MC92307 Datasheet, PDF (4/10 Pages) Motorola, Inc – 2K - Samples FFT-Processor

External Interfaces
CLK
DINR
DIN
X0r
X1r
...
Xir
X(i+1)r
...
X0q
X1q
...
Xiq
X(i+1)q
...
FFTSTART
DOUTR
Z(N-i)r
Z(N-i+1)r
...
Z0r
Z1r
...
DOUT
Z(N-i)q
Z(N-i+1)q
...
Z0q
Z1q
...
tion ^SYMSYNC
Figure 3. Data I/O for the Non-multiplexed Mode
a _FFTSTART
m The input of a data block into the FFT device starts with
r _{a pulse of the FFTSTART signal. It must be delivered}
fo ^{together with the real part of the first time domain sam-}
ple and should last 1..2 clock cycles.
In _{DIN [7:0]}
y _{These pins accept the input data with a wordlength of}
r _{8 bit. In the muxed mode first the real part of a sample}
a _{must be provided followed by the imaginary part. In the}
in ^{non-muxed mode only the imaginary part must be deliv-}
ered to DIN. The data format is fixed to 2’s complement.
lim ^{DINR [7:0]}
In the non-muxed mode (NOMUX = H) the real part of
re ^{the input samples is entered into the FFT device via}
these pins (they should be connected to a fixed level if
P _{the muxed mode is used). As the DIN inputs these in-}
puts expect 2’s complement format.
FFT Device -> OFDM Device
SYMSYNC
The start of the output of a FFT block after processing
is indicated by a pulse of the SYMSYNC signal with a
duration of 2 clock cycles. It is delivered together with
the real part of the first output sample.
DOUT [11:0]
These pins deliver the output data of the FFT device in
2’s complement format. In the non-muxed mode
(NOMUX = H) the real part of the samples is followed by
the imaginary part. In the muxed mode only the imagi-
nary parts appears at the DOUT pins.The valid bits are
adjusted using the RES pins, see above.
DOUTR [11:0]
In the non-muxed mode (NOMUX = H) the real part of
the output samples appears at these pins in 2’s comple-
ment format. The wordlength selection by the RES pins
is also valid for DOUTR. If the non-muxed mode is used
these pins may be left unconnected.
MOTOROLA
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MC92307_DS - 8/12/97