Merge pull request #282 from ruhai-lin/stable

Attempt to fix LVS mismatch and SRAM creation with banks for sky130

Author: jcirimel

compiler/characterizer/delay.py

@@ -1388,11 +1388,15 @@ def get_delay_lists(self, value_dict):
     def calculate_inverse_address(self):
         """Determine dummy test address based on probe address and column mux size."""
 
-        # The inverse address needs to share the same bitlines as the probe address as the trimming will remove all other bitlines
+        # The inverse address needs to share the same bitlines as the probe address as the trimming will remove all other bitlines.
         # This is only an issue when there is a column mux and the address maps to different bitlines.
         column_addr = self.get_column_addr() # do not invert this part
         inverse_address = ""
-        for c in self.probe_address[self.sram.col_addr_size:]: # invert everything else
+        if self.sram.col_addr_size > 0:
+            row_address = self.probe_address[:-self.sram.col_addr_size]
+        else:
+            row_address = self.probe_address
+        for c in row_address: # invert row bits only
             if c=="0":
                 inverse_address += "1"
             elif c=="1":

compiler/characterizer/simulation.py

@@ -126,8 +126,10 @@ def set_probe(self, probe_address, probe_data):
     def get_data_bit_column_number(self, probe_address, probe_data):
         """Calculates bitline column number of data bit under test using bit position and mux size"""
 
-        if self.sram.col_addr_size>0:
-            col_address = int(probe_address[0:self.sram.col_addr_size], 2)
+        # Address pins are ordered a*_0 ... a*_N, where a*_0 is the LSB.
+        # So the column mux select bits are the rightmost bits in the binary address string.
+        if self.sram.col_addr_size > 0:
+            col_address = int(probe_address[-self.sram.col_addr_size:], 2)
         else:
             col_address = 0
         bl_column = int(self.sram.words_per_row * probe_data + col_address)
@@ -136,7 +138,11 @@ def get_data_bit_column_number(self, probe_address, probe_data):
     def get_address_row_number(self, probe_address):
         """Calculates wordline row number of data bit under test using address and column mux size"""
 
-        return int(probe_address[self.sram.col_addr_size:], 2)
+        if self.sram.col_addr_size > 0:
+            row_address = probe_address[:-self.sram.col_addr_size]
+        else:
+            row_address = probe_address
+        return int(row_address, 2) if row_address else 0
 
     def add_control_one_port(self, port, op):
         """Appends control signals for operation to a given port"""
@@ -484,7 +490,9 @@ def gen_pin_names(self, port_signal_names, port_info, abits, dbits):
 
     def get_column_addr(self):
         """Returns column address of probe bit"""
-        return self.probe_address[:self.sram.col_addr_size]
+        if self.sram.col_addr_size == 0:
+            return ""
+        return self.probe_address[-self.sram.col_addr_size:]
 
     def add_graph_exclusions(self):
         """

compiler/characterizer/trim_spice.py

@@ -56,12 +56,15 @@ def trim(self, address, data_bit):
         # Always start fresh if we do multiple reductions
         self.sp_buffer = self.spice
 
-        # Split up the address and convert to an int
-        wl_address = int(address[self.col_addr_size:], 2)
+        # Address pins are ordered with bit 0 as LSB, so mux column bits
+        # are the rightmost bits in the binary address string.
         if self.col_addr_size > 0:
-            col_address = int(address[0:self.col_addr_size], 2)
+            row_address = address[:-self.col_addr_size]
+            col_address = int(address[-self.col_addr_size:], 2)
         else:
+            row_address = address
             col_address = 0
+        wl_address = int(row_address, 2) if row_address else 0
 
         # 1. Keep cells in the bitcell array based on WL and BL
         wl_name = "wl_{}".format(wl_address)

technology/sky130/custom/sky130_bitcell_base_array.py

@@ -100,14 +100,15 @@ def get_col_cap_pins(self, row, col):
         strap_pins = []
         for port in self.all_ports:
             strap_pins.extend([x for x in self.get_bitline_names(port) if "bl" in x and x.endswith("_{0}".format(col))])
-        strap_pins.extend(["vdd", "gnd"])
         for port in self.all_ports:
             strap_pins.extend([x for x in self.get_bitline_names(port) if "br" in x and x.endswith("_{0}".format(col))])
+        # col_cap_1port_bitcell port order:
+        # [bl, br, vdd, gnd, vpb, vnb, gate]
+        strap_pins.extend(["vdd", "gnd", "vdd", "gnd"])
         if row == 0:
-            strap_pins.extend(["top_gate"])
+            strap_pins.append("top_gate")
         else:
-            strap_pins.extend(["bot_gate"])
-        strap_pins.extend(["vdd", "gnd"])
+            strap_pins.append("bot_gate")
         return strap_pins
 
     def get_row_cap_pins(self, row, col):

technology/sky130/custom/sky130_col_cap_array.py

@@ -75,12 +75,12 @@ def create_instances(self):
                 row_layout.append(self.colend1)
                 self.cell_inst[col]=self.add_inst(name=name, mod=self.colend1)
                 pins.append("fake_bl_{}".format(bitline))
+                pins.append("fake_br_{}".format(bitline))
                 pins.append("vdd")
                 pins.append("gnd")
-                pins.append("fake_br_{}".format(bitline))
-                pins.append("gate")
                 pins.append("vdd")
                 pins.append("gnd")
+                pins.append("gate")
                 bitline += 1
             elif col % 4 == 1:
                 row_layout.append(self.colend2)
@@ -92,12 +92,12 @@ def create_instances(self):
                 row_layout.append(self.colend1)
                 self.cell_inst[col]=self.add_inst(name=name, mod=self.colend1)
                 pins.append("fake_bl_{}".format(bitline))
+                pins.append("fake_br_{}".format(bitline))
                 pins.append("vdd")
                 pins.append("gnd")
-                pins.append("fake_br_{}".format(bitline))
-                pins.append("gate")
                 pins.append("vdd")
                 pins.append("gnd")
+                pins.append("gate")
                 bitline += 1
             elif col % 4 ==3:
                 row_layout.append(self.colend2)