examples: add basic DDS frequency setter with dynamic DDB scan

examples/master/repository/dds_setter.py

@@ -0,0 +1,25 @@
+from operator import itemgetter
+
+from artiq import *
+
+
+class DDSSetter(EnvExperiment):
+    """DDS Setter"""
+    def build(self):
+        self.dds = dict()
+
+        ddb = self.get_ddb()
+        for k, v in sorted(ddb.items(), key=itemgetter(0)):
+            if (isinstance(v, dict)
+                    and v["type"] == "local"
+                    and v["module"] == "artiq.coredevice.dds"
+                    and v["class"] in {"AD9858", "AD9914"}):
+                self.dds[k] = {
+                    "driver": self.get_device(k),
+                    "frequency": self.get_argument("{}_frequency".format(k),
+                                                   NumberValue())
+                }
+
+    def run(self):
+        for k, v in self.dds.items():
+            v["driver"].set(v["frequency"])