AN2108 Freescale Semiconductor / Motorola, AN2108 Datasheet - Page 20

• Manufacturer Part Number: AN2108
• Description: AN2108 Programming the DSP56307/DSP56311 EFCOP in C Using Taskings Tool Suite
• Manufacturer: Freescale Semiconductor / Motorola

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Application Examples
FDBA+FCNT
FDBA+1
FDBA
FDBA +1
Figure 8 shows the EFCOP data memory in initialized data mode. Although the FDM contains previous
memory values, the initialization mode fills the memory by the amount specified in the counter register,
FCNT, before the EFCOP starts calculating the first output sample. That is, the first FCNT-1 samples are
input before any filtering calculation is performed.
Figure 9 shows the EFCOP Data memory in non-initialized data mode: as soon as the first data samples
are written into FDIR, the EFCOP starts processing. If this mode is used, it is often worth initializing the
initial data samples (i.e. “value”) in FDM to zero.
Three application examples illustrating the use of the EFCOP are presented in this section, along with the
C source code for each application:
Application Examples
•
•
•
A Finite Impulse Response (FIR) filter
An Adaptive FIR filter using the Least Mean Square (LMS) algorithm
The Residu function from the Enhanced Full Rate (EFR) vocoder (an FIR filtering process)
Four Input Samples
FDM
Value
Value
Value
Value
Value
Value
Value
Value
FDBA+FCNT
Figure 9. EFCOP Data Memory in Non-initialized Data Mode
Figure 8. EFCOP Data Memory in Initialized Data Mode
Programming the DSP56307/DSP56311 EFCOP in C
FDBA
FDBA+FCNT
FDBA
FDBA +1
Freescale Semiconductor, Inc.
Four Input Samples
For More Information On This Product,
FDIR
FDI
FDI
FDI
FDM
Value
Value
Value
Value
Value
Value
Value
Value
Go to: www.freescale.com
FDM
x(k)
x(k-1)
x(k-3)
Value
Value
Value
Value
x(k-2)
Input Samples
FDBA+FCNT
FDBA
FDBA+1
FDBA+FCNT
FDIR
FDI
FDI
FDI
FDBA
FDBA+1
FDIR
FDI
FDI
FDI
FDM
x(k)
x(k-1)
x(k-3)
Value
Value
Value
Value
x(k-2)
FDM
x(k)
x(k-1)
x(k-3)
x(k-4)
x(k-5)
x(k-6)
x(k-7)
x(k-2)
Automatic
Transfer
processing
Data
received by FDM,
EFCOP starts
starts processing
Initialization
completed,
FDM
EFCOP