import contact import design import debug from tech import drc, parameter, spice, info from ptx import ptx from vector import vector from globals import OPTS class pgate(design.design): """ This is a module that implements some shared functions for parameterized gates. """ def __init__(self, name): """ Creates a generic cell """ design.design.__init__(self, name) def connect_pin_to_rail(self,inst,pin,supply): """ Conencts a ptx pin to a supply rail. """ source_pin = inst.get_pin(pin) supply_pin = self.get_pin(supply) if supply_pin.overlaps(source_pin): return if supply=="gnd": height=supply_pin.by()-source_pin.by() elif supply=="vdd": height=supply_pin.uy()-source_pin.by() else: debug.error("Invalid supply name.",-1) if abs(height)>0: self.add_rect(layer="metal1", offset=source_pin.ll(), height=height, width=source_pin.width()) def route_input_gate(self, pmos_inst, nmos_inst, ypos, name, position="left", rotate=90): """ Route the input gate to the left side of the cell for access. Position specifies to place the contact the left, center, or right of gate. """ nmos_gate_pin = nmos_inst.get_pin("G") pmos_gate_pin = pmos_inst.get_pin("G") # Check if the gates are aligned and give an error if they aren't! debug.check(nmos_gate_pin.ll().x==pmos_gate_pin.ll().x, "Connecting unaligned gates not supported.") # Pick point on the left of NMOS and connect down to PMOS nmos_gate_pos = nmos_gate_pin.ll() + vector(0.5*self.poly_width,0) pmos_gate_pos = vector(nmos_gate_pos.x,pmos_gate_pin.bc().y) self.add_path("poly",[nmos_gate_pos,pmos_gate_pos]) # Add the via to the cell midpoint along the gate left_gate_offset = vector(nmos_gate_pin.lx(),ypos) # Center is completely symmetric. if rotate==90: contact_width = contact.poly.height contact_m1_width = contact.poly.second_layer_height contact_m1_height = contact.poly.second_layer_width else: contact_width = contact.poly.width contact_m1_width = contact.poly.second_layer_width contact_m1_height = contact.poly.second_layer_height if position=="center": contact_offset = left_gate_offset + vector(0.5*self.poly_width, 0) elif position=="left": contact_offset = left_gate_offset - vector(0.5*contact_width - 0.5*self.poly_width, 0) elif position=="right": contact_offset = left_gate_offset + vector(0.5*contact.width + 0.5*self.poly_width, 0) else: debug.error("Invalid contact placement option.", -1) self.add_contact_center(layers=("poly", "contact", "metal1"), offset=contact_offset, rotate=rotate) # self.add_layout_pin_segment_center(text=name, # layer="metal1", # start=left_gate_offset.scale(0,1), # end=left_gate_offset) self.add_layout_pin_rect_center(text=name, layer="metal1", offset=contact_offset, width=contact_m1_width, height=contact_m1_height) # This is to ensure that the contact is connected to the gate mid_point = contact_offset.scale(0.5,1)+left_gate_offset.scale(0.5,0) self.add_rect_center(layer="poly", offset=mid_point, height=contact.poly.first_layer_width, width=left_gate_offset.x-contact_offset.x) def extend_wells(self, middle_position): """ Extend the n/p wells to cover whole cell """ # Add a rail width to extend the well to the top of the rail max_y_offset = self.height + 0.5*self.m1_width self.nwell_position = middle_position nwell_height = max_y_offset - middle_position.y if info["has_nwell"]: self.add_rect(layer="nwell", offset=middle_position, width=self.well_width, height=nwell_height) self.add_rect(layer="vtg", offset=self.nwell_position, width=self.well_width, height=nwell_height) pwell_position = vector(0,-0.5*self.m1_width) pwell_height = middle_position.y-pwell_position.y if info["has_pwell"]: self.add_rect(layer="pwell", offset=pwell_position, width=self.well_width, height=pwell_height) self.add_rect(layer="vtg", offset=pwell_position, width=self.well_width, height=pwell_height) def add_nwell_contact(self, pmos, pmos_pos): """ Add an nwell contact next to the given pmos device. """ layer_stack = ("active", "contact", "metal1") # To the right a spacing away from the pmos right active edge contact_xoffset = pmos_pos.x + pmos.active_width + drc["active_to_body_active"] # Must be at least an well enclosure of active down from the top of the well # OR align the active with the top of PMOS active. max_y_offset = self.height + 0.5*self.m1_width contact_yoffset = min(pmos_pos.y + pmos.active_height - pmos.active_contact.first_layer_height, max_y_offset - pmos.active_contact.first_layer_height/2 - self.well_enclose_active) contact_offset = vector(contact_xoffset, contact_yoffset) # Offset by half a contact in x and y contact_offset += vector(0.5*pmos.active_contact.first_layer_width, 0.5*pmos.active_contact.first_layer_height) self.nwell_contact=self.add_contact_center(layers=layer_stack, offset=contact_offset, implant_type="n", well_type="n") self.add_rect_center(layer="metal1", offset=contact_offset + vector(0,0.5*(self.height-contact_offset.y)), width=self.nwell_contact.mod.second_layer_width, height=self.height - contact_offset.y) # Now add the full active and implant for the PMOS #active_offset = pmos_pos + vector(pmos.active_width,0) # This might be needed if the spacing between the actives is not satisifed # self.add_rect(layer="active", # offset=active_offset, # width=pmos.active_contact.width, # height=pmos.active_height) # we need to ensure implants don't overlap and are spaced far enough apart # implant_spacing = self.implant_space+self.implant_enclose_active # implant_offset = active_offset + vector(implant_spacing,0) - vector(0,self.implant_enclose_active) # implant_width = pmos.active_contact.width + 2*self.implant_enclose_active # implant_height = pmos.active_height + 2*self.implant_enclose_active # self.add_rect(layer="nimplant", # offset=implant_offset, # width=implant_width, # height=implant_height) # Return the top of the well def add_pwell_contact(self, nmos, nmos_pos): """ Add an pwell contact next to the given nmos device. """ layer_stack = ("active", "contact", "metal1") pwell_position = vector(0,-0.5*self.m1_width) # To the right a spacing away from the nmos right active edge contact_xoffset = nmos_pos.x + nmos.active_width + drc["active_to_body_active"] # Must be at least an well enclosure of active up from the bottom of the well contact_yoffset = max(nmos_pos.y, self.well_enclose_active - nmos.active_contact.first_layer_height/2) contact_offset = vector(contact_xoffset, contact_yoffset) # Offset by half a contact contact_offset += vector(0.5*nmos.active_contact.first_layer_width, 0.5*nmos.active_contact.first_layer_height) self.pwell_contact=self.add_contact_center(layers=layer_stack, offset=contact_offset, implant_type="p", well_type="p") self.add_rect_center(layer="metal1", offset=contact_offset.scale(1,0.5), width=self.pwell_contact.mod.second_layer_width, height=contact_offset.y) # Now add the full active and implant for the NMOS # active_offset = nmos_pos + vector(nmos.active_width,0) # This might be needed if the spacing between the actives is not satisifed # self.add_rect(layer="active", # offset=active_offset, # width=nmos.active_contact.width, # height=nmos.active_height) # implant_spacing = self.implant_space+self.implant_enclose_active # implant_offset = active_offset + vector(implant_spacing,0) - vector(0,self.implant_enclose_active) # implant_width = nmos.active_contact.width + 2*self.implant_enclose_active # implant_height = nmos.active_height + 2*self.implant_enclose_active # self.add_rect(layer="pimplant", # offset=implant_offset, # width=implant_width, # height=implant_height)