S2R(1)

📦 version 5.1.1-unstable-2025-02, in nixos 26.05, nixpkgs unstable

💅 S2R(1) — like, the symbolic-to-real glow-up page

okay so this is s2r, bestie, and it lives in the ALLIANCE USER COMMANDS section of the manual. Buckle up, we're going from symbolic to physical and it's gonna be iconic ✨

🌸 NAME

s2r — does the process mapping from symbolic layout to physical layout. that's the whole vibe. 💫

🎀 SYNOPSIS

s2r [-tc1rv] source [result]

🦋 ORIGIN

so this software? it belongs to the ALLIANCE CAD SYSTEM, developed by the ASIM team at the LIP6 laboratory of Université Pierre et Marie CURIE, in Paris, France. 🇫🇷 periodt.

✨ DESCRIPTION

the goal of s2r is literally to perform the translation from the symbolic layout to physical layout for the foundry. no cap. 🔥

s2r uses a technology file whose name is defined by the environment variable RDS_TECHNO_NAME.

some cells, like I/O pads, are specific to a given foundry. in the symbolic methodology, these cells are phantom cells — meaning only their abutment box and connectors are present. s2r will substitute physical cells to the symbolic phantom cells. 👻➡️💖

beware, bestie: this implies that the manufacturer cells must be modified by hand to ensure the abutment box is a symbolic grid step multiple, and that the real connectors are centered on symbolic grid. yes, by hand. we don't make the rules. 😭

in order for the replacement to work well, the physical cells must have the abutment box lower left corner at coordinate (0,0). the name of cells to be replaced are written in the catalog file with the G attribute — see catal(5) for details on that file. see also ring(1) for more on pads. 🫶

output can be generated in either cif or gds formats, to fit the manufacturer requirements. slay. 💅

🌈 who is this even for

mainly two kinds of users are concerned with s2r:

  • experts — they should be able to parametrize the technology file for a new process; the technology file is described in techno(5).
  • designers — they are not directly concerned with the target process, but need to be able to compute real capacitances for simulation. that's the whole point, honestly.

🍓 the arguments

the source argument is the name of the symbolic layout file to be translated.

the optional result argument indicates the name to be given to the real layout output. this name is also the name of the top level model of the layout hierarchy. if result name is omitted, then source name is used. easy. 🎀

🧚 the six environment variables

six environment variables must be set for proper usage of s2r, all of them having default values, thus ensuring the possibility of using it "as it is". iconic behaviour honestly. ✨

  • MBK_IN_PH — the input format for symbolic layout is given by this environment variable. the possible values are cp, ap. default is cp. see MBK_IN_PH(1) for details.
  • MBK_CATA_LIB — sets the directories that are to be searched thru for reading files. the searching mechanism first look in MBK_WORK_LIB(1); MBK_WORK_LIB defines the path where the generated file is saved. make sure the write permissions are set up correctly, otherwise no save will occur. 👀 (like, actually check them, bestie.)
  • MBK_CATAL_NAME — this indicates the name of the catalog file used for pad substitution. for the appropriate syntax of this file, see catal(5).
  • RDS_IN — defines the format to be used as input for cell substitution. the available ones are cif and gds (default one). the cells to be parsed must not contain 45 degrees wires. if an unknown layer is encountered, the entire cell will be skipped. 💀 brutal but true.
  • RDS_OUT — gives the format of the output file. this may be either cif or gds (default is gds).
  • RDS_TECHNO_NAME — this points to the technology file to be used for symbolic to real translation. this file is in general shared between all the designers. it is the full path name to the file location, with the extension. 🌟

👑 OPTIONS

without option, s2r should produce a layout that fits for the foundry. nevertheless, its behaviour can be modified when invoked with the following options:

  • -t — suppress the denotching phase. s2r performs gap filling, denotching in order to avoid DRC errors. this operation is time consuming. it is mandatory for the foundry but not really useful for capacitance evaluation. ⏳
  • -c — deletes connectors and node names at all hierarchy level. these objects link the physical view and the logical view of a chip. if simulation is to be done after physical mapping, connectors must appear, so that the extractors and simulators can use them. this must not be used when preparing a final layout for the foundry. for the factory, the top level connectors are forbidden, since they do not represent any physical reality. 🙈
  • -1 — creates the top level cell with the instances as black boxes. this may be useful for hierarchical extractors, since the file size may be greatly reduced. 📉
  • -r — does not replace black boxes. cells flagged with the G attribute in the catal(5) file will not be replaced by their equivalent layout loaded from disk. 🚫
  • -v — verbose mode on. the girlies love a chatty terminal. 🗣️

🫶 EXAMPLES

you should first have a correct execution environment. it is recommended to put it in the ".cshrc" file if in c shell, as in the example below:

setenv MBK_IN_PH              ap
setenv MBK_WORK_LIB      ~fred/mbk/layout
setenv MBK_CATA_LIB      ~franck/s2r:/alliance/cells
setenv MBK_CATAL_NAME    catalog
setenv RDS_TECHNO_NAME   /labo/etc/prol15.rds
setenv RDS_IN            gds
setenv RDS_OUT           gds
s2r -c na2_y

this invocation will produce the cell na2_y from the standard cell library in real layout, without connectors, scotches if needed, in gds format. chef's kiss. 🧑‍🍳💋

💜 SEE ALSO

mbk(1), ring(1), MBK_IN_PH(1), MBK_CATA_LIB(1), MBK_WORK_LIB(1), MBK_CATAL_NAME(1), RDS_IN(1), RDS_OUT(1), RDS_TECHNO_NAME(1), techno(5), catal(5).

go read them, i'll wait. 📚

🌸 DIAGNOSTICS

the actual version of the gds parser and driver doesn't translate neither connectors, nor node names. if an extraction on s2r output is needed, cif format will create the connectors using cif extension 4X, and the node names with 4N. noted and filed away. 🗂️

⭐ BUG REPORT

this tool is under development at the ASIM department of the LIP6 laboratory.

we need your feedback to improve documentation and tools. fr fr, tell them. 📬

and that's the page, bestie!! written by the lovely people at ASIM/LIP6 back on October 1, 1997 — yes, she's vintage, and she's still serving 💅✨🎀

📦 where this page comes from