* Gowin. Add the ability to place registers in IOB
IO blocks have registers: for input, for output and for OutputEnable
signal - IREG, OREG and TREG respectively.
Each of the registers has one implicit non-switched wire, which one
depends on the type of register (IREG has a Q wire, OREG has a D wire).
Although the registers can be activated independently of each other they
share the CLK, ClockEnable and LocalSetReset wires and this places
restrictions on the possible combinations of register types in a single
IO.
Register placement in IO blocks is enabled by specifying the command
line keys --vopt ireg_in_iob, --vopt oreg_in_iob, or --vopt ioreg_in_iob.
It should be noted that specifying these keys leads to attempts to place
registers in IO blocks, but no errors are generated in case of failure.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. Registers in IO
Check for unconnected ports.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. IO regs. Verbose warnings.
If an attempt to place an FF in an IO block fails, issue a warning
detailing the reason for the failure, whether it is a register type
conflict, a network requirement violation, or a control signal conflict.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. BUGFIX. Fix FFs compatibility.
Flipflops with a fixed ClockEnable input cannot coexist with flipflops
with a variable one.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. FFs in IO. Changing diagnostic messages.
Placement modes are still specified by the command line keys
ireg_in_iob/oreg_in_iob/ioreg_in_iob, but also introduces more granular
control in the form of attributes at I/O ports:
(* NOIOBFF *) - registers are never placed in this IO,
(* IOBFF *) - registers must be placed in this IO, in case of failure
a warning (not an error) with the reason for nonplacement is issued,
_attribute_absence_ - no diagnostics will be issued: managed to place - good, failed - not bad either.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. Registers in IO.
Change the logic for handling command line keys and attributes -
attributes allow routines to be placed in IO regardless of global mode.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* Gowin. Registers in IO. Fix style.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
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Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
c565e364bc