Shared-Processing (SP) Mode

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Figure 19. TCP2 Shared Processing Block Diagram

MAP 1: Parity A or

MAP 2: Parity A'

MAP 1: Parity B or

MAP 2: Parity B'

Void input

MAP 1: Systemic or

MAP 2: Interleaved (systematic)

MAP 1: De−interlaced (Apriori 2) or MAP 2: Interleaved (Apriori 1)

MAP decoder unit

MAP 1: Apriori 1 or

Extrinsic saved as apriori

MAP 2: Apriori 2

 

5.1Input Data Format

5.1.1Systematic and Parity Data

The original systematic and parity data is organized as described in Section 4.1.1. The DSP has to split the data for MAP0 and MAP1 as shown in the following figures. The base address must be double-word aligned. Interleaved systematic data (X.) must be calculated by the DSP given the interleaver table (see Section 4.1.2). For big-endian configuration, see Section 7.

Figure 20. Systematic/Parity Data for Rates 1/2, 1/3, 1/4, 1/5, and 3/4

63:62

61:56

55:50

49:44

43:38

37:32

31:30

29:24

23:18

17:12

11:6

5:0

RSVD

SP9

SP8

SP7

SP6

SP5

RSVD

SP4

SP3

SP2

SP1

SP0

Figure 21. EN = 1 (Little-Endian Mode) Rate = 1/2

 

 

Word

 

 

 

 

Word

 

 

 

 

N + 1

 

 

 

 

N

 

 

SP9

SP8

SP7

SP6

SP5

SP4

SP3

SP3

SP3

SP0

0

A1'

0

0

X1

0

0

0

0

X0

 

 

Word

 

 

 

 

Word

 

 

 

 

N + 3

 

 

 

 

N + 2

 

 

SP9

SP8

SP7

SP6

SP5

SP4

SP3

SP3

SP3

SP0

0

A3'

0

0

X3

0

0

0

0

X2

Figure 22. EN = 0 (Big-Endian Mode) Rate = 1/2

 

 

 

Word

 

 

 

 

Word

 

 

 

 

 

N

 

 

 

 

N + 1

 

 

 

SP4

SP3

SP2

SP1

SP0

SP9

SP8

SP7

SP6

SP5

 

0

0

0

A0

X0

0

A1'

0

0

X1

 

 

 

Word

 

 

 

 

Word

 

 

 

 

 

N + 2

 

 

 

 

N + 3

 

 

 

SP4

SP3

SP2

SP1

SP0

SP9

SP8

SP7

SP6

SP5

 

0

0

0

A2

X2

0

A3'

0

0

X3

22

TMS320C6457 Turbo-Decoder Coprocessor 2

 

 

 

 

SPRUGK1–March 2009

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Texas Instruments TMS320C6457 DSP manual TCP2 Shared Processing Block Diagram