synth_nexus - synthesis for Lattice Nexus FPGAs¶
yosys> help synth_nexus
¶
synth_nexus [options]
This command runs synthesis for Lattice Nexus FPGAs.
-top <module>
use the specified module as top module
-family <device>
run synthesis for the specified Nexus device
supported values: lifcl, lfd2nx
-json <file>
write the design to the specified JSON file. writing of an output file
is omitted if this parameter is not specified.
-vm <file>
write the design to the specified structural Verilog file. writing of
an output file is omitted if this parameter is not specified.
-run <from_label>:<to_label>
only run the commands between the labels (see below). an empty
from label is synonymous to 'begin', and empty to label is
synonymous to the end of the command list.
-noflatten
do not flatten design before synthesis
-dff
run 'abc'/'abc9' with -dff option
-retime
run 'abc' with '-dff -D 1' options
-noccu2
do not use CCU2 cells in output netlist
-nodffe
do not use flipflops with CE in output netlist
-nolram
do not use large RAM cells in output netlist
note that large RAM must be explicitly requested with a (* lram *)
attribute on the memory.
-nobram
do not use block RAM cells in output netlist
-nolutram
do not use LUT RAM cells in output netlist
-nowidelut
do not use PFU muxes to implement LUTs larger than LUT4s
-noiopad
do not insert IO buffers
-nodsp
do not infer DSP multipliers
-abc9
use new ABC9 flow (EXPERIMENTAL)
The following commands are executed by this synthesis command:
begin:
read_verilog -lib -specify +/nexus/cells_sim.v +/nexus/cells_xtra.v
hierarchy -check -top <top>
coarse:
proc
flatten
tribuf -logic
deminout
opt_expr
opt_clean
check
opt -nodffe -nosdff
fsm
opt
wreduce
peepopt
opt_clean
share
techmap -map +/cmp2lut.v -D LUT_WIDTH=4
opt_expr
opt_clean
techmap -map +/mul2dsp.v [...] (unless -nodsp)
techmap -map +/nexus/dsp_map.v (unless -nodsp)
alumacc
opt
memory -nomap
opt_clean
map_ram:
memory_libmap -lib +/nexus/lutrams.txt -lib +/nexus/brams.txt -lib +/nexus/lrams.txt -no-auto-huge [-no-auto-block] [-no-auto-distributed] (-no-auto-block if -nobram, -no-auto-distributed if -nolutram)
techmap -map +/nexus/lutrams_map.v -map +/nexus/brams_map.v -map +/nexus/lrams_map.v
map_ffram:
opt -fast -mux_undef -undriven -fine
memory_map
opt -undriven -fine
map_gates:
techmap -map +/techmap.v -map +/nexus/arith_map.v
iopadmap -bits -outpad OB I:O -inpad IB O:I -toutpad OBZ ~T:I:O -tinoutpad BB ~T:O:I:B A:top (skip if '-noiopad')
opt -fast
abc -dff -D 1 (only if -retime)
map_ffs:
opt_clean
dfflegalize -cell $_DFF_P_ 01 -cell $_DFF_PP?_ r -cell $_SDFF_PP?_ r -cell $_DLATCH_?_ x [-cell $_DFFE_PP_ 01 -cell $_DFFE_PP?P_ r -cell $_SDFFE_PP?P_ r] ($_*DFFE_* only if not -nodffe)
zinit -all w:* t:$_DFF_?_ t:$_DFFE_??_ t:$_SDFF* (only if -abc9 and -dff
techmap -D NO_LUT -map +/nexus/cells_map.v
opt_expr -undriven -mux_undef
simplemap
attrmvcp -copy -attr syn_useioff
opt_clean
map_luts:
techmap -map +/nexus/latches_map.v
abc -dress -lut 4:5
clean
map_cells:
techmap -map +/nexus/cells_map.v
setundef -zero
hilomap -singleton -hicell VHI Z -locell VLO Z
clean
check:
autoname
hierarchy -check
stat
check -noinit
blackbox =A:whitebox
json:
write_json <file-name>
vm:
write_verilog <file-name>