Motorola MPC860 PowerQUICC User Manual page 938

Part V. The Communications Processor Module
Table 36-21. DEMOD Modulation Table, Input, and Output Buffers (Continued)
36.14.2 DEMOD Function Descriptor
The DEMOD function descriptor is shown in Figure 36-28.
0 1
Offset + 0 S Ñ
Offset + 0x2
Offset + 0x4
Offset + 0x6
Offset + 0x8
Offset + 0xA
Offset + 0xC
Offset + 0xE
The status and control bits (at offset 0x00) are described in Table 36-2. The DEMOD
parameter packet consists of seven 16-bit entries and is described in Table 36-22.
Address Name
Hword 1 I Number of iterations
Hword 2 K Modulation table_size - 1. The minimum modulation table size is 8 (2 sin/cos pairs).
Hword 3 DPTR Pointer to a structure consisting of the modulation table pointer and the AGC constant (real)
Hword 4 M Input buffer_size - 1. The minimum input buffer size is 8 (2 samples).
Hword 5 XYPTR Pointer to a structure composed of the input buffer pointer and the output buffer pointer
Hword 6 N Output buffer_size - 1. The minimum output buffer size is 8 (2 outputs).
Hword 7 Ñ Reserved
36-24
cos q
n
2 3 4 5
W I
Figure 36-28. DEMOD Function Descriptor
Table 36-22. DEMOD Parameter Packet
MPC860 PowerQUICC UserÕs Manual
x(n) real{Y(n-2)}
imaginary{Y(n-1)}
real{Y(n-1)}
imaginary{Y(n)}
real{Y(n)}
6 7 8 9 10
Ñ
I
K
DPTR
M
XYPTR
N
Ñ
Description
11 12 13 14 15
01001
MOTOROLA