Motorola MPC823e Reference Manual page 495

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.
ADDRESS NAME
Half-word 1 I
Half-word 2 K
Half-word 3 CBASE
Half-word 4 M
Half-word 5 XYPTR
Half-word 6 N
Half-word 7 RES
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.
0 1 2
S 0 W
OFFSET + 0
OFFSET + 2
MOTOROLA
Table 16-8. FIR1 Parameter Packet
Number of Iterations
Number of TAPs-1. The number of taps must be a multiple of four
Filter Coefficients Vector Base Address Pointer
Samples Buffer Size-1. The minimum sample buffer size is 8 (4 samples)
Pointer to a structure composed of the input sample data pointer and the output
buffer pointer
Output Buffer Size-1. The minimum output buffer size is 4 (2 outputs)
Reserved
3 4 5 6 7
I 0 1 10
I=3 (THREE ITERATIONS)
MPC823e REFERENCE MANUAL
Communication Processor Module
DESCRIPTION
8 9 10 11 12
1 0 0
13 14 15
00001
16-41