The real-time VOP signal interface enables the RF-DAC output power to be adjusted from the PL. The process for updating the output power is shown below.
When the dacX_vop_busy output for the tile is
Low the update input can be asserted together with the desired VOP code. The VOP code is
a 10-bit value indicating the desired full scale current setting. In AC coupled mode,
the VOP code range is between 16 and 895. In DC coupled mode, the VOP code range is
between 112 and 703. The minimum VOP current is 1400 uA. Multiple slices in the same
tile can be updated simultaneously by asserting their update inputs at the same time.
The VOP code should be held on the dacXY_vop_code input
until the process has completed. The busy signal is asserted during the update process
and during tile start up.
The done output (dacXY_vop_done) is asserted
when the VOP update has completed successfully. The maximum jump allowed between two VOP
updates is approximately ±10% of the current VOP value in mA. If a larger jump is
requested, the registers in the converter will not be written and the done signal will
not be asserted. The API can be used to set the correct VOP value if a larger jump is
required.
When more than one RF-DAC channel is modified at the same time the
dacXY_vop_done signal for each channel is asserted when the VOP
update for that channel has completed. The dacX_vop_busy signal remains
high until all channels have been updated. An example where channels 0 and 1 in
converter 0 are updated simultaneously is shown below.
