MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1115
Preliminary—Subject to Change Without Notice
Chapter 25
Decimation Filter
25.1
Information Specific to This Device
This section presents device-specific parameterization and customization information not specifically
referenced in the remainder of this chapter.
25.1.1
Device-Specific Features
•
There are no specific features for this device.
25.2
Introduction
This document describes the requirements and architecture for the implementation of a Decimation Filter
stand alone block to treat fixed point data as the conversion samples generated by the eQADC block.
25.2.1
Overview
The Decimation filter is dedicated to decimate fixed point digital samples as the conversion results of an
eQADC block (master block). A dedicated PSI (Parallel Side Interface) Sky-Blue interface provides
bidirectional communication between the master block and the filter. Another Sky-Blue interface is also
provided thus allowing for setting up the filter parameters and the configuration registers.
The Decimation Filter receives data samples from the master block (for example, the eQADC) in the PSI
RX sub-block. Each sample comes together with an identifier called tag and with some commands. The
input information is decoded by the PSI RX and Control Logic sub-blocks. In case of receiving a filtering
command, the data is transferred to the Filter Tap Registers sub-block and they are processed by the filter
using the MAC, the Coefficient Register and the Control Logic sub-blocks. After this step, the result can
be returned to the master block by the PSI TX sub-block. This result is accompanied with the
corresponding tag information that works as an address for the data.
Therefore, the Decimation Filter works as a slave block in this second sky-blue line and there is a local
master block to send and read data like the eQADC block in the application example of item 5.2
Application Information.
All signals in the interface are generated in the ipg_clk system clock domain.
is the block diagram for the decimation filter.