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Add more SKY130 cell libraries.
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Also increase the documentation about skywater process.

Signed-off-by: Tim 'mithro' Ansell <[email protected]>
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@mithro
mithro committed Sep 5, 2023
1 parent 8674fb5 commit da6d67f
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168 changes: 168 additions & 0 deletions vlsiffra/tech/sky130.py
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from amaranth import Elaboratable, Instance

"""
Skywater's 130nm process technology with Google open source PDK found at
https://github.com/google/skywater-pdk and https://skywater-pdk.readthedocs.io
The process technology offers `multiple standard cell libraries <libraries>`_
with different trade offs. The `Standard Cells Library Index Spreadsheet
<stdindex>`_ is useful to understand what cells exist in which libraries.
.. _libraries: https://skywater-pdk.readthedocs.io/en/main/contents/libraries/foundry-provided.html
.. _stdindex: https://docs.google.com/spreadsheets/d/1KMZ215M_7YQb0l-vCyVdzSsRzaSJN4VVGsTwf4wFK3k/edit#gid=139199577
"""


class SKY130Process(Elaboratable):
LIBRARY = None

def _PoweredInstance(self, *args, **kwargs):
if self._powered:
kwargs.update({
"i_VPWR": self.VPWR,
"i_VPB": self.VPWR,
"i_VGND": self.VGND,
"i_VNB": self.VGND
})
return Instance(*args, **kwargs)

def _generate_and(self, a, b, o):
andgate = self._PoweredInstance(
self.LIBRARY + "__and2_1",
i_A=a,
i_B=b,
o_X=o
)

self.m.submodules += andgate

def _generate_xor(self, a, b, o):
xorgate = self._PoweredInstance(
self.LIBRARY + "__xor2_1",
i_A=a,
i_B=b,
o_X=o
)

self.m.submodules += xorgate

def _generate_inv(self, a, o):
invgate = self._PoweredInstance(
self.LIBRARY + "__inv_1",
i_A=a,
o_Y=o
)

self.m.submodules += invgate

def _generate_full_adder(self, a, b, carry_in, sum_out, carry_out, name=None):
fa = self._PoweredInstance(
self.LIBRARY + "__fa_1",
o_COUT=carry_out,
o_SUM=sum_out,
i_A=a,
i_B=b,
i_CIN=carry_in
)
if name:
self.m.submodules[name] = fa
else:
self.m.submodules += fa

def _generate_half_adder(self, a, b, sum_out, carry_out, name=None):
ha = self._PoweredInstance(
self.LIBRARY + "__ha_1",
o_COUT=carry_out,
o_SUM=sum_out,
i_A=a,
i_B=b
)

if name:
self.m.submodules[name] = ha
else:
self.m.submodules += ha

# Used in adder
def _generate_ao21(self, a1, a2, b1, o):
# 2-input AND into first input of 2-input OR
a21o = self._PoweredInstance(
self.LIBRARY + "__a21o_1",
o_X=o,
i_A1=a1,
i_A2=a2,
i_B1=b1
)

self.m.submodules += a21o

# Used in multiplier
def _generate_ao22(self, a1, a2, b1, b2, o):
# 2-input AND into both inputs of 2-input OR
a22ogate = self._PoweredInstance(
self.LIBRARY + "__a22o_1",
i_A1=a1,
i_A2=a2,
i_B1=b1,
i_B2=b2,
o_X=o
)

self.m.submodules += a22ogate

# Used in multiplier
def _generate_ao32(self, a1, a2, a3, b1, b2, o):
# 3-input AND into first input, and 2-input AND into 2nd input of 2-input OR
a32ogate = self._PoweredInstance(
self.LIBRARY + "__a32o_1",
i_A1=a1,
i_A2=a2,
i_A3=a3,
i_B1=b1,
i_B2=b2,
o_X=o
)

self.m.submodules += a32ogate


class SKY130HSProcess(SKY130Process):
""" SKY130 process technology with high speed standard cells.
Libraries sky130_fd_sc_hs (high speed), sky130_fd_sc_ms (medium speed),
sky130_fd_sc_ls (low speed), and sky130_fd_sc_lp (low power) are compatible
in size, with a 0.48 x 3.33um site, equivalent to about 11 met1 tracks.
The medium and low speed can be swapped in after place and route to reduce
power consumption.
"""

LIBRARY = "sky130_fd_sc_hs"


class SKY130HDProcess(SKY130Process):
""" SKY130 process technology with high density standard cells.
Libraries sky130_fd_sc_hd (high density) and sky130_fd_sc_hdll (high
density, low leakage) contain standard cells that are smaller, utilizing a
0.46 x 2.72um site, equivalent to 9 met1 tracks.
"""

LIBRARY = "sky130_fd_sc_hd"


class SKY130HVLProcess(SKY130Process):
""" SKY130 process technology with high voltage standard cells.
The sky130_fd_sc_hvl (high voltage) library contains 5V devices and
utilizes a 0.48 x 4.07um site, or 14 met1 tracks.
The high voltage library is missing a number of standard cells,
* a211o
* a211oi
* a21bo
* xnor3
* xor3
"""

LIBRARY = "sky130_fd_sc_hvl"
114 changes: 2 additions & 112 deletions vlsiffra/tech/sky130hd.py
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from amaranth import Elaboratable, Instance


class SKY130HDProcess(Elaboratable):
def _PoweredInstance(self, *args, **kwargs):
if self._powered:
kwargs.update({
"i_VPWR": self.VPWR,
"i_VPB": self.VPWR,
"i_VGND": self.VGND,
"i_VNB": self.VGND
})
return Instance(*args, **kwargs)

def _generate_and(self, a, b, o):
andgate = self._PoweredInstance(
"sky130_fd_sc_hd__and2_1",
i_A=a,
i_B=b,
o_X=o
)

self.m.submodules += andgate

def _generate_xor(self, a, b, o):
xorgate = self._PoweredInstance(
"sky130_fd_sc_hd__xor2_1",
i_A=a,
i_B=b,
o_X=o
)

self.m.submodules += xorgate

def _generate_inv(self, a, o):
invgate = self._PoweredInstance(
"sky130_fd_sc_hd__inv_1",
i_A=a,
o_Y=o
)

self.m.submodules += invgate

def _generate_full_adder(self, a, b, carry_in, sum_out, carry_out, name=None):
fa = self._PoweredInstance(
"sky130_fd_sc_hd__fa_1",
o_COUT=carry_out,
o_SUM=sum_out,
i_A=a,
i_B=b,
i_CIN=carry_in
)
if name:
self.m.submodules[name] = fa
else:
self.m.submodules += fa

def _generate_half_adder(self, a, b, sum_out, carry_out, name=None):
ha = self._PoweredInstance(
"sky130_fd_sc_hd__ha_1",
o_COUT=carry_out,
o_SUM=sum_out,
i_A=a,
i_B=b
)

if name:
self.m.submodules[name] = ha
else:
self.m.submodules += ha

# Used in adder
def _generate_ao21(self, a1, a2, b1, o):
""" 2-input AND into first input of 2-input OR. """
a21o = self._PoweredInstance(
"sky130_fd_sc_hd__a21o_1",
o_X=o,
i_A1=a1,
i_A2=a2,
i_B1=b1
)

self.m.submodules += a21o

# Used in multiplier
def _generate_ao22(self, a1, a2, b1, b2, o):
""" 2-input AND into both inputs of 2-input OR. """
a22ogate = self._PoweredInstance(
"sky130_fd_sc_hd__a22o_1",
i_A1=a1,
i_A2=a2,
i_B1=b1,
i_B2=b2,
o_X=o
)

self.m.submodules += a22ogate

# Used in multiplier
def _generate_ao32(self, a1, a2, a3, b1, b2, o):
""" 3-input AND into first input, and 2-input AND into 2nd input of 2-input OR. """
a32ogate = self._PoweredInstance(
"sky130_fd_sc_hd__a32o_1",
i_A1=a1,
i_A2=a2,
i_A3=a3,
i_B1=b1,
i_B2=b2,
o_X=o
)

self.m.submodules += a32ogate
# Backwards compatibility name.
from .sky130 import SKY130HDProcess # noqa: F401

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