mirror of https://github.com/VLSIDA/OpenRAM.git
590 lines
32 KiB
Python
590 lines
32 KiB
Python
import design
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import debug
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from tech import drc, parameter, spice
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from vector import vector
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import contact
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from math import ceil
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from ptx import ptx
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from globals import OPTS
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class pbitcell(design.design):
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"""
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This module implements a parametrically sized multi-port bitcell
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"""
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def __init__(self, num_write=1, num_read=1):
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name = "pbitcell"
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design.design.__init__(self, name)
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debug.info(2, "create a multi-port bitcell with {0} write ports and {1} read ports".format(num_write, num_read))
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self.num_write = num_write
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self.num_read = num_read
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self.create_layout()
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self.DRC_LVS()
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def add_pins(self):
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for k in range(0,self.num_write):
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self.add_pin("WROW{}".format(k))
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for k in range(0,self.num_write):
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self.add_pin("WBL{}".format(k))
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self.add_pin("WBL_bar{}".format(k))
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for k in range(0,self.num_read):
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self.add_pin("RROW{}".format(k))
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for k in range(0,self.num_read):
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self.add_pin("RBL{}".format(k))
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self.add_pin("RBL_bar{}".format(k))
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self.add_pin("vdd")
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self.add_pin("gnd")
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def create_layout(self):
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self.create_ptx()
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self.add_storage()
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self.add_rails()
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if(self.num_write > 0):
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self.add_write_transistors()
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if(self.num_read > 0):
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self.add_read_transistors()
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self.extend_well()
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#self.add_fail()
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def create_ptx(self):
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""" Create ptx for all transistors. Also define measurements to be used throughout bitcell """
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# create ptx for inverter transistors
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self.i_nmos = ptx(width=2*parameter["min_tx_size"],
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tx_type="nmos",
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connect_active=True,
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connect_poly=True)
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self.add_mod(self.i_nmos)
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self.i_pmos = ptx(width=parameter["min_tx_size"],
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tx_type="pmos",
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connect_active=True,
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connect_poly=True)
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self.add_mod(self.i_pmos)
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# create ptx for write transitors
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self.w_nmos = ptx(width=parameter["min_tx_size"],
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tx_type="nmos",
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connect_active=True,
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connect_poly=True)
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self.add_mod(self.w_nmos)
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# create ptx for read transistors
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self.r_nmos = ptx(width=2*parameter["min_tx_size"],
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mults=2,
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tx_type="nmos",
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connect_active=False,
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connect_poly=False)
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self.add_mod(self.r_nmos)
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# determine metal contact extensions
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self.ip_ex = 0.5*(self.i_pmos.active_contact.height - self.i_pmos.active_height)
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self.w_ex = 0.5*(self.w_nmos.active_contact.height - self.w_nmos.active_height)
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# determine global measurements
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w_spacer = drc["minwidth_metal2"] + self.w_ex + contact.poly.width + drc["poly_to_field_poly"] + drc["poly_extend_active"]
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r_spacer = 2*drc["minwidth_poly"] + drc["minwidth_metal1"] + 2*contact.poly.width
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rw_spacer = drc["minwidth_poly"] + drc["poly_to_field_poly"] + drc["minwidth_metal2"] + 2*contact.poly.width + self.w_ex
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self.w_tile_width = w_spacer + self.w_nmos.active_height
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self.r_tile_width = r_spacer + self.r_nmos.active_height
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self.inv_gap = drc["poly_to_active"] + drc["poly_to_field_poly"] + 2*contact.poly.width + drc["minwidth_metal1"] + self.ip_ex
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self.cross_heightL = self.i_nmos.active_height + drc["poly_to_active"] + 0.5*contact.poly.width
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self.cross_heightU = self.i_nmos.active_height + drc["poly_to_active"] + drc["poly_to_field_poly"] + 1.5*contact.poly.width
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self.leftmost_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"]) \
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- self.num_write*(w_spacer + self.w_nmos.active_height) \
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- rw_spacer - self.r_nmos.active_height - (self.num_read-1)*self.r_tile_width \
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- 3*drc["minwidth_metal1"]
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self.botmost_ypos = -2*drc["minwidth_metal1"] - self.num_write*2*drc["minwidth_metal2"] - self.num_read*2*drc["minwidth_metal2"]
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self.topmost_ypos = self.inv_gap + self.i_nmos.active_height + self.i_pmos.active_height + drc["poly_extend_active"] + 2*drc["minwidth_metal1"]
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self.cell_width = -2*self.leftmost_xpos
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self.cell_height = self.topmost_ypos - self.botmost_ypos
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def add_storage(self):
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"""
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Creates the crossed coupled inverters that act as storage for the bitcell.
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"""
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lit_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"])
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rit_xpos = 1.5*parameter["min_tx_size"]
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it_ypos = self.inv_gap + self.i_nmos.active_height
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# create active
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self.i_nmosL = self.add_inst(name="i_nmosL",
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mod=self.i_nmos,
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offset=[lit_xpos,0])
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self.connect_inst(["Q_bar", "Q", "gnd", "gnd"])
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self.i_nmosR = self.add_inst(name="i_nmosR",
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mod=self.i_nmos,
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offset=[rit_xpos,0])
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self.connect_inst(["gnd", "Q_bar", "Q", "gnd"])
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self.i_pmosL = self.add_inst(name="i_pmosL",
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mod=self.i_pmos,
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offset=[lit_xpos, it_ypos])
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self.connect_inst(["Q_bar", "Q", "vdd", "vdd"])
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self.i_pmosR = self.add_inst(name="i_pmosR",
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mod=self.i_pmos,
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offset=[rit_xpos, it_ypos])
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self.connect_inst(["vdd", "Q_bar", "Q", "vdd"])
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# connect poly for inverters
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self.add_path("poly", [self.i_nmosL.get_pin("G").uc(), self.i_pmosL.get_pin("G").bc()])
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self.add_path("poly", [self.i_nmosR.get_pin("G").uc(), self.i_pmosR.get_pin("G").bc()])
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# connect drains for inverters
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self.add_path("metal1", [self.i_nmosL.get_pin("D").uc(), self.i_pmosL.get_pin("D").bc()])
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self.add_path("metal1", [self.i_nmosR.get_pin("S").uc(), self.i_pmosR.get_pin("S").bc()])
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# add contacts to connect gate poly to drain/source metal1 (to connect Q to Q_bar)
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offsetL = vector(self.i_nmosL.get_pin("G").rc().x + drc["poly_to_field_poly"] + 0.5*contact.poly.width, self.cross_heightU)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetL,
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rotate=90)
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offsetR = vector(self.i_nmosR.get_pin("G").lc().x - drc["poly_to_field_poly"] - 0.5*contact.poly.width, self.cross_heightL)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetR,
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rotate=90)
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# connect contacts to gate poly (cross couple)
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gate_offsetR = vector(self.i_nmosR.get_pin("G").lc().x, offsetL.y)
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self.add_path("poly", [offsetL, gate_offsetR])
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gate_offsetL = vector(self.i_nmosL.get_pin("G").rc().x, offsetR.y)
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self.add_path("poly", [offsetR, gate_offsetL])
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def add_rails(self):
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""" Add rails for vdd and gnd """
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self.gnd_position = vector(self.leftmost_xpos, -2*drc["minwidth_metal1"])
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self.gnd = self.add_layout_pin(text="gnd",
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layer="metal1",
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offset=self.gnd_position,
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width=self.cell_width,
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height=drc["minwidth_metal1"])
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self.vdd_position = vector(self.leftmost_xpos, self.i_pmosL.get_pin("S").uc().y + drc["minwidth_metal1"])
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self.vdd = self.add_layout_pin(text="vdd",
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layer="metal1",
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offset=self.vdd_position,
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width=self.cell_width,
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height=drc["minwidth_metal1"])
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""" Connect inverters to rails """
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# connect nmos to gnd
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gnd_posL = vector(self.i_nmosL.get_pin("S").bc().x, self.gnd_position.y + drc["minwidth_metal1"])
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self.add_path("metal1", [self.i_nmosL.get_pin("S").bc(), gnd_posL])
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gnd_posR = vector(self.i_nmosR.get_pin("D").bc().x, self.gnd_position.y + drc["minwidth_metal1"])
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self.add_path("metal1", [self.i_nmosR.get_pin("D").bc(), gnd_posR])
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# connect pmos to vdd
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vdd_posL = vector(self.i_nmosL.get_pin("S").uc().x, self.vdd_position.y)
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self.add_path("metal1", [self.i_pmosL.get_pin("S").uc(), vdd_posL])
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vdd_posR = vector(self.i_nmosR.get_pin("D").uc().x, self.vdd_position.y)
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self.add_path("metal1", [self.i_pmosR.get_pin("D").uc(), vdd_posR])
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def add_write_transistors(self):
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""" Define variables relevant to write transistors """
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lit_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"])
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rit_xpos = 1.5*parameter["min_tx_size"] + self.i_nmos.active_width
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rot_correct = self.w_nmos.active_height
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self.w_nmosL = [None] * self.num_write
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self.w_nmosR = [None] * self.num_write
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self.wrow_positions = [None] * self.num_write
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self.wbl_positions = [None] * self.num_write
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self.wbl_bar_positions = [None] * self.num_write
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for k in range(0,self.num_write):
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""" Add transistors and WROW lines """
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# calculate transistor offsets
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w_spacer = drc["minwidth_metal2"] + self.w_ex + contact.poly.width + drc["poly_to_field_poly"] + drc["poly_extend_active"]
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wrow_ypos = self.gnd_position.y - (k+1)*2*drc["minwidth_metal2"]
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lwt_xpos = lit_xpos - (k+1)*self.w_tile_width + rot_correct
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rwt_xpos = rit_xpos + w_spacer + k*self.w_tile_width + rot_correct
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# add write transistors
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self.w_nmosL[k] = self.add_inst(name="w_nmosL{}".format(k),
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mod=self.w_nmos,
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offset=[lwt_xpos,0],
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rotate=90)
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self.connect_inst(["Q", "WROW{}".format(k), "WBL{}".format(k), "gnd"])
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self.w_nmosR[k] = self.add_inst(name="w_nmosR{}".format(k),
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mod=self.w_nmos,
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offset=[rwt_xpos,0],
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rotate=90)
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self.connect_inst(["Q_bar", "WROW{}".format(k), "WBL_bar{}".format(k), "gnd"])
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# add WROW lines
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self.wrow_positions[k] = vector(self.leftmost_xpos, wrow_ypos)
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self.add_layout_pin(text="WROW{}".format(k),
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layer="metal1",
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offset=self.wrow_positions[k],
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width=self.cell_width,
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height=drc["minwidth_metal1"])
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""" Source/WBL/WBL_bar connections """
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# add contacts to connect source of wt to WBL or WBL_bar
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offsetL = self.w_nmosL[k].get_pin("S").center()
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetL,
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rotate=90)
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offsetR = self.w_nmosR[k].get_pin("S").center()
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetR,
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rotate=90)
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# add WBL and WBL_bar (simultaneously connects to source of wt)
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self.wbl_positions[k] = vector(self.w_nmosL[k].get_pin("S").center().x - 0.5*drc["minwidth_metal2"], self.botmost_ypos)
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self.add_layout_pin(text="WBL{}".format(k),
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layer="metal2",
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offset=self.wbl_positions[k],
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width=drc["minwidth_metal2"],
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height=self.cell_height)
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self.wbl_bar_positions[k] = vector(self.w_nmosR[k].get_pin("S").center().x - 0.5*drc["minwidth_metal2"], self.botmost_ypos)
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self.add_layout_pin(text="WBL_bar{}".format(k),
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layer="metal2",
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offset=self.wbl_bar_positions[k],
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width=drc["minwidth_metal2"],
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height=self.cell_height)
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""" Gate/WROW connections """
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# add contacts to connect gate of wt to WROW (poly to metal2)
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offsetL = vector(self.w_nmosL[k].get_pin("S").lc().x - drc["minwidth_metal2"] - 0.5*contact.m1m2.width, self.w_nmosL[k].get_pin("D").bc().y - drc["minwidth_metal1"] - 0.5*contact.m1m2.height)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetL)
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetL)
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self.add_rect_center(layer="poly",
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offset=offsetL,
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width=contact.poly.width,
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height=contact.poly.height)
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offsetR = vector(self.w_nmosR[k].get_pin("S").rc().x + drc["minwidth_metal2"] + 0.5*contact.m1m2.width, self.w_nmosR[k].get_pin("D").bc().y - drc["minwidth_metal1"] - 0.5*contact.m1m2.height)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetR)
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetR)
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self.add_rect_center(layer="poly",
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offset=offsetR,
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width=contact.poly.width,
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height=contact.poly.height)
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# connect gate of wt to contact
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midL = vector(offsetL.x, self.w_nmosL[k].get_pin("G").lc().y)
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self.add_path("poly", [self.w_nmosL[k].get_pin("G").lc(), midL, offsetL])
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midR = vector(offsetR.x, self.w_nmosR[k].get_pin("G").rc().y)
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self.add_path("poly", [self.w_nmosR[k].get_pin("G").rc(), midR, offsetR])
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# add contacts to WROW lines
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offset = vector(offsetL.x, self.wrow_positions[k].y + 0.5*drc["minwidth_metal1"])
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offset,
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rotate=90)
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offset = vector(offsetR.x, self.wrow_positions[k].y + 0.5*drc["minwidth_metal1"])
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offset,
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rotate=90)
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# connect wt gate contacts to WROW contacts
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wrow_offset = vector(offsetL.x, self.wrow_positions[k].y)
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self.add_path("metal2", [offsetL, wrow_offset])
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wrow_offset = vector(offsetR.x, self.wrow_positions[k].y)
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self.add_path("metal2", [offsetR, wrow_offset])
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""" Drain/Storage connections """
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if(k == self.num_write-1):
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# add contacts to connect gate of inverters to drain of wt
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offsetL = vector(self.i_nmosL.get_pin("G").lc().x - drc["poly_to_field_poly"] - 0.5*contact.poly.width, self.cross_heightL)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetL,
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rotate=90)
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offsetR = vector(self.i_nmosR.get_pin("G").rc().x + drc["poly_to_field_poly"] + 0.5*contact.poly.width, self.cross_heightL)
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self.add_contact_center(layers=("poly", "contact", "metal1"),
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offset=offsetR,
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rotate=90)
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# connect gate of inverters to contacts
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gate_offsetL = vector(self.i_nmosL.get_pin("G").lc().x, offsetL.y)
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self.add_path("poly", [offsetL, gate_offsetL])
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gate_offsetR = vector(self.i_nmosR.get_pin("G").rc().x, offsetR.y)
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self.add_path("poly", [offsetR, gate_offsetR])
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# connect contacts to drains of wt
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midL0 = vector(self.i_nmosL.get_pin("S").lc().x - 1.5*drc["minwidth_metal1"], offsetL.y)
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midL1 = vector(self.i_nmosL.get_pin("S").lc().x - 1.5*drc["minwidth_metal1"], self.w_nmosL[k].get_pin("D").lc().y)
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self.add_path("metal1", [offsetL, midL0, midL1, self.w_nmosL[k].get_pin("D").lc()])
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midR0 = vector(self.i_nmosR.get_pin("D").rc().x + 1.5*drc["minwidth_metal1"], offsetR.y)
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midR1 = vector(self.i_nmosR.get_pin("D").rc().x + 1.5*drc["minwidth_metal1"], self.w_nmosR[k].get_pin("D").rc().y)
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self.add_path("metal1", [offsetR, midR0, midR1, self.w_nmosR[k].get_pin("D").rc()])
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def add_read_transistors(self):
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""" Define variables relevant to read transistors """
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lit_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"])
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rit_xpos = 1.5*parameter["min_tx_size"] + self.i_nmos.active_width
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lwt_xpos = lit_xpos - self.num_write*self.w_tile_width
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rwt_xpos = rit_xpos + self.num_write*self.w_tile_width
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wrow_ypos = self.gnd_position.y - self.num_write*2*drc["minwidth_metal2"]
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rot_correct = self.r_nmos.active_height
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r_spacer = 2*drc["minwidth_poly"] + drc["minwidth_metal1"] + 2*contact.poly.width
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rw_spacer = drc["minwidth_poly"] + drc["poly_to_field_poly"] + drc["minwidth_metal2"] + 2*contact.poly.width + self.w_ex
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self.r_nmosL = [None] * self.num_read
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self.r_nmosR = [None] * self.num_read
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self.rrow_positions = [None] * self.num_read
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self.rbl_positions = [None] * self.num_read
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self.rbl_bar_positions = [None] * self.num_read
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for k in range(0,self.num_read):
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""" Add transistors and RROW lines """
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# calculate transistor offsets
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lrt_xpos = lwt_xpos - rw_spacer - self.r_nmos.active_height - k*self.r_tile_width + rot_correct
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rrt_xpos = rwt_xpos + rw_spacer + k*self.r_tile_width + rot_correct
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# add read transistors
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self.r_nmosL[k] = self.add_inst(name="r_nmosL",
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mod=self.r_nmos,
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offset=[lrt_xpos,0],
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rotate=90)
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self.connect_inst(["RROW{}".format(k), "Q", "RBL{}".format(k), "gnd"])
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self.r_nmosR[k] = self.add_inst(name="r_nmosR",
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mod=self.r_nmos,
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offset=[rrt_xpos,0],
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rotate=90)
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self.connect_inst(["RROW{}".format(k), "Q_bar", "RBL_bar{}".format(k), "gnd"])
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# add RROW lines
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rrow_ypos = wrow_ypos - (k+1)*2*drc["minwidth_metal2"]
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self.rrow_positions[k] = vector(self.leftmost_xpos, rrow_ypos)
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self.add_layout_pin(text="RROW{}".format(k),
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layer="metal1",
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offset=self.rrow_positions[k],
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width=self.cell_width,
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height=drc["minwidth_metal1"])
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|
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""" Source of RA transistor / GND connection """
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offset = vector(self.r_nmosL[k].get_pins("S")[0].bc().x, self.gnd_position.y)
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self.add_path("metal1", [self.r_nmosL[k].get_pins("S")[0].bc(), offset])
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|
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offset = vector(self.r_nmosR[k].get_pins("S")[0].bc().x, self.gnd_position.y)
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self.add_path("metal1", [self.r_nmosR[k].get_pins("S")[0].bc(), offset])
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""" Source of R transistor / RBL & RBL_bar connection """
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# add contacts to connect source of rt to RBL or RBL_bar
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offsetL = self.r_nmosL[k].get_pins("S")[1].center()
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetL,
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rotate=90)
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offsetR = self.r_nmosR[k].get_pins("S")[1].center()
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self.add_contact_center(layers=("metal1", "via1", "metal2"),
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offset=offsetR,
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rotate=90)
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# add RBL and RBL_bar (simultaneously connects to source of rt)
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self.rbl_positions[k] = vector(self.r_nmosL[k].get_pins("S")[1].center().x - 0.5*drc["minwidth_metal2"], self.botmost_ypos)
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self.add_layout_pin(text="RBL{}".format(k),
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|
layer="metal2",
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|
offset=self.rbl_positions[k],
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|
width=drc["minwidth_metal2"],
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|
height=self.cell_height)
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|
|
|
self.rbl_bar_positions[k] = vector(self.r_nmosR[k].get_pins("S")[1].center().x - 0.5*drc["minwidth_metal2"], self.botmost_ypos)
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|
self.add_layout_pin(text="RBL_bar{}".format(k),
|
|
layer="metal2",
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|
offset=self.rbl_bar_positions[k],
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|
width=drc["minwidth_metal2"],
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|
height=self.cell_height)
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|
|
|
|
|
""" Gate of R transistor / RROW connection """
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|
# add contact to connect gate of rt to RROW (poly to metal2)
|
|
offsetL = vector(lrt_xpos - rot_correct - drc["minwidth_poly"] - 0.5*contact.poly.width, self.r_nmosL[k].get_pins("G")[1].lc().y)
|
|
self.add_contact_center(layers=("poly", "contact", "metal1"),
|
|
offset=offsetL)
|
|
self.add_contact_center(layers=("metal1", "via1", "metal2"),
|
|
offset=offsetL)
|
|
|
|
offsetR = vector(rrt_xpos + drc["minwidth_poly"] + 0.5*contact.poly.width, self.r_nmosR[k].get_pins("G")[1].rc().y)
|
|
self.add_contact_center(layers=("poly", "contact", "metal1"),
|
|
offset=offsetR)
|
|
self.add_contact_center(layers=("metal1", "via1", "metal2"),
|
|
offset=offsetR)
|
|
|
|
# connect gate of rt to contact
|
|
self.add_path("poly", [self.r_nmosL[k].get_pins("G")[1].lc(), offsetL])
|
|
self.add_path("poly", [self.r_nmosR[k].get_pins("G")[1].rc(), offsetR])
|
|
|
|
# add contacts to RROW lines
|
|
row_offsetL = vector(self.r_nmosL[k].get_pins("S")[1].lc().x - drc["minwidth_metal2"] - 0.5*contact.m1m2.width, self.rrow_positions[k].y + 0.5*drc["minwidth_metal1"])
|
|
self.add_contact_center(layers=("metal1", "via1", "metal2"),
|
|
offset=row_offsetL,
|
|
rotate=90)
|
|
|
|
row_offsetR = vector(self.r_nmosR[k].get_pins("S")[1].rc().x + drc["minwidth_metal2"] + 0.5*contact.m1m2.width, self.rrow_positions[k].y + 0.5*drc["minwidth_metal1"])
|
|
self.add_contact_center(layers=("metal1", "via1", "metal2"),
|
|
offset=row_offsetR,
|
|
rotate=90)
|
|
|
|
# connect rt gate contacts to RROW contacts
|
|
self.add_path("metal2", [offsetL, row_offsetL])
|
|
self.add_path("metal2", [offsetR, row_offsetR])
|
|
|
|
|
|
""" Gate of RA transistor / storage connection """
|
|
# add contact to connect gate of rat to output of inverters
|
|
offsetL = vector(lrt_xpos + drc["minwidth_poly"] + 0.5*contact.poly.width, self.r_nmosL[k].get_pins("G")[0].rc().y)
|
|
self.add_contact_center(layers=("poly", "contact", "metal1"),
|
|
offset=offsetL)
|
|
|
|
offsetR = vector(rrt_xpos - rot_correct - drc["minwidth_poly"] - 0.5*contact.poly.width, self.r_nmosR[k].get_pins("G")[0].lc().y)
|
|
self.add_contact_center(layers=("poly", "contact", "metal1"),
|
|
offset=offsetR)
|
|
|
|
# connect gate of rat to contact
|
|
self.add_path("poly", [self.r_nmosL[k].get_pins("G")[0].rc(), offsetL])
|
|
self.add_path("poly", [self.r_nmosR[k].get_pins("G")[0].lc(), offsetR])
|
|
|
|
# connect contact to output of inverters
|
|
midL0 = vector(offsetL.x, self.r_nmosL[k].get_pins("S")[1].uc().y + 1.5*drc["minwidth_metal1"])
|
|
midL1 = vector(self.i_nmosL.get_pin("S").lc().x - 1.5*drc["minwidth_metal1"], self.r_nmosL[0].get_pins("S")[1].uc().y + 1.5*drc["minwidth_metal1"])
|
|
midL2 = vector(self.i_nmosL.get_pin("S").lc().x - 1.5*drc["minwidth_metal1"], self.cross_heightU)
|
|
gate_offsetL = vector(self.i_nmosL.get_pin("D").center().x, self.cross_heightU)
|
|
self.add_path("metal1", [offsetL, midL0, midL1, midL2, gate_offsetL])
|
|
|
|
midR0 = vector(offsetR.x, self.r_nmosR[k].get_pins("S")[1].uc().y + 1.5*drc["minwidth_metal1"])
|
|
midR1 = vector(self.i_nmosR.get_pin("D").rc().x + 1.5*drc["minwidth_metal1"], self.r_nmosR[k].get_pins("S")[1].uc().y + 1.5*drc["minwidth_metal1"])
|
|
midR2 = vector(self.i_nmosR.get_pin("D").rc().x + 1.5*drc["minwidth_metal1"], self.cross_heightU)
|
|
gate_offsetR = vector(self.i_nmosR.get_pin("S").center().x, self.cross_heightU)
|
|
self.add_path("metal1", [offsetR, midR0, midR1, midR2, gate_offsetR])
|
|
|
|
|
|
def extend_well(self):
|
|
""" extend nwell and pwell """
|
|
# extend pwell to encompass i_nmos
|
|
offset = vector(self.leftmost_xpos, self.botmost_ypos)
|
|
well_height = -self.botmost_ypos + self.i_nmos.well_height - drc["well_enclosure_active"]
|
|
self.add_rect(layer="pwell",
|
|
offset=offset,
|
|
width=self.cell_width,
|
|
height=well_height)
|
|
|
|
# extend pwell to encompass r_nmos
|
|
r_well_width = self.num_read*self.r_tile_width
|
|
r_well_height = self.r_nmos.well_width - drc["well_enclosure_active"]
|
|
offset = vector(self.leftmost_xpos, 0)
|
|
self.add_rect(layer="pwell",
|
|
offset=offset,
|
|
width=r_well_width,
|
|
height=r_well_height)
|
|
|
|
offset = vector(-self.leftmost_xpos - r_well_width, 0)
|
|
self.add_rect(layer="pwell",
|
|
offset=offset,
|
|
width=r_well_width,
|
|
height=r_well_height)
|
|
|
|
# extend pwell to encompass w_nmos
|
|
lwt_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"] + self.w_tile_width - self.w_nmos.active_height - drc["well_enclosure_active"])
|
|
rwt_xpos = 1.5*parameter["min_tx_size"] + self.i_nmos.active_width + self.w_tile_width - self.w_nmos.active_height - drc["well_enclosure_active"]
|
|
|
|
w_well_width = -(self.leftmost_xpos - lwt_xpos)
|
|
w_well_height = self.w_nmos.well_width - drc["well_enclosure_active"]
|
|
offset = vector(lwt_xpos - w_well_width, 0)
|
|
self.add_rect(layer="pwell",
|
|
offset=offset,
|
|
width=w_well_width,
|
|
height=w_well_height)
|
|
|
|
offset = vector(rwt_xpos, 0)
|
|
self.add_rect(layer="pwell",
|
|
offset=offset,
|
|
width=w_well_width,
|
|
height=w_well_height)
|
|
|
|
# extend nwell to encompass i_pmos
|
|
lit_xpos = -(self.i_nmos.active_width + 1.5*parameter["min_tx_size"] + drc["well_enclosure_active"])
|
|
it_ypos = self.inv_gap + self.i_nmos.active_height - drc["well_enclosure_active"]
|
|
offset = [lit_xpos,it_ypos]
|
|
well_width = 2*self.i_pmos.active_width + 3*parameter["min_tx_size"] + 2*drc["well_enclosure_active"]
|
|
well_height = self.vdd_position.y - it_ypos + drc["well_enclosure_active"] + drc["minwidth_tx"]
|
|
self.add_rect(layer="nwell",
|
|
offset=offset,
|
|
width=well_width,
|
|
height=well_height)
|
|
|
|
|
|
""" add well contacts """
|
|
# connect pimplants to gnd
|
|
offset = vector(0, self.gnd_position.y + 0.5*drc["minwidth_metal1"])
|
|
self.add_contact_center(layers=("active", "contact", "metal1"),
|
|
offset=offset,
|
|
rotate=90)
|
|
|
|
self.add_rect_center(layer="pimplant",
|
|
offset=offset,
|
|
width=drc["minwidth_tx"],
|
|
height=drc["minwidth_tx"])
|
|
|
|
# connect nimplants to vdd
|
|
offset = vector(0, self.vdd_position.y + 0.5*drc["minwidth_metal1"])
|
|
self.add_contact_center(layers=("active", "contact", "metal1"),
|
|
offset=offset,
|
|
rotate=90)
|
|
|
|
self.add_rect_center(layer="nimplant",
|
|
offset=offset,
|
|
width=drc["minwidth_tx"],
|
|
height=drc["minwidth_tx"])
|
|
|
|
|
|
def add_fail(self):
|
|
# for failing drc
|
|
frail_width = self.well_width = 2*drc["minwidth_metal1"]
|
|
frail_height = self.rail_height = drc["minwidth_metal1"]
|
|
|
|
fail_position = vector(-25*drc["minwidth_tx"], - 1.5 * drc["minwidth_metal1"] - 0.5 * frail_height) # for tiling purposes
|
|
self.add_layout_pin(text="gnd",
|
|
layer="metal1",
|
|
offset=fail_position,
|
|
width=frail_width,
|
|
height=frail_height)
|
|
|
|
fail_position2 = vector(-25*drc["minwidth_tx"], - 0.5 * drc["minwidth_metal1"])
|
|
self.add_layout_pin(text="gnd2",
|
|
layer="metal1",
|
|
offset=fail_position2,
|
|
width=frail_width,
|
|
height=frail_height)
|