Table 12-5 Relationship Of Fdiie And Fdibe; Fcop Decimation (Fdcm)—Fcsr Bit 8 - Motorola DSP56305 User Manual

12.4.6.3 FCOP Decimation (FDCM)—FCSR Bit 8
The FCOP Decimation (FDCM) read/write control bit determines the decimation
function. When FDCM is set, decimation by 2 occurs and when FDCM is cleared, no
decimation occurs. No decimation is chosen for non-oversampled data while decimation
by 2 is used for 2× oversampled data. FDCM should only be changed when FCOP is in
the FCOP individual reset state (FEN = 0), otherwise improper operation may result.
FDCM is cleared by hardware or software reset. For more details about the effect of
FDCM on the module's operation, refer to Section 12.5.
12.4.6.4 FCOP Data Input Interrupt Enable (FDIIE)—FCSR Bit 10
The FCOP Data Input Interrupt Enable (FDIIE) read/write control bit, when set, enables
the Data Input Buffer Empty Interrupt. When FDIIE is cleared, the Data Input Buffer
Empty Interrupt is disabled, and the FDIBE status bit should be polled to determine if
FDIR is empty. The following table describes the effect of the possible combined states of
FDIIE and FDIBE:
FDIIE FDIBE
Data Input Buffer Empty Interrupt
0 0
Register (FDIR) is not empty. Do not write to FDIR.
0 1 Data Input Buffer Empty Interrupt
Register (FDIR) is empty. DMA write to FDIR possible.
Data Input Buffer Empty Interrupt is
1 0
Register (FDIR) is not empty. Do not write to FDIR.
1 1 Data Input Buffer Empty Interrupt
Register (FDIR) is empty. FCOP requests a Data Input Buffer Empty
Interrupt service from the DSP56300 core. Interrupt write to FDIR is
possible.
DMA transfer is enabled if a DMA channel is activated and allocated for FCOP Data
Input Buffer Empty (FDIBE is set). FDIR should be written either by the interrupt routine
or the DMA transfer, but not both, so it is highly recommended to enable either the
interrupt or DMA, but not both.
MOTOROLA

Table 12-5 Relationship of FDIIE and FDIBE

DSP56305 User's Manual
Filter Co-Processor
Programming Model
Effect
is disabled. FCOP
is disabled. FCOP
enabled. FCOP
is enabled. FCOP
Data Input
Data Input
Data Input
Data Input
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