MPC563XM Reference Manual, Rev. 1
1116
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Figure 25-1. Decimation Filter Block Diagram
25.2.2
Features
The Decimation Filter Block includes these distinctive features:
•
Implements a selectable IIR filter or FIR filter
— Input/output with 16 bits (fixed point) for 2-complement signed values
— Internal taps with 16 bits (feed-forward portion) and 24 bits (feedback portion) resolutions
(fixed point) for 2-complement signed value
— 24 bits programmable filter coefficients (fixed point) for 2-complement signed value
— Intermediary accumulator with 51 bits (fixed point)
— Convergent rounding methodology
— 2-complement overflow or saturation selection
— Filter takes about 66 clock cycles to filter an input data
•
Implements a local sky-blue interface to a master block as the eQADC block
•
Use of parameterized RTL code as much as possible to allow to remove unwanted features
•
Sky-Blue interface to SoC
•
Filter taps access for debug
•
Software Reset and flush
Control
Logic
PSI
PSI
Coefficient
register file
SoC Sky-Blue line
Filter TAP
registers
MAC
dec-counter
rxdata
filter tap result
sample
decimated
tx en
new sam
p
le/con
trol fi
el
d
clear/load
select
coefficient
data
en
data in 1
data in 2
decimated
intermediary
result
result
by pass data path
tap data
mac done
done
enable/clear
counter
en
data
by-pass sel
PSI Sky-Blue line
Rx
Tx