Some models have I/O cells that are IOBUFs, and other types (IBUFs and
OBUFs) are obtained by feeding 1 or 0 to the OEN input. This is done
with general-purpose routing so it's best to do it here to avoid
conflicts.
For this purpose, in the new bases, these special cells are of type IOBS
(IOB Simplified).
The proposed changes are compatible with bases of previous versions of
Apycula and do not require changing .CST constraint files.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
- Both the mode used by yosys and all Gowin primitive modes are supported.
- The ALU always starts with a zero slice.
- The maximum length of the ALU chain is limited to one line of the chip.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* A hardwired MUX within each logical cell is used.
* The delay is equal 0.
* No user placement constraints.
* The output route contains dummy PIPs. They are ignored by gowin_pack, but it may be worth removing them.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
Added support for the INS_LOC instruction in the constraints file
(.CST), which is used to specify object placement.
Expanded treatment of IO_LOC/IO_PORT constraints, which now can
be applied to both ports and IO buffers.
Port constraints have priority.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
