Now the clock router can place a buffer into the specified network,
which divides the network into two parts: from the source to the buffer,
routing occurs through any available PIPs, and after the buffer to the
sink, only through a dedicated global clock network.
This is made specifically for the Tangnano20k where the external
oscillator is soldered to a regular non-clock pin. But it can be used
for other purposes, you just need to remember that the recipient must be
a CLK input or output pin.
The port/network to set the buffer to is specified in the .CST file:
CLOCK_LOC "name" BUFG;
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
To implement unusual IOs that have a dynamically changing configuration
it is convenient to store the switching method in the additional chip
data.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
- minor fixes for pinout saving;
- CST parser taken from generic-based apicula;
- $nextpnr IOB detachment is copied here because it is necessary to copy
attributes from deleted bels.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
