Component specific signals, Fft ip core signals in qsys systems, Fft ip core signals in qsys systems -19 – Altera FFT MegaCore Function User Manual
Page 42
Component Specific Signals
The component specific signals.
Table 3-7: Component Specific Signals
Signal Name Directio
n
Size
Description
fftpts_
in
Input
log
2
(maximum
number of
points)
The number of points in this FFT frame. If this value is not
specified, the FFT can not be a variable length. The default
behavior is for the FFT to have fixed length of maximum
points. Only sampled at SOP.
fftpts_
out
Output log
2
(maximum
number of
points)
The number of points in this FFT frame synchronized to
the Avalon-ST source interface. Variable streaming only.
inverse
Input
1
Inverse FFT calculated if asserted. Only sampled at SOP.
Incorrect usage of the Avalon-ST interface protocol on the sink interface results in a error on
source_error
defines the behavior of the FFT when an incorrect Avalon-ST transfer is
detected. If an error occurs, the behavior of the FFT is undefined and you must reset the FFT with
reset_n
.
Table 3-8: Error Handling Behavior
Error
source_
error
Description
Missing
SOP
01
Asserted when valid goes high, but there is no start of frame.
Missing
EOP
10
Asserted if the FFT accepts N valid samples of an FFT frame, but there
is no EOP signal.
Unexpecte
d EOP
11
Asserted if EOP is asserted before N valid samples are accepted.
FFT IP Core Signals in Qsys Systems
When you instantiate your design in a Qsys sytem and target Arria 10 devices, the signals appear as a
single bus:
• In:
• Real
• Imaginary
• Out:
• Real
• Imaginary
UG-FFT
2014.12.15
Component Specific Signals
3-19
FFT IP Core Functional Description
Altera Corporation