Question
While the device is in RESET is it possible to program any register to any
value other than the default ?
Answer
It is not possible to program the AD9511 while it is in RESET state. This is
because the RESETB pin (or the soft-reset bit) initiates a sequence of events,
one of which is to reload the default values into the register map. So, even if
you write new values into registers while holding RESET_B low, the reset
operation which ensues when you release RESETB will load the default values
(hardwired) into the registers - so the attempted programming will be
ineffective.
It is possible, however, to hold the outputs in a fixed (non-toggling)
condition by holding the SYNCB signal low. First set the FUNCTION pin to act as
SYNCB. Then, pull the FUNCTION pin low. All outputs which are not explicitly
masked, or are divide-by-1 (divider bypassed) will stop toggling and assume a
preset state. Upon releasing SYNCB, the outputs which were stopped will resume
toggling, but synchronized according to their presets.
