From 828ec3a6188c74bd43825c11b71cc3bbbd65b26e Mon Sep 17 00:00:00 2001 From: gatecat Date: Mon, 10 May 2021 11:14:20 +0100 Subject: docs: Add a diagram showing legal/illegal site pip usage Signed-off-by: gatecat --- docs/device_resources.md | 8 ++- docs/site_pip_usage.svg | 178 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+), 1 deletion(-) create mode 100644 docs/site_pip_usage.svg diff --git a/docs/device_resources.md b/docs/device_resources.md index 323e177..9793098 100644 --- a/docs/device_resources.md +++ b/docs/device_resources.md @@ -242,6 +242,10 @@ entered via the site port corresponding to the site pin. The first site wire in the site will be the site wire attached to the output BEL pin of the site port. From there site routing continues per above. +![Wire and nodes](https://symbiflow.readthedocs.io/projects/arch-defs/en/latest/_images/rrgraph-wire.svg) + +### Use of site PIPs + It is important to note that site PIPs can only be used to access placed cells inside that site. Site PIPs cannot be used as general route-thrus, to route from site input to output. General route-thrus across entire sites should use @@ -255,7 +259,9 @@ an associated flipflop input inside the site. The tile PIP would be used to route across the entire site as part of the general, inter-tile, routing problem. -![Wire and nodes](https://symbiflow.readthedocs.io/projects/arch-defs/en/latest/_images/rrgraph-wire.svg) +A diagram illustrating the legal and illegal uses is shown below. + +![Site PIP usage](site_pip_usage.svg) ### Tile Types and site types diff --git a/docs/site_pip_usage.svg b/docs/site_pip_usage.svg new file mode 100644 index 0000000..ebf5721 --- /dev/null +++ b/docs/site_pip_usage.svg @@ -0,0 +1,178 @@ + + + + + + + + + + + + + + + + + + + + LUT6 + + + LUT5 + + + + + + + + + + + + + + + + DFF + + + + + + + + + + + + + + + + + + + + + + + + + + + + + LUT6 + + + LUT5 + + + + + + + + + + + + + + + + DFF + + + + + + + + + + + + + + + + + + + + + + + + + + + + + LUT6 + + + LUT5 + + + + + + + + + + + + + + + + DFF + + + + + + + + + + + + + + + + + + + + + Legal - site routing + used to access DFF + input and output + + + Illegal - not being + used to access bound + bel inside site; tile PIP + should be used instead + + + + + Illegal - red dashed + part not being used to + access bound bel inside + site; tile PIP should be used + instead for that part + + + + + -- cgit v1.2.3