+ Add a HDL parameter for the PPS receiver module :
PPS_RECEIVER_ENABLE. By default the module is disabled.
+ Add the CMOS_OR_LVDS_N and PPS_RECEIVER_ENABLE into the CONFIG
register
+ Define a pps_status read only register, which will be asserted, if the free
running counter reach a certain fixed threshold. (2^28) The register can
be deasserted by an incomming PPS only.
The ad_pps_receiver is instantiated at the top of core.
The rcounter is placed into adc/dac_common registers space, at the
address 0x30 (word aligned).
The interrupt mask is placed into adc/dac_common, at the address 0x04
(word aligned). Because the core has an instance of both modules, the
interrupt masks are OR-ed together.
Set the ASYNC_REG property on the bit synchronizer CDC control regs. This
hint to Vivado that the registers are used for CDC purposes.
Also use -datapath_only for the set_max_delay constraints on the CDC data
path to remove the hold time requirement.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>