m-labs · Sep 5, 2015 · Sep 5, 2015 · Sep 5, 2015
Showing with 59 additions and 20 deletions.

+20 −5 artiq/coredevice/dds.py

+1 −1 artiq/coredevice/runtime.py

+11 −5 artiq/language/scan.py

+26 −8 soc/runtime/dds.c

+1 −1 soc/runtime/dds.h
diff --git a/artiq/coredevice/dds.py b/artiq/coredevice/dds.py
@@ -89,6 +89,17 @@ def pow_to_turns(self, pow):
         word."""
         return pow/2**self.pow_width
 
+    @portable
+    def amplitude_to_asf(self, amplitude):
+        """Returns amplitude scale factor corresponding to given amplitude."""
+        return round(amplitude*0x0fff)
+
+    @portable
+    def asf_to_amplitude(self, asf):
+        """Returns the amplitude corresponding to the given amplitude scale
+           factor."""
+        return round(amplitude*0x0fff)
+
     @kernel
     def init(self):
         """Resets and initializes the DDS channel.
@@ -117,12 +128,14 @@ def set_phase_mode(self, phase_mode):
         self.phase_mode = phase_mode
 
     @kernel
-    def set_mu(self, frequency, phase=0, phase_mode=_PHASE_MODE_DEFAULT):
+    def set_mu(self, frequency, phase=0, phase_mode=_PHASE_MODE_DEFAULT,
+               amplitude=0x0fff):
         """Sets the DDS channel to the specified frequency and phase.
 
         This uses machine units (FTW and POW). The frequency tuning word width
         is 32, whereas the phase offset word width depends on the type of DDS
-        chip and can be retrieved via the ``pow_width`` attribute.
+        chip and can be retrieved via the ``pow_width`` attribute. The amplitude
+        width is 12.
 
         :param frequency: frequency to generate.
         :param phase: adds an offset, in turns, to the phase.
@@ -132,13 +145,15 @@ def set_mu(self, frequency, phase=0, phase_mode=_PHASE_MODE_DEFAULT):
         if phase_mode == _PHASE_MODE_DEFAULT:
             phase_mode = self.phase_mode
         syscall("dds_set", now_mu(), self.channel, frequency,
-                phase, phase_mode)
+                phase, phase_mode, amplitude)
 
     @kernel
-    def set(self, frequency, phase=0.0, phase_mode=_PHASE_MODE_DEFAULT):
+    def set(self, frequency, phase=0.0, phase_mode=_PHASE_MODE_DEFAULT,
+            amplitude=1.0):
         """Like ``set_mu``, but uses Hz and turns."""
         self.set_mu(self.frequency_to_ftw(frequency),
-                    self.turns_to_pow(phase), phase_mode)
+                    self.turns_to_pow(phase), phase_mode,
+                    self.amplitude_to_asf(amplitude))
 
 
 class AD9858(_DDSGeneric):

diff --git a/artiq/coredevice/runtime.py b/artiq/coredevice/runtime.py
@@ -25,7 +25,7 @@
     "dds_init": "Ii:n",
     "dds_batch_enter": "I:n",
     "dds_batch_exit": "n:n",
-    "dds_set": "Iiiii:n",
+    "dds_set": "Iiiiii:n",
 }
 
 

diff --git a/artiq/language/scan.py b/artiq/language/scan.py
@@ -25,10 +25,16 @@
 from artiq.language.environment import NoDefault, DefaultMissing
 
 
-__all__ = ["NoScan", "LinearScan", "RandomScan", "ExplicitScan", "Scannable"]
+__all__ = ["ScanObject",
+           "NoScan", "LinearScan", "RandomScan", "ExplicitScan",
+           "Scannable"]
 
 
-class NoScan:
+class ScanObject:
+    pass
+
+
+class NoScan(ScanObject):
     """A scan object that yields a single value."""
     def __init__(self, value):
         self.value = value
@@ -45,7 +51,7 @@ def describe(self):
         return {"ty": "NoScan", "value": self.value}
 
 
-class LinearScan:
+class LinearScan(ScanObject):
     """A scan object that yields a fixed number of increasing evenly
     spaced values in a range."""
     def __init__(self, min, max, npoints):
@@ -69,7 +75,7 @@ def describe(self):
                 "min": self.min, "max": self.max, "npoints": self.npoints}
 
 
-class RandomScan:
+class RandomScan(ScanObject):
     """A scan object that yields a fixed number of randomly ordered evenly
     spaced values in a range."""
     def __init__(self, min, max, npoints, seed=0):
@@ -85,7 +91,7 @@ def describe(self):
                 "min": self.min, "max": self.max, "npoints": self.npoints}
 
 
-class ExplicitScan:
+class ExplicitScan(ScanObject):
     """A scan object that yields values from an explicitly defined sequence."""
     def __init__(self, sequence):
         self.sequence = sequence

diff --git a/soc/runtime/dds.c b/soc/runtime/dds.c
@@ -18,8 +18,8 @@
 /* DAC calibration takes max. 1ms as per datasheet */
 #define DURATION_DAC_CAL (147000 << RTIO_FINE_TS_WIDTH)
 /* not counting final FUD */
-#define DURATION_INIT (10*DURATION_WRITE + DURATION_DAC_CAL)
-#define DURATION_PROGRAM (5*DURATION_WRITE) /* not counting FUD */
+#define DURATION_INIT (8*DURATION_WRITE + DURATION_DAC_CAL)
+#define DURATION_PROGRAM (6*DURATION_WRITE) /* not counting FUD */
 
 #else
 #error Unknown DDS configuration
@@ -59,8 +59,17 @@ void dds_init(long long int timestamp, int channel)
 #endif
     channel <<= 1;
     DDS_WRITE(DDS_GPIO, channel);
+#ifndef DDS_AD9914
+    /*
+     * Resetting a AD9914 intermittently crashes it. It does not produce any
+     * output until power-cycled.
+     * Increasing the reset pulse length and the delay until the first write
+     * to 300ns do not solve the problem.
+     * The chips seem fine without a reset.
+     */
     DDS_WRITE(DDS_GPIO, channel | 1); /* reset */
     DDS_WRITE(DDS_GPIO, channel);
+#endif
 
 #ifdef DDS_AD9858
     /*
@@ -94,7 +103,7 @@ void dds_init(long long int timestamp, int channel)
 static unsigned int continuous_phase_comp[DDS_CHANNEL_COUNT];
 
 static void dds_set_one(long long int now, long long int ref_time, unsigned int channel,
-    unsigned int ftw, unsigned int pow, int phase_mode)
+    unsigned int ftw, unsigned int pow, int phase_mode, unsigned int amplitude)
 {
     unsigned int channel_enc;
 
@@ -130,7 +139,8 @@ static void dds_set_one(long long int now, long long int ref_time, unsigned int
         DDS_WRITE(DDS_CFR2, 0x00);
 #endif
 #ifdef DDS_AD9914
-        DDS_WRITE(DDS_CFR1L, 0x0008);
+        /* Disable autoclear phase accumulator and enables OSK. */
+        DDS_WRITE(DDS_CFR1L, 0x0108);
 #endif
         pow += continuous_phase_comp[channel];
     } else {
@@ -141,7 +151,8 @@ static void dds_set_one(long long int now, long long int ref_time, unsigned int
         DDS_WRITE(DDS_CFR2, 0x40);
 #endif
 #ifdef DDS_AD9914
-        DDS_WRITE(DDS_CFR1L, 0x2008);
+        /* Enable autoclear phase accumulator and enables OSK. */
+        DDS_WRITE(DDS_CFR1L, 0x2108);
 #endif
         fud_time = now + 2*DURATION_WRITE;
         pow -= (ref_time - fud_time)*DDS_RTIO_CLK_RATIO*ftw >> (32-DDS_POW_WIDTH);
@@ -156,6 +167,9 @@ static void dds_set_one(long long int now, long long int ref_time, unsigned int
 #endif
 #ifdef DDS_AD9914
     DDS_WRITE(DDS_POW, pow);
+#endif
+#ifdef DDS_AD9914
+    DDS_WRITE(DDS_ASF, amplitude);
 #endif
     DDS_WRITE(DDS_FUD, 0);
 }
@@ -165,6 +179,7 @@ struct dds_set_params {
     unsigned int ftw;
     unsigned int pow;
     int phase_mode;
+    unsigned int amplitude;
 };
 
 static int batch_mode;
@@ -193,14 +208,15 @@ void dds_batch_exit(void)
     now = batch_ref_time - batch_count*(DURATION_PROGRAM + DURATION_WRITE);
     for(i=0;i<batch_count;i++) {
         dds_set_one(now, batch_ref_time,
-            batch[i].channel, batch[i].ftw, batch[i].pow, batch[i].phase_mode);
+            batch[i].channel, batch[i].ftw, batch[i].pow, batch[i].phase_mode,
+            batch[i].amplitude);
         now += DURATION_PROGRAM + DURATION_WRITE;
     }
     batch_mode = 0;
 }
 
 void dds_set(long long int timestamp, int channel,
-    unsigned int ftw, unsigned int pow, int phase_mode)
+    unsigned int ftw, unsigned int pow, int phase_mode, unsigned int amplitude)
 {
     if(batch_mode) {
         if(batch_count >= DDS_MAX_BATCH)
@@ -210,9 +226,11 @@ void dds_set(long long int timestamp, int channel,
         batch[batch_count].ftw = ftw;
         batch[batch_count].pow = pow;
         batch[batch_count].phase_mode = phase_mode;
+        batch[batch_count].amplitude = amplitude;
         batch_count++;
     } else {
         rtio_chan_sel_write(RTIO_DDS_CHANNEL);
-        dds_set_one(timestamp - DURATION_PROGRAM, timestamp, channel, ftw, pow, phase_mode);
+        dds_set_one(timestamp - DURATION_PROGRAM, timestamp, channel, ftw, pow, phase_mode,
+                    amplitude);
     }
 }
diff --git a/soc/runtime/dds.h b/soc/runtime/dds.h
@@ -59,6 +59,6 @@ void dds_init(long long int timestamp, int channel);
 void dds_batch_enter(long long int timestamp);
 void dds_batch_exit(void);
 void dds_set(long long int timestamp, int channel,
-    unsigned int ftw, unsigned int pow, int phase_mode);
+    unsigned int ftw, unsigned int pow, int phase_mode, unsigned int amplitude);
 
 #endif /* __DDS_H */