mirror of https://github.com/VLSIDA/OpenRAM.git
95 lines
3.5 KiB
Python
95 lines
3.5 KiB
Python
# See LICENSE for licensing information.
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#
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# Copyright (c) 2016-2024 Regents of the University of California and The Board
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# of Regents for the Oklahoma Agricultural and Mechanical College
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# (acting for and on behalf of Oklahoma State University)
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# All rights reserved.
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#
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from openram.base import design
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from openram.base import vector
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from openram import OPTS
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from openram.sram_factory import factory
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from openram.tech import drc
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class rom_poly_tap(design):
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def __init__(self, name="", cell_name=None, tx_type="nmos", strap_layer="m2", add_active_tap=False, place_poly=False):
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super().__init__(name, cell_name)
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self.strap_layer = strap_layer
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self.tx_type = tx_type
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self.add_tap = add_active_tap
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if place_poly is None:
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self.place_poly = add_active_tap
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else:
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self.place_poly = place_poly
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self.pitch_offset = 0
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self.create_netlist()
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self.create_layout()
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def create_netlist(self):
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#for layout constants
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self.dummy = factory.create(module_type="rom_base_cell")
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self.pmos = factory.create(module_type="ptx", tx_type="pmos")
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def create_layout(self):
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self.place_via()
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if self.add_tap or self.place_poly:
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self.place_active_tap()
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self.add_boundary()
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def add_boundary(self):
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contact_width = self.poly_contact.width
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self.height = self.dummy.height
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self.width = contact_width + self.pitch_offset
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super().add_boundary()
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def place_via(self):
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contact_width = self.poly_contact.width
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contact_y = self.dummy.cell_inst.width * 0.5 - 0.5 * self.contact_width - self.active_enclose_contact
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self.contact_x_offset = 0
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contact_x = contact_width * 0.5 + self.contact_x_offset
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self.contact_offset = vector(contact_x, contact_y)
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self.via = self.add_via_stack_center(from_layer="poly",
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to_layer=self.strap_layer,
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offset=self.contact_offset)
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self.add_layout_pin_rect_center("poly_tap", self.strap_layer, self.contact_offset)
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def extend_poly(self):
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y_offset = 0
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if self.tx_type == "pmos":
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y_offset = -self.height
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start = self.via.center() + vector(0, y_offset)
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if self.place_poly:
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self.add_segment_center("poly", start, vector(self.via.cx() + self.pitch_offset, self.via.cy() + y_offset))
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self.add_segment_center("poly", start, vector(0, self.via.cy() + y_offset))
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def place_active_tap(self):
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gap = self.poly_extend_active - 0.5 * ( self.active_contact.height - self.poly_contact.width )
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offset = self.active_space - gap
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tap_x = self.via.cx() + offset
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tap_y = self.via.cy() + self.dummy.width * 0.5
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contact_pos = vector(tap_x, tap_y)
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# This pitch offset is used throughout the memory bank to make sure the pitch of the decoder outputs matches the pitch of the array inputs
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self.pitch_offset = 0.5 * self.active_contact.width + self.active_space + 0.5 * self.contact_width + self.active_enclose_contact
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if self.tx_type == "nmos" and self.add_tap:
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self.add_via_center(layers=self.active_stack,
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offset=contact_pos,
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implant_type="p",
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well_type="p",
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directions="nonpref")
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self.add_layout_pin_rect_center("active_tap", self.active_stack[2], contact_pos)
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