-word 6 N Output Buffer Size-1. The minimum output buffer size is 4 (2 outputs)
Half-word 7 RES Reserved
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
OFFSET + 0
S 0 W I 0 1 10 1 0 0 00001
OFFSET + 2
I=3 (THREE ITERATIONS)
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