Add the custom DFF RAM
diff --git a/openlane/DFFRAM/pdn.tcl b/openlane/DFFRAM/pdn.tcl
new file mode 100644
index 0000000..947bd06
--- /dev/null
+++ b/openlane/DFFRAM/pdn.tcl
@@ -0,0 +1,27 @@
+# Power nets
+set ::power_nets $::env(VDD_PIN)
+set ::ground_nets $::env(GND_PIN)
+
+
+pdngen::specify_grid stdcell {
+ name grid
+ rails {
+ met1 {width 0.48 pitch $::env(PLACE_SITE_HEIGHT) offset 0}
+ }
+ straps {
+ met4 {width 1.6 pitch $::env(FP_PDN_VPITCH) offset $::env(FP_PDN_VOFFSET)}
+ }
+ connect {{met1 met4}}
+}
+
+
+set ::halo 0
+
+# Metal layer for rails on every row
+set ::rails_mlayer "met1" ;
+
+# POWER or GROUND #Std. cell rails starting with power or ground rails at the bottom of the core area
+set ::rails_start_with "POWER" ;
+
+# POWER or GROUND #Upper metal stripes starting with power or ground rails at the left/bottom of the core area
+set ::stripes_start_with "POWER" ;
