GC5328 Datasheet, PDF (8/27 Pages) Texas Instruments – GC5328 Low-Power Wideband Digital Predistortion Transmit Processor

GC5328
SLWS218A – OCTOBER 2009 – REVISED OCTOBER 2009
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HOST UHPI
INTERFACE
Multiplex
Address
Half Data
UHPI
DSP RST
BOOTMODE
DSP JTAG
INTROUT
INTROUT(2)
Note: One DSP is
shared With
GC532xs
EMIF Addr
Cntl SDRAM
TI6727
DSP
EMIF Data
r
e
s
EMIF Addr
Cntl GC5322
Inv
RDB, CS2[]
GPIO
Ant
SelCode
CS2-1
SDRAM
UPDATA[]
UPADDRESS[]
and CNTL CS2-2
To/From
Other GC5322
First GC532x
UPDATA[]
INTROUT
UPADDRESS[]
and CNTL
Figure 7. 6727 DSP to GC5328 EMIF Interface
INTROUT
B0374-01
CAPTURE BUFFERS (SCB)
The GC5328 has two capture buffers of 4096 complex words. The capture buffers are normally used to capture
the Tx reference signal and the feedback output signal. Capture buffer A can capture:
• The TX reference from the DPD after the circular hard limiter
• The feedback output; this represents the waveform as seen by the PA.
• The error output
• Testbus(31:16)
• QRD error output
Capture buffer B can capture:
• The TX reference from the DPD after the circular hard limiter
• The feedback output; this represents the waveform as seen by the PA.
• The error output
• Testbus(15:0)
Standard capture mode – The capture buffers can be armed to collect the 4K complex samples after a
programmable delay following a sync event.
Smart capture mode – There are two trigger conditions that combine the number of samples greater than a
threshold; these are used to find a number of peak events while the transmit signal is above a threshold. In this
case, the magnitude and magnitude-squared of the signal are compared against a threshold and counted. If the
capture buffer finds the trigger condition, the capture logic captures the programmed capture-buffer depth after
the trigger. This is a combination of DSP software and the GC5328 hardware.
NOTE
Capture buffer A has a special mode to source data for diagnostic testing.
The DSP host-interface software has a function to select and get capture-buffer data.
The complex data is then passed from the GC5328 to the EMIF bus, to the DSP, and
back to the host processor.
The DSP host software has a signal-power monitoring function. This uses the
capture-buffer data to perform special monitoring, power measurement, and error
measurements.
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