mirror of https://github.com/VLSIDA/OpenRAM.git
213 lines
8.0 KiB
Python
213 lines
8.0 KiB
Python
from tech import drc, parameter
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import debug
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import design
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import contact
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from math import log
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from math import sqrt
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import math
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from pinv import pinv
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from pnand2 import pnand2
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from vector import vector
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from globals import OPTS
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class wordline_driver(design.design):
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"""
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Creates a Wordline Driver
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Generates the wordline-driver to drive the bitcell
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"""
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def __init__(self, rows):
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design.design.__init__(self, "wordline_driver")
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self.rows = rows
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self.add_pins()
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self.design_layout()
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self.offset_all_coordinates()
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self.DRC_LVS()
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def add_pins(self):
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# inputs to wordline_driver.
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for i in range(self.rows):
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self.add_pin("in[{0}]".format(i))
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# Outputs from wordline_driver.
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for i in range(self.rows):
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self.add_pin("wl[{0}]".format(i))
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self.add_pin("en")
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self.add_pin("vdd")
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self.add_pin("gnd")
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def design_layout(self):
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self.add_layout()
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self.offsets_of_gates()
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self.create_layout()
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def add_layout(self):
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self.inv = pinv()
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self.add_mod(self.inv)
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self.inv_no_output = pinv(route_output=False)
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self.add_mod(self.inv_no_output)
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self.nand2 = pnand2()
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self.add_mod(self.nand2)
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def offsets_of_gates(self):
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self.x_offset0 = 2*self.m1_width + 5*self.m1_space
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self.x_offset1 = self.x_offset0 + self.inv.width
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self.x_offset2 = self.x_offset1 + self.nand2.width
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self.width = self.x_offset2 + self.inv.width
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self.height = self.inv.height * self.rows
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def create_layout(self):
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# Wordline enable connection
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en_pin=self.add_layout_pin(text="en",
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layer="metal2",
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offset=[self.m1_width + 2*self.m1_space,0],
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width=self.m2_width,
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height=self.height)
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self.add_layout_pin(text="gnd",
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layer="metal1",
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offset=[0, -0.5*self.m1_width],
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width=self.x_offset0,
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height=self.m1_width)
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for row in range(self.rows):
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name_inv1 = "wl_driver_inv_en{}".format(row)
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name_nand = "wl_driver_nand{}".format(row)
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name_inv2 = "wl_driver_inv{}".format(row)
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inv_nand2B_connection_height = (abs(self.inv.get_pin("Z").ll().y
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- self.nand2.get_pin("B").ll().y)
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+ self.m1_width)
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if (row % 2):
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y_offset = self.inv.height*(row + 1)
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inst_mirror = "MX"
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cell_dir = vector(0,-1)
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m1tm2_rotate=270
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m1tm2_mirror="R0"
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else:
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y_offset = self.inv.height*row
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inst_mirror = "R0"
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cell_dir = vector(0,1)
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m1tm2_rotate=90
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m1tm2_mirror="MX"
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name_inv1_offset = [self.x_offset0, y_offset]
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nand2_offset=[self.x_offset1, y_offset]
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inv2_offset=[self.x_offset2, y_offset]
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base_offset = vector(self.width, y_offset)
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# Extend vdd and gnd of wordline_driver
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yoffset = (row + 1) * self.inv.height - 0.5 * self.m1_width
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if (row % 2):
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pin_name = "gnd"
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else:
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pin_name = "vdd"
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self.add_layout_pin(text=pin_name,
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layer="metal1",
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offset=[0, yoffset],
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width=self.x_offset0,
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height=self.m1_width)
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# add inv1 based on the info above
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inv1_inst=self.add_inst(name=name_inv1,
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mod=self.inv_no_output,
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offset=name_inv1_offset,
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mirror=inst_mirror )
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self.connect_inst(["en",
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"en_bar[{0}]".format(row),
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"vdd", "gnd"])
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# add nand 2
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nand_inst=self.add_inst(name=name_nand,
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mod=self.nand2,
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offset=nand2_offset,
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mirror=inst_mirror)
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self.connect_inst(["en_bar[{0}]".format(row),
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"in[{0}]".format(row),
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"net[{0}]".format(row),
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"vdd", "gnd"])
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# add inv2
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inv2_inst=self.add_inst(name=name_inv2,
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mod=self.inv,
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offset=inv2_offset,
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mirror=inst_mirror)
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self.connect_inst(["net[{0}]".format(row),
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"wl[{0}]".format(row),
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"vdd", "gnd"])
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# en connection
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a_pin = inv1_inst.get_pin("A")
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a_pos = a_pin.lc()
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clk_offset = vector(en_pin.bc().x,a_pos.y)
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self.add_segment_center(layer="metal1",
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start=clk_offset,
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end=a_pos)
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self.add_via_center(layers=("metal1", "via1", "metal2"),
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offset=clk_offset)
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# first inv to nand2 A
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zb_pos = inv1_inst.get_pin("Z").bc()
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zu_pos = inv1_inst.get_pin("Z").uc()
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bl_pos = nand_inst.get_pin("A").lc()
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br_pos = nand_inst.get_pin("A").rc()
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self.add_path("metal1", [zb_pos, zu_pos, bl_pos, br_pos])
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# Nand2 out to 2nd inv
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zr_pos = nand_inst.get_pin("Z").rc()
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al_pos = inv2_inst.get_pin("A").lc()
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# ensure the bend is in the middle
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mid1_pos = vector(0.5*(zr_pos.x+al_pos.x), zr_pos.y)
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mid2_pos = vector(0.5*(zr_pos.x+al_pos.x), al_pos.y)
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self.add_path("metal1", [zr_pos, mid1_pos, mid2_pos, al_pos])
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# connect the decoder input pin to nand2 B
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b_pin = nand_inst.get_pin("B")
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b_pos = b_pin.lc()
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# needs to move down since B nand input is nearly aligned with A inv input
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up_or_down = self.m2_space if row%2 else -self.m2_space
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input_offset = vector(0,b_pos.y + up_or_down)
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mid_via_offset = vector(clk_offset.x,input_offset.y) + vector(0.5*self.m2_width+self.m2_space+0.5*contact.m1m2.width,0)
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# must under the clk line in M1
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self.add_layout_pin_segment_center(text="in[{0}]".format(row),
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layer="metal1",
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start=input_offset,
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end=mid_via_offset)
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self.add_via_center(layers=("metal1", "via1", "metal2"),
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offset=mid_via_offset)
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# now connect to the nand2 B
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self.add_path("metal2", [mid_via_offset, b_pos])
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self.add_via_center(layers=("metal1", "via1", "metal2"),
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offset=b_pos - vector(0.5*contact.m1m2.height,0),
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rotate=90)
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# output each WL on the right
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wl_offset = inv2_inst.get_pin("Z").rc()
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self.add_layout_pin_segment_center(text="wl[{0}]".format(row),
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layer="metal1",
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start=wl_offset,
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end=wl_offset-vector(self.m1_width,0))
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def analytical_delay(self, slew, load=0):
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# decode -> net
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decode_t_net = self.nand2.analytical_delay(slew, self.inv.input_load())
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# net -> wl
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net_t_wl = self.inv.analytical_delay(decode_t_net.slew, load)
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return decode_t_net + net_t_wl
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def input_load(self):
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return self.nand2.input_load()
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