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| author | kittennbfive <58293822+kittennbfive@users.noreply.github.com> | 2020-09-28 14:49:35 +0000 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-09-28 14:49:35 +0000 |
| commit | b2438caec36bcd35606f16e52d28b011bba4d26b (patch) | |
| tree | 33ad01f1a8bcbc94fad2e36d6d28e0eed460b7e9 /docs | |
| parent | 9aff6aa55c212df448477f3e28711ac3d0ee5aff (diff) | |
| download | nextpnr-b2438caec36bcd35606f16e52d28b011bba4d26b.tar.gz nextpnr-b2438caec36bcd35606f16e52d28b011bba4d26b.tar.bz2 nextpnr-b2438caec36bcd35606f16e52d28b011bba4d26b.zip | |
update doc - UNTESTED on real hardware
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/constraints.md | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/docs/constraints.md b/docs/constraints.md index 67c8ddd7..4917b33f 100644 --- a/docs/constraints.md +++ b/docs/constraints.md @@ -9,11 +9,18 @@ The iCE40 architecture supports PCF constraints thus: set_io led[0] 3 -and the ECP5 architecture supports a subset of LPF constraints: +and the ECP5 architecture supports a subset of LPF constraints (for details see Lattice Technical Note "FPGA-TN-02032 1.3"): LOCATE COMP "led[0]" SITE "E16"; IOBUF PORT "led[0]" IO_TYPE=LVCMOS25; - + IOBUF ... DRIVE=8; + IOBUF ... OPENDRAIN=ON|OFF; + IOBUF ... TERMINATION=50; + IOBUF ... DIFFRESISTOR=100; //for differential IO only + IOBUF ... CLAMP=ON|OFF; + IOBUF ... PULLMODE=UP|DOWN|NONE; + IOBUF ... SLEWRATE=FAST|SLOW; //outputs only + IOBUF ... HYSTERESIS=ON|OFF; ## Absolute Placement Constraints |