Motorola MPC823e - Page 525

Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-71
DSP
COMMUNICATION
16
PROCESSOR MODULE
16.3.4.11.1 Coefficients and Sample Data Buffers. Each input vector is stored in a cyclic
buffer containing M+1 bytes. Each sample is a 16-bit half-word and the newest sample is
stored in the address that follows the previous sample. The output buffer is a cyclic buffer
that contains N+1 bytes. Each output is a 16-bit half-word and the newest output is stored
in the address that follows the previous one.
16.3.4.11.2 WADD Function Descriptor. The WADD function descriptor bit table is
described below.
X
1
INPUT SAMPLES X
2
INPUT SAMPLES OUTPUT
** *
x
1
(n-k+1) * *
*x
2
(n-k+1) *
** *
x
1
(n-2) * Y(n-k+1)
x
1
(n-1) x
2
(n-2) *
x
1
(n) x
2
(n-1) *
x
2
(n) Y(n-2)
Y(n-1)
Y(n)
2K bytes M + 1 bytes N + 1 length buffer
Figure 16-33. WADD Modulation Table and Sample Data Buffers
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
OFFSET + 0
S RES W I RES OPCODE
OFFSET + 2
I
OFFSET + 4
A
OFFSET + 6
B
OFFSET + 8
M
OFFSET + A
XYPTR
OFFSET + C
N
OFFSET + E
RESERVED