AD9954(Rev0) データシートの表示（PDF） - Analog Devices
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AD9954 Datasheet PDF : 36 Pages
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AD9954
Register
Name
(Serial
Address)
Positive
Linear
Sweep
Control
Word
(PLSCW)
(0x08)
Bit Range
<7:0>
<15:8>
<23:16>
<31:24>
(MSB)
Bit 7
<39:32>
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Rising Delta Frequency Tuning Word <7:0>
Rising Delta Frequency Tuning Word <15:8>
Rising Delta Frequency Tuning Word <23:16>
Rising Delta Frequency Tuning Word <31:24>
Rising Sweep Ramp Rate Word <7:0>
Bit 1
(LSB)
Bit 0
Default
Value
OR
Profile
PS0 = 1
PS0 = 1
PS0 = 1
PS0 = 1
PS0 = 1
Control Register Bit Descriptions
Control Function Register No.1 (CFR1)
The CFR1 is used to control the various functions, features,
and modes of the AD9954. The functionality of each bit is
detailed below.
CFR1<31>: RAM Enable Bit
CFR1<31> = 0 (default). When CFR1<31> is inactive, the RAM
is disabled for operation. Either single-tone mode of
operation or linear sweep mode of operation is enabled.
CFR1<31> = 1. If CFR1<31> is active, the RAM is
enabled for operation. Access control for normal operation is
controlled via the mode control bits of the RSCW for the cur-
rent profile.
CFR1<30>: RAM Destination Bit
CFR1<30> = 0 (default). If CFR1<31> is active, a Logic 0 on the
RAM destination bit (CFR1<30> = 0) configures the AD9954
such that the RAM output drives the phase accumulator (i.e.,
the frequency tuning word). If CFR1<31> is inactive,
CFR1<30> is a Don’t Care.
CFR1<30> = 1. If CFR1<31> is active, a Logic 1 on the RAM
destination bit (CFR1<30> = 1) configures the AD9954 such
that the RAM output drives the phase-offset adder (i.e., sets the
phase offset of the DDS core).
CFR1<29:27>: Internal Profile Control Bits
These bits cause the profile bits to be ignored when the RAM is
being used and puts the AD9954 into an automatic profile loop
sequence that allows the user to implement a frequency/phase
composite sweep that runs without external inputs. See the
Internal Profile Control section for more details.
CFR1<26>: Amplitude Ramp Rate Load Control Bit
CFR1<26> = 0 (default). The amplitude ramp rate timer is
loaded only upon timeout (timer == 1) and is not loaded due to
an I/O UPDATE input signal.
CFR1<26> = 1. The amplitude ramp rate timer is loaded upon
timeout (timer == 1) or at the time of an I/O UPDATE input signal.
CFR1<25>: Shaped On-Off Keying Enable Bit
CFR1<25> = 0 (default) Shaped on-off keying is
bypassed.
CFR1<25> = 1. Shaped on-off keying is enabled. When enabled,
CFR1<24> controls the mode of operation for this function.
CFR1<24>: Auto Shaped On-Off Keying Enable Bit (Only Valid
When CFR1<25> Is Active High)
CFR1<24> = 0 (default). When CFR1<25> is active, a Logic 0
on CFR1<24> enables the manual shaped on-off keying opera-
tion. Each amplitude sample sent to the DAC is multiplied by
the amplitude scale factor. See the Shaped On-Off Keying sec-
tion for details.
CFR1<24> = 1. When CFR1<25> is active, a Logic 1 on
CFR1<24> enables the auto shaped on-off keying operation.
Toggling the OSK pin high will cause the output scalar to ramp
up from zero scale to the amplitude scale factor at a rate deter-
mined by the amplitude ramp rate. Toggling the OSK pin low
will cause the output to ramp down from the amplitude scale
factor to zero scale at the amplitude ramp rate. See the Shaped
On-Off Keying section for details.
CFR1<23>: Automatic Synchronization Enable Bit
CFR1<23> = 0 (default). The automatic synchronization feature
of multiple AD9954s is inactive.
CFR1<23> = 1. The automatic synchronization feature of mul-
tiple AD9954s is active. The device will synchronize its internal
synchronization clock (SYNC_CLK) to align to the signal pre-
sent on the sync-in input. See the Synchronizing Multiple
AD9954s section for details.
CFR1<22>: Software Manual Synchronization of Multiple
AD9954
CFR1<22> = 0 (default). The manual synchronization feature is
inactive.
Rev. 0 | Page 18 of 36
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