doitcode/sram.py

# SPDX-License-Identifier: GPL-2.0-or-later
from pdkmaster.design import circuit as _ckt, library as _lbry

from c4m.pdk import sky130

from . import frame as _frm


__all__ = ["ConnectedSRAM"]


class _io_spec:
    def __init__(self, *, io_number: int, sram_signal: str):
        self.io_number = io_number
        self.sram_signal = sram_signal


io_specs = (
    _io_spec(sram_signal="a[8]", io_number=14),
    _io_spec(sram_signal="a[7]", io_number=15),
    _io_spec(sram_signal="a[6]", io_number=16),
    _io_spec(sram_signal="a[5]", io_number=17),
    _io_spec(sram_signal="a[4]", io_number=18),
    _io_spec(sram_signal="a[3]", io_number=19),
    _io_spec(sram_signal="a[2]", io_number=20),
    _io_spec(sram_signal="a[1]", io_number=21),
    _io_spec(sram_signal="a[0]", io_number=22),
)
io_sig2spec = {
    spec.sram_signal: spec
    for spec in io_specs
}

class ConnectedSRAM(_lbry._OnDemandCell[_lbry.Library]):
    def __init__(self, *, lib: _lbry.Library):
        super().__init__(lib=lib, name="ConnectedSRAM")

    def _create_circuit(self):
        stdcells = sky130.stdcelllib.cells

        mem_factory = sky130.Sky130SP6TFactory(lib=self.lib)

        sram_cell = mem_factory.block(words=512, word_size=8, we_size=1)
        
        ckt = self.new_circuit()

        ckt.instantiate(sram_cell, name="sram")

    def _create_layout(self):
        ckt = self.circuit
        nets = ckt.nets
        insts = ckt.instances

        layouter = self.new_circuitlayouter()
        layout = layouter.layout

        _sram_lay = layouter.inst_layout(inst=insts.sram)
        _sram_bb = _sram_lay.boundary
        assert _sram_bb is not None

        o = sky130.tech.on_grid(_frm.boundary.center - _sram_bb.center)
        layouter.place(_sram_lay, origin=o)

        layout.boundary = _frm.boundary