# See LICENSE for licensing information. # # Copyright (c) 2016-2023 Regents of the University of California and The Board # of Regents for the Oklahoma Agricultural and Mechanical College # (acting for and on behalf of Oklahoma State University) # All rights reserved. # from openram import debug from openram.tech import drc, spice from openram.sram_factory import factory from openram import OPTS from .bitcell_base_array import bitcell_base_array from .pattern import pattern from openram.base import geometry, instance from math import ceil class bitcell_array(bitcell_base_array): """ Creates a rows x cols array of memory cells. Assumes bit-lines and word lines are connected by abutment. """ def __init__(self, rows, cols, column_offset=0, name=""): super().__init__(rows=rows, cols=cols, column_offset=column_offset, name=name) debug.info(1, "Creating {0} {1} x {2}".format(self.name, rows, cols)) self.add_comment("rows: {0} cols: {1}".format(rows, cols)) # This will create a default set of bitline/wordline names self.create_all_bitline_names() self.create_all_wordline_names() self.create_netlist() if not OPTS.netlist_only: self.create_layout() # We don't offset this because we need to align # the replica bitcell in the control logic # self.offset_all_coordinates() def create_netlist(self): """ Create and connect the netlist """ self.add_modules() self.add_pins() self.create_instances() def create_layout(self): self.place_array() self.add_layout_pins() self.route_supplies() self.add_boundary() self.DRC_LVS() def add_modules(self): """ Add the modules used in this design """ self.cell = factory.create(module_type=OPTS.bitcell) def create_instances(self): self.cell_inst={} if self.cell.mirror.y: core_block = [[0 for x in range(2)] for y in range(2)] core_block[0][0] = geometry.instance("core_0_0", mod=self.cell, is_bitcell=True) core_block[1][0] = geometry.instance("core_1_0", mod=self.cell, is_bitcell=True, mirror='MX') core_block[0][1] = geometry.instance("core_0_1", mod=self.cell, is_bitcell=True, mirror='MY') core_block[1][1] = geometry.instance("core_1_1", mod=self.cell, is_bitcell=True, mirror='XY') else: core_block = [[0 for x in range(1)] for y in range(2)] core_block[0][0] = geometry.instance("core_0_0", mod=self.cell, is_bitcell=True) core_block[1][0] = geometry.instance("core_1_0", mod=self.cell, is_bitcell=True, mirror='MX') self.pattern = pattern(self, "bitcell_array", core_block, num_rows=self.row_size, num_cols=self.column_size,name_template="bit_r{0}_c{1}") self.pattern.connect_array() for key in self.cell_inst.keys(): if key != (0,0): self.trim_insts.add(self.cell_inst[key].name) def analytical_power(self, corner, load): """Power of Bitcell array and bitline in nW.""" # Dynamic Power from Bitline bl_wire = self.gen_bl_wire() cell_load = 2 * bl_wire.return_input_cap() bl_swing = OPTS.rbl_delay_percentage freq = spice["default_event_frequency"] bitline_dynamic = self.calc_dynamic_power(corner, cell_load, freq, swing=bl_swing) # Calculate the bitcell power which currently only includes leakage cell_power = self.cell.analytical_power(corner, load) # Leakage power grows with entire array and bitlines. total_power = self.return_power(cell_power.dynamic + bitline_dynamic * self.column_size, cell_power.leakage * self.column_size * self.row_size) return total_power def gen_wl_wire(self): if OPTS.netlist_only: width = 0 else: width = self.width wl_wire = self.generate_rc_net(int(self.column_size), width, drc("minwidth_m1")) # 2 access tx gate per cell wl_wire.wire_c = 2 * spice["min_tx_gate_c"] + wl_wire.wire_c return wl_wire def gen_bl_wire(self): if OPTS.netlist_only: height = 0 else: height = self.height bl_pos = 0 bl_wire = self.generate_rc_net(int(self.row_size - bl_pos), height, drc("minwidth_m1")) # 1 access tx d/s per cell bl_wire.wire_c =spice["min_tx_drain_c"] + bl_wire.wire_c return bl_wire def graph_exclude_bits(self, targ_row=None, targ_col=None): """ Excludes bits in column from being added to graph except target """ # Function is not robust with column mux configurations for row in range(self.row_size): for col in range(self.column_size): if row == targ_row and col == targ_col: continue self.graph_inst_exclude.add(self.cell_inst[row, col]) def get_cell_name(self, inst_name, row, col): """Gets the spice name of the target bitcell.""" return inst_name + "{}x".format(OPTS.hier_seperator) + self.cell_inst[row, col].name, self.cell_inst[row, col]