SPRS945G January 2017 – January 2023 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
PRODUCTION DATA
The C28x with VCU (C28x+VCU) processor extends the capabilities of the C28x fixed-point or floating-point CPU by adding registers and instructions to support the following algorithm types:
Viterbi decoding is commonly used in baseband communications applications. The viterbi decode algorithm consists of three main parts: branch metric calculations, compare-select (viterbi butterfly), and a traceback operation. Table 8-11 lists a summary of the VCU-I performance for each of these operations.
VITERBI OPERATION | VCU CYCLES |
---|---|
Branch Metric Calculation (code rate = 1/2) | 1 |
Branch Metric Calculation (code rate = 1/3) | 2p |
Viterbi Butterfly (add-compare-select) | 2 (1) |
Traceback per Stage | 3 (2) |
CRC algorithms provide a straightforward method for verifying data integrity over large data blocks, communication packets, or code sections. The C28x+VCU can perform 8-, 16-, and 32-bit CRCs. For example, the VCU can compute the CRC for a block length of 10 bytes in 10 cycles. A CRC result register contains the current CRC which is updated whenever a CRC instruction is executed.
Complex math is used in many applications; a few of which are:
The complex FFT is used in spread spectrum communications, as well as many signal processing algorithms.
Complex filters improve data reliability, transmission distance, and power efficiency. The C28x+VCU can perform a complex I and Q multiply with coefficients (four multiplies) in a single cycle. In addition, the C28x+VCU can read/write the real and imaginary parts of 16-bit complex data to memory in a single cycle.
Table 8-12 lists a summary of a few complex math operations enabled by the VCU.
COMPLEX MATH OPERATION | VCU CYCLES | NOTES |
---|---|---|
Add or Subtract | 1 | 32 ± 32 = 32-bit (Useful for filters) |
Add or Subtract | 1 | 16 ± 32 = 15-bit (Useful for FFT) |
Multiply | 2p | 16 × 16 = 32-bit |
Multiply and Accumulate (MAC) | 2p | 32 + 32 = 32-bit, 16 × 16 = 32-bit |
RPT MAC | 2p+N | Repeat MAC. Single cycle after the first operation. |