ISL5416_14 Datasheet, PDF (55/71 Pages) Intersil Corporation – Four-Channel Wideband Programmable

ISL5416
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TABLE 76. LEAP COUNTER (IWA = *016h) RESET STATE = 0x00000000h
FUNCTION
LEAP COUNTER PRELOAD.
When the leap counter reaches zero, it resets the phase accumulators in NCO1 and NCO2 to zero (if enabled). Because some
frequencies cannot be represented exactly by the NCO control word, this function is provided to zero out any error that builds up due
to the limited NCO resolution. Load with the desired number of clocks between resets minus 1. Note that the ceiling function should
be used when computing the NCO frequency control words so that the NCOs build up a positive phase error and phase accumulator
carries are not suppressed.
TABLE 77. RESAMPLER FREQUENCY/PHASE UPDATE STROBE (IWA = *017h) RESET STATE = INACTIVE
N/A
FUNCTION
N/A STROBE. A write to this location transfers the contents of IWA = *011/*012h and IWA = *013/*014h holding registers to the active
resampler NCO frequency registers. The transfer can also be caused by a SYNCInX signal (see IWA = *000h).
TABLE 78. CHANNEL SOFT RESET (IWA = *018h) RESET STATE = INACTIVE
N/A
FUNCTION
N/A SOFT RESET. A write to this location generates a soft reset of the channel. This clears the slave registers of master/slave pairs and
stops processing in the channel.
TABLE 79. UPDATE DATA PATH CONTROL REGISTER (IWA = *019h) RESET STATE = INACTIVE
N/A
FUNCTION
N/A STROBE. A write to this location updates the active data path control register from its holding register. The transfer can also be
caused by a SYNCInX signal (see IWA = *000h). The active register is cleared on reset, disabling channel processing, so this update
is used to synchronously start the channel processing.
TABLE 80. ADVANCE (IWA = *01Ah) RESET STATE = INACTIVE
N/A
FUNCTION
N/A STROBE. A write to this location repeats one sample at the output of the CIC. Should only be used if there is sufficient overhead for
processing an extra sample.
Locations IWA = *01A and *01B delete or repeat a sample at
the input to FIR1 to shift the system timing. These locations
should not be used if the IHBF or re-sampler is enabled.
TABLE 81. RETARD (IWA = *01Bh) RESET STATE = INACTIVE
N/A
FUNCTION
N/A STROBE. A write to this location deletes one sample at the output of the CIC.
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TABLE 82. FIR 1 COEFFICIENTS (32 x 20) (IWA = *100h THRU *11Fh) RESET STATE = INACTIVE
FUNCTION
UNUSED.
COEFFICIENTS. Twos complement -524287 to +524287 (-524288 not allowed). +524288 would be unity gain.
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TABLE 83. FIR 2 COEFFICIENTS (64 x 20) (IWA = *200h THRU *23Fh) RESET STATE = UNDEFINED
FUNCTION
UNUSED.
COEFFICIENTS. Twos complement -524287 to +524287 (-524288 not allowed). +524288 would be unity gain.
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