Decimation Filter
Freescale Semiconductor
28-49
PXR40 Microcontroller Reference Manual, Rev. 1
4. The module is ready to receive data and perform a filtering function.
5. If the input data source is an eQADC, these additional steps must be executed:
a) Configure and enable the eQADC converter to transfer results to the filter.
b) Configure and enable the eQADC commands to transfer filtered results to desired RFIFO.
c) Configure and enable a DMA channel or CPU interrupt handler to transfer result from RFIFO
to memory.
6. If the input data source is the CPU/DMA, configure a CPU interrupt handler or polling software to
input unfiltered data and retrieve the filter data.
28.5.2.1
Use Case 1 - Normal mode, ADC conversion and filtering.
The input to Filter A is from an ADC conversion result.
Filter A is configured as a 4rd order low pass IIR.
The output from the filter is routed to RFIFO5 and transferred to memory by the DMA.
Decimation is not enabled.
Saturation is enabled.
28.5.2.1.1
DECFILT_A_MCR — Module Configuration Register settings
Enable IIR Filter type: FTYPE=1
Scale coefficients to a range of +1 to -1: SCAL=8
Enable saturation of filter output result: SAT=1
Select ‘normal” mode, to transfer data from ADC through filter, to RFIFO: IO_SEL[1]=0
Select no decimation: DEC_RATE=0
28.5.2.1.2
DECFILT_A_COEFn
Write the filter coefficients given in
DECFILT_A_COEF0 = 0x005AB5
DECFILT_A_COEF1 = 0x001240
DECFILT_A_COEF2 = 0x008277
DECFILT_A_COEF3 = 0x001240
DECFILT_A_COEF4 = 0x005AB5
DECFILT_A_COEF5 = 0x2B29E6
DECFILT_A_COEF6 = 0xCC414E
DECFILT_A_COEF7 = 0x1EB97D
DECFILT_A_COEF8 = 0xF8546A
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
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Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
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