
AD9952
Rev. B | Page 16 of 28
CONTROL REGISTER BIT DESCRIPTIONS
Control Function Register 1 (CFR1)
The CFR1 bits control the functions, features, and modes of the
AD9952. The functionality of each bit is detailed below.
CFR1 [31:27]: Not Used
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 operation.
Each amplitude sample sent to the DAC is multiplied by the
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 causes the output scalar to ramp up from zero
scale to the amplitude scale factor at a rate determined by the
amplitude ramp rate. Toggling the OSK pin low causes the
output to ramp down from the amplitude scale factor to zero
section).
CFR1 [23]: Automatic Synchronization Enable Bit
CFR1 [23] = 0 (default). The automatic synchronization feature
of multiple AD9952s is inactive.
CFR1 [23] = 1. The automatic synchronization feature of
multiple AD9952s is active. The device synchronizes its internal
synchronization clock (SYNC_CLK) to align to the signal
CFR1 [22]: Software Manual Synchronization of Multiple
AD9952s
CFR1 [22] = 0 (default). The manual synchronization feature is
inactive.
CFR1 [22] = 1. The software controlled manual synchronization
feature is executed. The SYNC_CLK rising edge is advanced by
one SYNC_CLK cycle and this bit is cleared. To advance the
rising edge multiple times, this bit needs to be set for each
CFR1 [21:14]: Not Used
CFR1 [13]: Auto-Clear Phase Accumulator Bit
CFR1 [13] = 0 (default). The current state of the phase
accumulator remains unchanged when the frequency tuning
word is applied.
CFR1 [13] = 1. This bit synchronously clears the phase
accumulator automatically (by loadings 0s) for one cycle upon
reception of an I/O UPDATE signal.
CFR1 [12]: Sine/Cosine Select Bit
CFR1 [12] = 0 (default). The angle-to-amplitude conversion
logic employs a COSINE function.
CFR1 [12] = 1. The angle-to-amplitude conversion logic
employs a SINE function.
CFR1 [11]: Not Used
CFR1 [10]: Clear Phase Accumulator
CFR1 [10] = 0 (default). The phase accumulator functions as
normal.
CFR1 [10] = 1. The phase accumulator memory elements are
cleared and held clear until this bit is cleared.
CFR1 [9]: SDIO Input Only
CFR1 [9] = 0 (default). The SDIO pin has bidirectional
operation (2-wire serial programming mode).
CFR1 [9] = 1. The serial data I/O pin (SDIO) is configured as
an input only pin (3-wire serial programming mode).
CFR1 [8]: LSB First
CFR1 [8] = 0 (default). MSB first format is active.
CFR1 [8] = 1. The serial interface accepts serial data in LSB-first
format.
CFR1 [7]: Digital Power-Down Bit
CFR1 [7] = 0 (default). All digital functions and clocks are active.
CFR1 [7] = 1. All non-I/O digital functionality is suspended,
lowering the power significantly.