GC5018_06 Datasheet, PDF (47/134 Pages) Texas Instruments – 8-CHANNEL WIDEBAND RECEIVER

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GC5018
8-CHANNEL WIDEBAND RECEIVER
SLWS169A – MAY 2005 – REVISED NOVEMBER 2005
Table 4-1. Different Sync Modes Available
SYNC SELECT CODE
000
001
010
011
100
101
110
111
RECEIVE SYNC SOURCE
rxsync_a
rxsync_b
rxsync_c
rxsync_d
ddc sync counter terminal count
ddc sync triggered by s/w oneshot (register bit)
0 (always off)
1 (always on)
Table 4-2 and Table 4-3 summarizes the blocks which have functions that can be synchronized using the
above eight sync source options.
Sync Name
sync_ddc_counter
sync_ddc
sync_rxsync_out
sync_adc_fifo
sync_tst_decim
sync_recv_pmeterX
sync_ragc_interval_X
sync_ragc_freeze_X
sync_ragc_clear_X
Table 4-2. Receive Common Syncs
Purpose
Initializes the receive sync counter
Initializes the receive ADC interface and clock generation circuits
selects sync signal to be output on the rx_sync_out pin.
Initializes the input and output pointers in the ADC fifo circuits.
Initializes the testbus decimation counter.
Initializes the rxin power meters. {X = 0,1,2 or 3}
Initializes the rxin receive AGC timers. {X = 0,1,2 or 3}
rxin receive AGC freeze mode control. {X = 0,1,2 or 3}
Initializes the receive AGC error accumulator. {X = 0,1,2 or 3}
Sync Name
sync_ddc_tadj
sync_ddc_tadj_reg
sync_ddc_nco
sync_ddc_freq
sync_ddc_phase
sync_ddc_dither
sync_ddc_cic
sync_ddc_pmeter
sync_ddc_gain
sync_ddc_agc
sync_ddc_agc_freeze
sync_ddc_serial
Table 4-3. DDC Channel Syncs
Purpose
Selects zero stuff moment in the tadj fine adjustment section.
Updates the tadj output pointer register delay in the tadj coarse adjustment section.
Resets the NCO accumulator.
Updates the NCO freq registers.
Updates the NCO phase register.
Initializes the NCO dither circuits.
Selects the CIC decimation moment.
Initializes the receive channel power meters.
Updates the DDC channel AGC gain registers
Initializes the AGC accumulator.
AGC freeze mode control.
Initializes the receive serial interface.
A 32-bit general purpose timer is included in the synchronization function. The timer loads the user
programmed terminal count on a sync event, and counts down to zero using rxclk. The width of the
terminal count pulse can also be programmed up to rxclk cycles. The timers output can be used as a sync
source for any other circuits requiring a sync if desired, and can also be routed to the rx_sync_out pin.
GC5018 GENERAL CONTROL
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