![Freescale Semiconductor PXR4030 Скачать руководство пользователя страница 1139](http://html1.mh-extra.com/html/freescale-semiconductor/pxr4030/pxr4030_reference-manual_23306601139.webp)
Decimation Filter
Freescale Semiconductor
28-25
PXR40 Microcontroller Reference Manual, Rev. 1
28.3
Functional Description
The following subsections describe the functional operation of a single block and apply to all Decimation
Filter blocks on the device.
28.3.1
Decimation Filter Input
The Decimation Filter receives input data from either the an eQADC block, or from the CPU using the
memory mapped DECFILT_x_IB register. The data source is selected by the
DECFILT_x_MCR[IO_SEL[1]] bit. Note that when the Decimation Filters are cascaded, filters other than
the head filter receive input from the adjacent filter. See
, for more
information on cascade operation.
An interrupt or DMA request can be generated when the input buffer is empty, and the input data source
is the CPU or DMA. A DMA request is generated when the DECFILT_x_MCR[DSEL] = 1, and the input
buffer becomes empty. If DMA is not enabled, an interrupt is generated by setting the
DECFILT_x_MCR[IBIE] = 1. If both an interrupt and DMA request are enabled, the DMA takes
precedence.
An interrupt can also be generated when the input buffer is written with a new value. This interrupt is
enabled by the DECFILT_x_MCR[IDEN] bit. When enabled and data is written to the filter input buffer,
the DECFILT_x_MSR[IDF] bit is set. The IDF flag remains set, even after the input data has been
consumed by the filter and the buffer is free, until IDF is cleared by software write to the IDFC bit.
Section 28.3.12, Interrupts and DMA Overview
, for more information on interrupt and DMA requests.
28.3.1.1
Input Buffer Overrun
An input overrun occurs when the input buffer is holding input data and new data is received by the filter.
See
Section 28.3.1, Decimation Filter Input
, for details of the input buffer. When the decimation filter is
idle (DECFILT_x_MSR[BSY] = 0) the filter can receive two consecutive input buffer writes without input
overrun. Input buffer overrun is detected and flagged by the DECFILT_x_MSR[IVR] bit. The overrun
interrupt is enabled by the DECFILT_x_MCR[ERREN] bit.
The input buffer overrun can occur only in the following cases:
•
When the input buffer has sample data to be processed but the filter is busy and another input (data
or timestamp) is received.
•
When the input buffer has a timestamp, the internal timestamp register is loaded and the next input
data is received.
As an example of the input data sequence, assume that the filter is enabled and not busy, and all registers
are empty. Then a word of sample data is received followed by a timestamp and another word of sample
data. No input overrun occurs in this case, because the first sample is immediately transferred to the tap
input register, the timestamp is immediately transferred to the internal timestamp storage register, and the
second sample can be held in the input buffer until the end of the processing of the first sample data by the
filter. The input overrun may occur if more input is received before the end of the processing, or if the filter
is busy at the beginning of the received sequence.
Содержание PXR4030
Страница 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Страница 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Страница 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Страница 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Страница 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 158: ...Power Management Controller PMC 5 26 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL 6 24 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 278: ...System Integration Unit SIU 7 96 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 280: ...System Information Module PXR40 Microcontroller Reference Manual Rev 1 8 2 Freescale Semiconductor...
Страница 300: ...Boot Assist Module BAM 9 20 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 346: ...Interrupts and Interrupt Controller INTC 10 46 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 352: ...General Purpose Static RAM SRAM 11 6 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 432: ...Core e200z7 Overview PXR40 Microcontroller Reference Manual Rev 1 13 44 Freescale Semiconductor...
Страница 460: ...Peripheral Bridge PBRIDGE 15 16 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 478: ...Memory Protection Unit MPU 16 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 496: ...Error Correction Status Module ECSM 17 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 524: ...Periodic Interrupt Timer PIT_RTI 20 12 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 740: ...FlexRay Communication Controller FLEXRAY 22 156 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 928: ...Deserial Serial Peripheral Interface DSPI 25 68 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 982: ...Enhanced Serial Communication Interface eSCI 26 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1114: ...Enhanced Queued Analog to Digital Converter EQADC 27 132 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1262: ...Enhanced Time Processing Unit eTPU2 29 94 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1399: ...Nexus Development Interface NDI Freescale Semiconductor 31 83 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1400: ...Nexus Development Interface NDI 31 84 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...