m-labs · Oct 14, 2014 · Oct 14, 2014
Showing with 47 additions and 1 deletion.

+10 −0 artiq/devices/rtio_core.py

+36 −0 examples/rtio_skew.py

+1 −1 soc/runtime/rtio.c
diff --git a/artiq/devices/rtio_core.py b/artiq/devices/rtio_core.py
@@ -137,3 +137,13 @@ def count(self):
         while syscall("rtio_get", self.channel) >= 0:
             count += 1
         return count
+
+    @kernel
+    def timestamp(self):
+        """Poll the RTIO input and returns an event timestamp, according to
+        the gating.
+
+        If the gate is permanently closed, returns a negative value.
+
+        """
+        return cycles_to_time(syscall("rtio_get", self.channel))
diff --git a/examples/rtio_skew.py b/examples/rtio_skew.py
@@ -0,0 +1,36 @@
+from artiq import *
+from artiq.devices import corecom_serial, core, rtio_core
+
+
+def print_skew(p):
+    print("Input/output skew: {} ns".format(p))
+
+
+def print_failed():
+    print("Pulse was not received back")
+
+
+class RTIOSkew(AutoContext):
+    parameters = "i o"
+
+    @kernel
+    def run(self):
+        with parallel:
+            self.i.gate_rising(10*us)
+            with sequential:
+                delay(5*us)
+                out_t = now()
+                self.o.pulse(5*us)
+        in_t = self.i.timestamp()
+        if in_t < 0*s:
+            print_failed()
+        else:
+            print_skew(int((out_t - in_t)/(1*ns)))
+
+if __name__ == "__main__":
+    with corecom_serial.CoreCom() as com:
+        coredev = core.Core(com)
+        exp = RTIOSkew(core=coredev,
+                       i=rtio_core.RTIOIn(core=coredev, channel=0),
+                       o=rtio_core.RTIOOut(core=coredev, channel=1))
+        exp.run()
diff --git a/soc/runtime/rtio.c b/soc/runtime/rtio.c
@@ -60,7 +60,7 @@ long long int rtio_get(int channel)
     rtio_chan_sel_write(channel);
     while(rtio_i_readable_read() || (rtio_o_level_read() != 0)) {
         if(rtio_i_readable_read()) {
-            r = rtio_i_value_read();
+            r = rtio_i_timestamp_read();
             rtio_i_re_write(1);
             return r;
         }