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Optimizations to pbitcell spacings

This commit is contained in:
Michael Timothy Grimes 2018-11-01 07:58:20 -07:00
parent 98a00f985b
commit dc96d86082
2 changed files with 25 additions and 18 deletions
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1
compiler/base/design.py
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@ -39,6 +39,7 @@ class design(hierarchy_design):
self.m3_width = drc("minwidth_metal3")
self.m3_space = drc("metal3_to_metal3")
self.active_width = drc("minwidth_active")
self.active_space = drc("active_to_body_active")
self.contact_width = drc("minwidth_contact")
self.poly_to_active = drc("poly_to_active")

42
compiler/bitcells/pbitcell.py
View File

@ -197,8 +197,10 @@ class pbitcell(design.design):
self.inverter_nmos_ypos = self.port_ypos
# spacing between ports
self.bitline_offset = -self.active_width + 0.5*contact.m1m2.height + self.m2_space + self.m2_width
self.port_spacing = self.bitline_offset + self.m2_space
self.bitline_offset = -0.5*self.readwrite_nmos.active_width + 0.5*contact.m1m2.height + self.m2_space + self.m2_width
m2_constraint = self.bitline_offset + self.m2_space + 0.5*contact.m1m2.height - 0.5*self.readwrite_nmos.active_width
self.rw_w_spacing = max(self.active_space, self.m1_space, m2_constraint)
self.r_spacing = self.bitline_offset + self.m2_space
# spacing between cross coupled inverters
self.inverter_to_inverter_spacing = contact.poly.height + self.m1_space
@ -236,9 +238,9 @@ class pbitcell(design.design):
self.topmost_ypos = self.inverter_nmos_ypos + self.inverter_nmos.active_height + self.inverter_gap + self.inverter_pmos.active_height + self.vdd_offset
self.leftmost_xpos = -0.5*self.inverter_to_inverter_spacing - self.inverter_nmos.active_width \
- self.num_rw_ports*(self.readwrite_nmos.active_width + self.port_spacing) \
- self.num_w_ports*(self.write_nmos.active_width + self.port_spacing) \
- self.num_r_ports*(self.read_port_width + self.port_spacing) \
- self.num_rw_ports*(self.readwrite_nmos.active_width + self.rw_w_spacing) \
- self.num_w_ports*(self.write_nmos.active_width + self.rw_w_spacing) \
- self.num_r_ports*(self.read_port_width + self.r_spacing) \
- self.bitline_offset - 0.5*self.m2_width
self.width = -2*self.leftmost_xpos
@ -370,11 +372,11 @@ class pbitcell(design.design):
for k in range(0,self.num_rw_ports):
# calculate read/write transistor offsets
left_readwrite_transistor_xpos = self.left_building_edge \
- (k+1)*self.port_spacing \
- (k+1)*self.rw_w_spacing \
- (k+1)*self.readwrite_nmos.active_width
right_readwrite_transistor_xpos = self.right_building_edge \
+ (k+1)*self.port_spacing \
+ (k+1)*self.rw_w_spacing \
+ k*self.readwrite_nmos.active_width
# place read/write transistors
@ -392,7 +394,7 @@ class pbitcell(design.design):
height=self.m1_width)
# add pins for RWBL and RWBR
rwbl_xpos = left_readwrite_transistor_xpos - self.bitline_offset + self.m2_width
rwbl_xpos = left_readwrite_transistor_xpos - self.bitline_offset + 0.5*self.m2_width
self.rwbl_positions[k] = vector(rwbl_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.rw_bl_names[k],
layer="metal2",
@ -400,7 +402,7 @@ class pbitcell(design.design):
width=drc["minwidth_metal2"],
height=self.height)
rwbr_xpos = right_readwrite_transistor_xpos + self.readwrite_nmos.active_width + self.bitline_offset - self.m2_width
rwbr_xpos = right_readwrite_transistor_xpos + self.readwrite_nmos.active_width + self.bitline_offset - 0.5*self.m2_width
self.rwbr_positions[k] = vector(rwbr_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.rw_br_names[k],
layer="metal2",
@ -447,11 +449,11 @@ class pbitcell(design.design):
# Add transistors
# calculate write transistor offsets
left_write_transistor_xpos = self.left_building_edge \
- (k+1)*self.port_spacing \
- (k+1)*self.rw_w_spacing \
- (k+1)*self.write_nmos.active_width
right_write_transistor_xpos = self.right_building_edge \
+ (k+1)*self.port_spacing \
+ (k+1)*self.rw_w_spacing \
+ k*self.write_nmos.active_width
# add write transistors
@ -469,7 +471,7 @@ class pbitcell(design.design):
height=self.m1_width)
# add pins for WBL and WBR
wbl_xpos = left_write_transistor_xpos - self.bitline_offset + self.m2_width
wbl_xpos = left_write_transistor_xpos - self.bitline_offset + 0.5*self.m2_width
self.wbl_positions[k] = vector(wbl_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.w_bl_names[k],
layer="metal2",
@ -477,7 +479,7 @@ class pbitcell(design.design):
width=drc["minwidth_metal2"],
height=self.height)
wbr_xpos = right_write_transistor_xpos + self.write_nmos.active_width + self.bitline_offset - self.m2_width
wbr_xpos = right_write_transistor_xpos + self.write_nmos.active_width + self.bitline_offset - 0.5*self.m2_width
self.wbr_positions[k] = vector(wbr_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.w_br_names[k],
layer="metal2",
@ -541,11 +543,11 @@ class pbitcell(design.design):
for k in range(0,self.num_r_ports):
# calculate transistor offsets
left_read_transistor_xpos = self.left_building_edge \
- (k+1)*self.port_spacing \
- (k+1)*self.r_spacing \
- (k+1)*self.read_port_width
right_read_transistor_xpos = self.right_building_edge \
+ (k+1)*self.port_spacing \
+ (k+1)*self.r_spacing \
+ k*self.read_port_width
# add read-access transistors
@ -568,7 +570,7 @@ class pbitcell(design.design):
height=self.m1_width)
# add pins for RBL and RBR
rbl_xpos = left_read_transistor_xpos - self.bitline_offset + self.m2_width
rbl_xpos = left_read_transistor_xpos - self.bitline_offset + 0.5*self.m2_width
self.rbl_positions[k] = vector(rbl_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.r_bl_names[k],
layer="metal2",
@ -576,7 +578,7 @@ class pbitcell(design.design):
width=drc["minwidth_metal2"],
height=self.height)
rbr_xpos = right_read_transistor_xpos + self.read_port_width + self.bitline_offset - self.m2_width
rbr_xpos = right_read_transistor_xpos + self.read_port_width + self.bitline_offset - 0.5*self.m2_width
self.rbr_positions[k] = vector(rbr_xpos, self.center_ypos)
self.add_layout_pin_rect_center(text=self.r_br_names[k],
layer="metal2",
@ -692,7 +694,11 @@ class pbitcell(design.design):
self.add_contact_center(layers=("metal1", "via1", "metal2"),
offset=position)
supply_offset = vector(position.x, self.gnd_position.y)
if position.x > 0:
contact_correct = 0.5*contact.m1m2.height
else:
contact_correct = -0.5*contact.m1m2.height
supply_offset = vector(position.x + contact_correct, self.gnd_position.y)
self.add_contact_center(layers=("metal1", "via1", "metal2"),
offset=supply_offset,
rotate=90)