Fcop Coefficients Input Register (Fcir); Fcop Filter Count Register (Fcnt); Fcop Control/Status Register (Fcsr) - Motorola DSP56305 User Manual

12.4.4

FCOP Coefficients Input Register (FCIR)

The FCOP Coefficients Input Register (FCIR) is a 16-bit write-only register used for
DSP-to-FCOP coefficients transfers. The filter coefficients are written to FCIR and
transferred to the FCOP Coefficients Memory bank (FCM) before starting the filter
processing. The FCIR can be written by the DSP56300 core.
12.4.5

FCOP Filter Count Register (FCNT)

The FCOP Filter Count Register (FCNT) is a 16-bit read/write register used for setting
the filter length (number of filter taps). The actual value written to FCNT register is the
number of coefficient values minus one. The number of coefficient values is actually the
number of locations used in the FCM. For a real FIR filter, the number of coefficient
values is equal to the number of filter taps. For a complex FIR filter, the number of
coefficient values is twice the number of filter taps. The number of taps in FCNT is used
by the FCOP Address Generation logic to supply the correct addressing to the FDM and
FCM memory banks.
The FCOP can only be written to by the core. Write to FCNT before enabling FCOP (by
setting FEN). FCNT should be changed only when FCOP is in the FCOP individual reset
state (FEN = 0), otherwise improper operation may result. The number stored in FCNT is
used by the FCOP Address Generation logic to generate the correct addressing for the
FDM and the FCM.
12.4.6

FCOP Control/Status Register (FCSR)

The FCOP Control/Status Register (FCSR) is a 16-bit read/write register used by the
DSP56300 core to control the main operation modes and to monitor the status of the
module. The FCSR bits are described in the following paragraphs. All FCSR bits are
cleared after hardware and software reset.
MOTOROLA DSP56305 User's Manual
Filter Co-Processor
Programming Model
12-9