# See LICENSE for licensing information. # # Copyright (c) 2016-2019 Regents of the University of California # All rights reserved. # import debug import design from tech import drc import contact from sram_factory import factory from vector import vector from globals import OPTS class dummy_array(design.design): """ Generate a dummy row/column for the replica array. """ def __init__(self, cols, rows, mirror=0, name=""): design.design.__init__(self, name) debug.info(1, "Creating {0} {1} x {2}".format(self.name, rows, cols)) self.add_comment("rows: {0} cols: {1}".format(rows, cols)) self.column_size = cols self.row_size = rows self.mirror = mirror self.create_netlist() if not OPTS.netlist_only: self.create_layout() def create_netlist(self): """ Create and connect the netlist """ self.add_modules() self.add_pins() self.create_instances() def create_layout(self): # We increase it by a well enclosure so the precharges don't overlap our wells self.height = self.row_size*self.dummy_cell.height self.width = self.column_size*self.dummy_cell.width xoffset = 0.0 for col in range(self.column_size): yoffset = 0.0 for row in range(self.row_size): name = "dummy_r{0}_c{1}".format(row, col) if (row+self.mirror) % 2: tempy = yoffset + self.dummy_cell.height dir_key = "MX" else: tempy = yoffset dir_key = "" self.cell_inst[row,col].place(offset=[xoffset, tempy], mirror=dir_key) yoffset += self.dummy_cell.height xoffset += self.dummy_cell.width self.add_layout_pins() self.add_boundary() self.DRC_LVS() def add_pins(self): row_list = self.cell.get_all_wl_names() column_list = self.cell.get_all_bitline_names() for col in range(self.column_size): for cell_column in column_list: self.add_pin(cell_column+"_{0}".format(col), "INOUT") for row in range(self.row_size): for cell_row in row_list: self.add_pin(cell_row+"_{0}".format(row), "INPUT") self.add_pin("vdd", "POWER") self.add_pin("gnd", "GROUND") def add_modules(self): """ Add the modules used in this design """ self.dummy_cell = factory.create(module_type="dummy_bitcell") self.add_mod(self.dummy_cell) self.cell = factory.create(module_type="bitcell") def get_bitcell_pins(self, col, row): """ Creates a list of connections in the bitcell, indexed by column and row, for instance use in bitcell_array """ bitcell_pins = [] pin_names = self.cell.get_all_bitline_names() for pin in pin_names: bitcell_pins.append(pin+"_{0}".format(col)) pin_names = self.cell.get_all_wl_names() for pin in pin_names: bitcell_pins.append(pin+"_{0}".format(row)) bitcell_pins.append("vdd") bitcell_pins.append("gnd") return bitcell_pins def create_instances(self): """ Create the module instances used in this design """ self.cell_inst = {} for col in range(self.column_size): for row in range(self.row_size): name = "bit_r{0}_c{1}".format(row, col) self.cell_inst[row,col]=self.add_inst(name=name, mod=self.dummy_cell) self.connect_inst(self.get_bitcell_pins(col, row)) def add_layout_pins(self): """ Add the layout pins """ row_list = self.cell.get_all_wl_names() column_list = self.cell.get_all_bitline_names() for col in range(self.column_size): for cell_column in column_list: bl_pin = self.cell_inst[0,col].get_pin(cell_column) self.add_layout_pin(text=cell_column+"_{0}".format(col), layer="metal2", offset=bl_pin.ll(), width=bl_pin.width(), height=self.height) for row in range(self.row_size): for cell_row in row_list: wl_pin = self.cell_inst[row,0].get_pin(cell_row) self.add_layout_pin(text=cell_row+"_{0}".format(row), layer="metal1", offset=wl_pin.ll(), width=self.width, height=wl_pin.height()) # For every second row and column, add a via for gnd and vdd for row in range(self.row_size): for col in range(self.column_size): inst = self.cell_inst[row,col] for pin_name in ["vdd", "gnd"]: for pin in inst.get_pins(pin_name): self.add_power_pin(name=pin_name, loc=pin.center(), vertical=True, start_layer=pin.layer) def input_load(self): wl_wire = self.gen_wl_wire() return wl_wire.return_input_cap() def get_wordline_cin(self): """Get the relative input capacitance from the wordline connections in all the bitcell""" #A single wordline is connected to all the bitcells in a single row meaning the capacitance depends on the # of columns bitcell_wl_cin = self.cell.get_wl_cin() total_cin = bitcell_wl_cin * self.column_size return total_cin