DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
Information Manual
Error Correction Coprocessor (DSP1618/28 Only)
April 1998
14-12
DRAFT COPY
Lucent Technologies Inc.
14.5 Software Architecture
(continued)
14.5.2 ECCP Internal Memory-Mapped Registers (continued)
Control Register (ECON)
The constraint length, code rate, soft/hard decision mode, branch metric select, and soft decision data selection
are set in the control register memory-mapped at address location 0x401. The bit allocation of the control register
is the following.
Constraint Length: The constraint length (L) sets the number of states in the Viterbi decoding process to
2
L – 1
. The constraint length sets the number of bits in the generating polynomials for convolutional decoding and
the number of complex channel estimate FIR taps for MLSE equalization. The constraint length also determines
the effective length of the traceback shift register and the traceback RAM used to store the survivor paths.
Three bits in the control register set the constraint length for convolutional decoding or MLSE equalization. For
hard decision convolutional decoding, constraint lengths from 2 to 7 are supported. The hard decision MLSE
equalization is possible for constraint lengths from 2 to 6. For soft decision convolutional decoding or MLSE
equalization, constraint lengths from 2 to 6 are supported. This constraint length field is defined in the following
table.
0x40E—F
Minimum Accumulated Cost Register
MACH
MACL
0x040E
Bits 15:8 are zero.
Bits 7:0 are the upper byte of the minimum
accumulated cost.
0x040F
Bits 15:0 are the lower 2 bytes of the minimum
accumulated cost.
0x410
Traceback Shift Register
TBSR
Traceback shift register (TBSR)
Bits 7:0 are TBSR.
Bits 15:8 are reserved.
0x411—0x7FF
Reserved Registers
Reserved
Table 14-5. Control Fields of the Control Register
ECON Bits
15
14—12
11
10—8
7—3
2
1
0
Function
Reserved Constraint Length Reserved
Code Rate
Reserved
SH
MAN
SD
Bits
ECON(14—12)
Constraint
Length
# of PS/NS
Registers
000
001
010
011
100
101
2
3
4
5
6
7
2
4
8
16
32
64
110
Reserved
111
Reserved
Table 14-4. Memory-Mapped Registers (continued)
Address
Register
Register Bit Field
Содержание DSP1611
Страница 18: ...Chapter 1 Introduction...
Страница 27: ...Chapter 2 Hardware Architecture...
Страница 52: ...Chapter 3 Software Architecture...
Страница 116: ...Chapter 4 Instruction Set...
Страница 154: ...Chapter 5 Core Architecture...
Страница 176: ...Chapter 6 External Memory Interface...
Страница 208: ...Chapter 7 Serial I O...
Страница 237: ...Chapter 8 Parallel I O DSP1617 Only...
Страница 261: ...Chapter 9 Parallel Host Interface PHIF DSP1611 18 27 28 29 Only...
Страница 275: ...Chapter 10 Bit I O Unit...
Страница 284: ...Chapter 11 JTAG Test Access Port...
Страница 306: ...Chapter 12 Timer...
Страница 313: ...Chapter 13 Bit Manipulation Unit...
Страница 325: ...Chapter 14 Error Correction Coprocessor DSP1618 28 Only...
Страница 350: ...Chapter 15 Interface Guide...
Страница 367: ...Appendix A Instruction Encoding...
Страница 379: ...Appendix B Instruction Set Summary...
Страница 381: ...aD extractz aS IM16 B 52 aD insert aS arM B 53 aD insert aS IM16 B 54 aD aS aaT B 55...
Страница 437: ...Index...