diff --git a/xschem/cfg_shift_register.sch b/xschem/cfg_shift_register.sch
index eccb4a3..e074680 100644
--- a/xschem/cfg_shift_register.sch
+++ b/xschem/cfg_shift_register.sch
@@ -45,22 +45,30 @@
 N 1300 -70 1300 -40 { lab=q[5]}
 N 1500 -70 1500 -40 { lab=q[6]}
 N 1700 -70 1700 -40 { lab=q[7]}
+N 310 -30 1720 -30 { lab=xxx}
 C {sky130/sky130_stdcells/dfxtp_1.sym} 190 -80 0 0 {name=x1 VGND=GND VNB=GND VPB=VDD VPWR=VDD prefix=sky130_fd_sc_hd__ }
 C {devices/ipin.sym} 70 -120 0 0 {name=p1 lab=clk}
-C {devices/opin.sym} 300 -40 1 0 {name=p3 lab=q[0]}
-C {devices/opin.sym} 500 -40 1 0 {name=p4 lab=q[1]
+C {devices/bus_connect.sym} 310 -30 0 1 {name=l3 lab=q[0]}
+C {devices/bus_connect.sym} 510 -30 0 1 {name=l4 lab=q[1]
 }
-C {devices/opin.sym} 700 -40 1 0 {name=p5 lab=q[2]
+C {devices/bus_connect.sym} 710 -30 0 1 {name=l1 lab=q[2]
+
 }
-C {devices/opin.sym} 900 -40 1 0 {name=p6 lab=q[3]
+C {devices/bus_connect.sym} 910 -30 0 1 {name=l2 lab=q[3]
+
 }
-C {devices/opin.sym} 1100 -40 1 0 {name=p7 lab=q[4]
+C {devices/bus_connect.sym} 1110 -30 0 1 {name=l5 lab=q[4]
+
 }
-C {devices/opin.sym} 1300 -40 1 0 {name=p8 lab=q[5]
+C {devices/bus_connect.sym} 1310 -30 0 1 {name=l6 lab=q[5]
+
 }
-C {devices/opin.sym} 1500 -40 1 0 {name=p9 lab=q[6]
+C {devices/bus_connect.sym} 1510 -30 0 1 {name=l7 lab=q[6]
+
 }
-C {devices/opin.sym} 1700 -40 1 0 {name=p10 lab=q[7]}
+C {devices/bus_connect.sym} 1710 -30 0 1 {name=l8 lab=q[7]
+
+}
 C {devices/ipin.sym} 100 -40 3 0 {name=p2 lab=d_in}
 C {devices/code_shown.sym} 120 -210 0 0 {name=MODELS
 only_toplevel=true
@@ -77,3 +85,4 @@
 C {sky130/sky130_stdcells/dfxtp_1.sym} 1190 -80 0 0 {name=x6 VGND=GND VNB=GND VPB=VDD VPWR=VDD prefix=sky130_fd_sc_hd__ }
 C {sky130/sky130_stdcells/dfxtp_1.sym} 1390 -80 0 0 {name=x7 VGND=GND VNB=GND VPB=VDD VPWR=VDD prefix=sky130_fd_sc_hd__ }
 C {sky130/sky130_stdcells/dfxtp_1.sym} 1590 -80 0 0 {name=x8 VGND=GND VNB=GND VPB=VDD VPWR=VDD prefix=sky130_fd_sc_hd__ }
+C {devices/opin.sym} 1720 -30 0 0 {name=p3 lab=q[7:0]}
diff --git a/xschem/cfg_shift_register.sym b/xschem/cfg_shift_register.sym
new file mode 100644
index 0000000..ccf31b2
--- /dev/null
+++ b/xschem/cfg_shift_register.sym
@@ -0,0 +1,24 @@
+v {xschem version=3.0.0 file_version=1.2 }
+G {}
+K {type=subcircuit
+format="@name @@clk @@d_in @@q[7:0] @VDD @GND @symname"
+template="name=X1 VDD=VDD GND=GND"
+extra="VDD GND"}
+V {}
+S {}
+E {}
+L 4 560 -160 600 -160 {}
+L 4 60 -160 100 -160 {}
+L 4 60 -100 100 -100 {}
+B 5 57.5 -102.5 62.5 -97.5 {name=clk
+dir=in}
+B 5 57.5 -162.5 62.5 -157.5 {name=d_in
+dir=in}
+B 5 597.5 -162.5 602.5 -157.5 {name=q[7:0]
+dir=out}
+P 4 5 100 -200 560 -200 560 -80 100 -80 100 -200 {}
+T {CONFIG SREG} 180 -150 0 0 0.8 0.8 {}
+T {@name} 290 -220 0 0 0.3 0.3 {}
+T {clk} 100 -110 0 0 0.3 0.3 {}
+T {d_in} 100 -170 0 0 0.3 0.3 {}
+T {q[7:0]} 510 -170 0 0 0.3 0.3 {}
diff --git a/xschem/cfg_shift_register_tb.sch b/xschem/cfg_shift_register_tb.sch
new file mode 100644
index 0000000..4425a88
--- /dev/null
+++ b/xschem/cfg_shift_register_tb.sch
@@ -0,0 +1,56 @@
+v {xschem version=3.0.0 file_version=1.2 }
+G {}
+K {}
+V {}
+S {}
+E {}
+N 130 -180 170 -180 { lab=#net1}
+N 710 -180 760 -180 { lab=q[7:0]}
+N 30 -180 70 -180 { lab=d_d_in}
+N 30 -120 70 -120 { lab=d_clk}
+N 130 -120 170 -120 { lab=#net2}
+C {xschem/cfg_shift_register.sym} 110 -20 0 0 {name=x3 VDD=VDD GND=GND}
+C {devices/dac_bridge.sym} 100 -180 0 0 {name=A1 dac_bridge_model=dac_1v5}
+C {devices/code_shown.sym} 20 -60 0 0 {name=s1 only_toplevel=false 
+value=".model dac_1v5 dac_bridge(out_low=0.0 out_high=1.5 
++ out_undef=0.75 input_load=1e-12 t_rise=100e-12 t_fall=100e-12)"}
+C {devices/dac_bridge.sym} 100 -120 0 0 {name=A2 dac_bridge_model=dac_1v5}
+C {devices/lab_wire.sym} 760 -180 0 0 {name=l1 sig_type=std_logic lab=q[7:0]}
+C {devices/code.sym} 710 -120 0 0 {name=STIMULI 
+only_toplevel=true
+place=end
+value="
+* power voltage
+vvdd VDD 0 1.5
+
+** STATIC CONTOL
+
+
+** Signal
+a_source [d_clk d_d_in] d_source1
+.model d_source1 d_source(input_file=\\"cfg_sreg_din.txt\\")
+
+
+.control
+save all
+set temp=27
+
+* RUN SIMULATION
+tran 1n 20n
+
+* OUTPUT
+set hcopydevtype = svg
+hardcopy ./sreg_tb.svg  net1-2 net2-2 \\"q[0]\\" \\"q[1]\\"+2 \\"q[2]\\"+4 \\"q[3]\\"+6 \\"q[4]\\"+8 \\"q[5]\\"+10 \\"q[6]\\"+12 \\"q[7]\\"+14 title 'SSTL Test Circuit'
+
+.endc
+"}
+C {devices/code.sym} 850 -120 0 0 {name=MODELS
+only_toplevel=true
+format="tcleval( @value )"
+value="** Local library links to pdk
+.lib sky130/libs/tt_lib.spice tt
+.include \\\\$::SKYWATER_STDCELLS\\\\/sky130_fd_sc_hd.spice
+"
+spice_ignore=false}
+C {devices/lab_wire.sym} 70 -120 0 0 {name=l2 sig_type=std_logic lab=d_clk}
+C {devices/lab_wire.sym} 70 -180 0 0 {name=l3 sig_type=std_logic lab=d_d_in}
diff --git a/xschem/cfg_shift_register_tb.spice b/xschem/cfg_shift_register_tb.spice
new file mode 100644
index 0000000..9a2a4b2
--- /dev/null
+++ b/xschem/cfg_shift_register_tb.spice
@@ -0,0 +1,64 @@
+**.subckt cfg_shift_register_tb
+x3 net2 net1 q[7] q[6] q[5] q[4] q[3] q[2] q[1] q[0] VDD GND cfg_shift_register
+A1 [ d_d_in ] [ net1 ] dac_1v5
+A2 [ d_clk ] [ net2 ] dac_1v5
+**** begin user architecture code
+
+.model dac_1v5 dac_bridge(out_low=0.0 out_high=1.5   out_undef=0.75 input_load=1e-12 t_rise=100e-12
++ t_fall=100e-12)
+
+ ** Local library links to pdk
+.lib sky130/libs/tt_lib.spice tt
+.include /home/derekhm/proj/caravan-project/pdk/sky130A/libs.ref/sky130_fd_sc_hd/spice/sky130_fd_sc_hd.spice
+
+**** end user architecture code
+**.ends
+
+* expanding   symbol:  xschem/cfg_shift_register.sym # of pins=3
+* sym_path: /home/derekhm/proj/caravan-project/xschem/cfg_shift_register.sym
+* sch_path: /home/derekhm/proj/caravan-project/xschem/cfg_shift_register.sch
+.subckt cfg_shift_register  clk  d_in  q[7] q[6] q[5] q[4] q[3] q[2] q[1] q[0]  VDD  GND
+*.ipin clk
+*.ipin d_in
+*.opin q[7],q[6],q[5],q[4],q[3],q[2],q[1],q[0]
+x1 clk d_in GND GND VDD VDD q[0] sky130_fd_sc_hd__dfxtp_1
+x2 clk q[0] GND GND VDD VDD q[1] sky130_fd_sc_hd__dfxtp_1
+x3 clk q[1] GND GND VDD VDD q[2] sky130_fd_sc_hd__dfxtp_1
+x4 clk q[2] GND GND VDD VDD q[3] sky130_fd_sc_hd__dfxtp_1
+x5 clk q[3] GND GND VDD VDD q[4] sky130_fd_sc_hd__dfxtp_1
+x6 clk q[4] GND GND VDD VDD q[5] sky130_fd_sc_hd__dfxtp_1
+x7 clk q[5] GND GND VDD VDD q[6] sky130_fd_sc_hd__dfxtp_1
+x8 clk q[6] GND GND VDD VDD q[7] sky130_fd_sc_hd__dfxtp_1
+.ends
+
+**** begin user architecture code
+
+
+* power voltage
+vvdd VDD 0 1.5
+
+** STATIC CONTOL
+
+
+** Signal
+a_source [d_clk d_d_in] d_source1
+.model d_source1 d_source(input_file="cfg_sreg_din.txt")
+
+
+.control
+save all
+set temp=27
+
+* RUN SIMULATION
+tran 1n 20n
+
+* OUTPUT
+set hcopydevtype = svg
+hardcopy ./sreg_tb.svg  net1-2 net2-2 "q[0]" "q[1]"+2 "q[2]"+4 "q[3]"+6 "q[4]"+8 "q[5]"+10 "q[6]"+12
++ "q[7]"+14 title 'SSTL Test Circuit'
+
+.endc
+
+
+**** end user architecture code
+.end
diff --git a/xschem/cfg_sreg_din.txt b/xschem/cfg_sreg_din.txt
new file mode 100755
index 0000000..57cc849
--- /dev/null
+++ b/xschem/cfg_sreg_din.txt
@@ -0,0 +1,17 @@
+* time, d_clk d_d_in
+0n      0s 1s  
+1n      1s 1s
+2n      0s 0s
+3n      1s 0s
+4n      0s 1s
+5n      1s 1s
+6n      0s 0s
+7n      1s 0s
+8n      0s 1s
+9n      1s 1s
+10n     0s 0s
+11n     1s 0s
+12n     0s 1s
+13n     1s 1s
+14n     0s 0s
+15n     1s 0s
\ No newline at end of file
diff --git a/xschem/proj_sstl_test_tb.spice b/xschem/proj_sstl_test_tb.spice
index 0de2513..e3cb41b 100644
--- a/xschem/proj_sstl_test_tb.spice
+++ b/xschem/proj_sstl_test_tb.spice
@@ -9,12 +9,12 @@
 **** begin user architecture code
  ** Local library links to pdk
 .lib ./sky130/libs/tt_lib.spice tt
-.include /home/derekhm/cad/share/pdk/sky130A/libs.ref/sky130_fd_sc_hd/spice/sky130_fd_sc_hd.spice
+.include /home/derekhm/proj/caravan-project/pdk/sky130A/libs.ref/sky130_fd_sc_hd/spice/sky130_fd_sc_hd.spice
 
 **** end user architecture code
 **.ends
 
-* expanding   symbol:  /home/derekhm/proj/caravan-project/xschem/proj_sstl_test.sym # of pins=14
+* expanding   symbol:  xschem/proj_sstl_test.sym # of pins=14
 * sym_path: /home/derekhm/proj/caravan-project/xschem/proj_sstl_test.sym
 * sch_path: /home/derekhm/proj/caravan-project/xschem/proj_sstl_test.sch
 .subckt proj_sstl_test  rx_leg_ctrl[6] rx_leg_ctrl[5] rx_leg_ctrl[4] rx_leg_ctrl[3] rx_leg_ctrl[2]
@@ -69,7 +69,7 @@
 .ends
 
 
-* expanding   symbol:  /home/derekhm/proj/caravan-project/xschem/SSTL/SSTL.sym # of pins=5
+* expanding   symbol:  xschem/SSTL/SSTL.sym # of pins=5
 * sym_path: /home/derekhm/proj/caravan-project/xschem/SSTL/SSTL.sym
 * sch_path: /home/derekhm/proj/caravan-project/xschem/SSTL/SSTL.sch
 .subckt SSTL  DQ  pd_ctrl[6] pd_ctrl[5] pd_ctrl[4] pd_ctrl[3] pd_ctrl[2] pd_ctrl[1] pd_ctrl[0]