Saturday, 2018-05-26

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mithrokem_: Thanks -- will test out the pass_gate stuff again soon02:54
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mithrodaveshah: If you happen to be around, I have some questions about ice40 routing fabric and wanted to know if you thought this looked valid or not....16:12
tpbTitle: Investigate weird routing in ice40 arch · Issue #131 · SymbiFlow/symbiflow-arch-defs · GitHub (at
daveshahmithro: have limited time this evening to look at stuff16:15
daveshahBut at a glance it seems dodgy to me16:15
daveshahWhat is being connected to on the second image?16:15
daveshahThis could only happen using neighbour links, as far as I know, and there is no direct connection between them and the span12s16:17
mithrodaveshah: Yeah seems a bit weird, I'm going to write another icebox tool because I just can't get the info I need from the current docs16:33
daveshahmithro: is quite nice because it shows the net number, but does not show all span <-> logic/local connectivity16:51
tpbTitle: ICE40 layout viewer (at
tpbTitle: Snippet | IRCCloud (at
daveshahmithro: neat!17:07
mithrodaveshah: I just need to work out how to get the permanent connections now...17:08
daveshahmithro: look at and
tpbTitle: icestorm/ at tiny_ice40 · daveshah1/icestorm · GitHub (at
daveshahthat's how they are output into the chipdb17:09
daveshahbeware that they will vary depending on location17:09
daveshahdue to the edges and corners of the device being different with IO etc17:10
mithrodaveshah: I started with icebox_maps.py17:13
benreynwarIf I run "make wire.patched.disp ARCH=testarch" in symbiflow-test-archs, I get an error "TypeError: Pin doesn't have port_name BLK_IG-IBUF(0)->None[None]".17:19
benreynwarIs there a branch of vpr I should be using that outputs port names in the rr_graph xml?17:20
mithrobenreynwar: Yes - upstream master does17:20
mithrobenreynwar: you might want to take a look at my 4mcmaster branch17:21
mithrobenreynwar: I need to clean it up a bit17:21
benreynwarmithro: Will do.  Thanks.17:21
mithrobenreynwar: But I did a major refactor of the tests17:22
mithrobenreynwar: I have a weekend project for you if you want to learn more about building rr_graphs :-P17:22
benreynwarYou're welcome to point me in a specific direction, but I'm sneaking in bits of work between entertaining kids so I can't guarantee much progress :p.17:24
mithrobenreynwar: I need a tool which checks that you can get from every SOURCE to every SINK17:40
mithrobenreynwar: It should be a pretty easy graph traversal problem...17:44
mithrodaveshah: Do you know if there is an easy way to map between pin numbers and io_tile coordinates?17:45
daveshahmithro: No, you have to use the mapping in icebox17:45
mithrodaveshah: btw - what are .sym values in an .asc file?17:46
mithrodaveshah: They seem to be names for things - but I don't get the numbers?17:46
daveshahThey map net names to icebox net numbers17:46
daveshahFor diagnostics in icetime etc17:47
mithrodaveshah: In what structure do I look up the numbers?17:48
daveshahmithro: they are the net numbers in the chipdb. Don't know more than that and not at computer so can't give any further info17:49
daveshahHave a look at how they end up in the chipdb17:49
mithrodaveshah: Thanks, the icebox_chipdb is what I needed to look at17:51
benreynwarmithro: Sounds like a nice little project for me.18:33
benreynwarmithro: Implemented it with method on the RoutingGraph object.  No test yet, so likely buggy.21:13
tpbTitle: Add methods to RoutingGraph to determine whether any sink nodes are i… by benreynwar · Pull Request #132 · SymbiFlow/symbiflow-arch-defs · GitHub (at
mithrobenreynwar: I'd love to see some tests :-P21:15
mithrobenreynwar: I'm not smart enough to write this type of function without writing tests :-P21:18
benreynwarYep.  Hence the comment not to merge it yet :).21:20
mithrobenreynwar: If you put a WIP in the title of the pull request then the WIP check will prevent me accidently merging it :-P21:21
mithrobe back in an 30 minutes, going to find some caffeine and go for a walk...21:23
benreynwarI'm disassembling and recovering a couch now, but will probably get on my laptop again later today.21:27
mithroI need to go buy a couch...21:58
mithrokem_: Hopefully you are not around, but on the of chance you are -- have you used IO pad placement recently?22:09
tpbTitle: Snippet | IRCCloud (at
tpbTitle: Snippet | IRCCloud (at
mithrodaveshah / jhol: Just place-and-routed the iceblink example with real pin locs!22:26

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