This chip is used in the Tangnano9k board.
* all parameters of the rPLL primitive are supported;
* all PLL outputs are treated as clock sources and optimized routing
is applied to them;
* primitive rPLL on different chips has a completely different
structure: for example in GW1N-1 it takes two cells, and in GW1NR-9C
as many as four, despite this unification was carried out and
different chips are processed by the same functions, but this led to
the fact that you can not use the PLL chip GW1N-1 with the old
apicula bases - will issue a warning and refuse to encode primitive.
In other cases compatibility is supported.
* Cosmetic change: the usage report shows the rPLL names without any
service bels.
* I use ctx->idf() on occasion, it's not a total redesign.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* both instances of the new PLLVR type are supported;
* primitive placement is optimized for the use of dedicated PLL clock
pins;
* all 4 outputs of each primitive can use the clock nets (only 5 lines
in total at the same time so far).
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
The dedicated router for clock wires now understands not only the IO
pins but also the rPLL outputs as clock sources.
This simple router sets an optimal route, so it is now the default
router. It can be disabled with the --disable-globals command line flag
if desired, but this is not recommended due to possible clock skew.
Still for GW1N-4C there is no good router for clock wires as there
external quartz resonator is connected via PLL.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
Refactor in order to detect networks that will be routed in a special
mode earlier. This makes it possible to mark the source of such networks
as a global buffer, thereby removing their influence on element
placement.
In addition, timing classes are set for some cells.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
A simple router that takes advantage of the fact that in each cell with
DFFs their CLK inputs can directly connect to the global clock network.
Networks with a large number of such sinks are sought and then each
network is assigned to the available independent global clock networks.
There are limited possibilities for routing mixed networks, that is,
when the sinks are not only CLKs: in this case an attempt is made to use
wires such as SN10/20 and EW10/20, that is, one short transition can be
added between the global clock network and the sink.
* At this time, networks with a source other than the I/O pin are not
supported. This is typical for Tangnano4k and runber boards.
* Router is disabled by default, you need to specify option
--enable-globals to activate
* No new chip bases are required. This may change in the distant future.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
