re-check dac-adc direct connection, good

diff --git a/python-lib/mpsse-test.py b/python-lib/mpsse-test.py
index 7a980cbcfa0c90158a19f0284f7055f5f0c63f2f..d44950640b755c17c537050a9ce6910ad0971a7e 100755 (executable)
--- a/python-lib/mpsse-test.py
+++ b/python-lib/mpsse-test.py
@@ -136,6 +136,7 @@ dac.vbias_core(100e-3)
 dac.vbias_buf(100e-3)
 
 # zero others
+# part A already POR's to 0 but...
 for i in range(5, 8):
     dac.setv(i, 0.0)
 
@@ -234,6 +235,7 @@ adc.average(16, True)
 adc.convst_spi(1)
 
 # dac.vina --> adc.ch4
+# J604 -- J210
 adc.mux(4)
 
 #ch4 setup
@@ -248,17 +250,19 @@ if 0:
 
     n = []
     r = []
-    for i in range(2**10):
-        x = 2**6 * i
+    nbits = 16
+    for i in range(2**nbits):
+        x = 2**(16-nbits) * i
         dac.set(0, x)
         adc.read() #sham to trigger conversion
-        sleep(200e-6) #ensure 160us conversion time delay
+        sleep(160e-6) #ensure 160us conversion time delay
         n.append(x)
         v = adc.read()
         r.append(v)
-        print x, v
+        if i % 256 == 0:
+            print x, v
 
-    if 0:
+    if 1:
         figure()
         plot(n, r)
         xlabel('DAC code')

diff --git a/python-lib/usbio.py b/python-lib/usbio.py
index 1424c5a7f70ff7ef38b783c4adf966549e8533ab..f39af29c4600a946fceac489f9c1614e5f459e06 100644 (file)
--- a/python-lib/usbio.py
+++ b/python-lib/usbio.py
@@ -760,7 +760,8 @@ class AD524x(object):
 class DAC8568(object):
     CTL_WIDTH = 32
     DAC_WIDTH = 16
-    POR_VALUE = 2**(DAC_WIDTH - 1)
+    #POR_VALUE = 2**(DAC_WIDTH - 1)
+    POR_VALUE = 0
 
     ALL_CHANNELS = 0xf
 
@@ -1343,15 +1344,16 @@ class DigiReg(AD524x):
 class DAC_atoi(DAC8568):
     """Specific configuration and calibration for devboard DAC."""
     VREF = 2.5
-    GAIN = 2.0 #part options C/D
-    #POR_VALUE = 0 #part C
-    POR_VALUE = DAC8568.DAC_WIDTH / 2 #part D
+    GAIN = 1.0 #part options A/B
+    #GAIN = 2.0 #part options C/D
+    POR_VALUE = 0 #part A/C
+    #POR_VALUE = DAC8568.DAC_WIDTH / 2 #part B/D
 
     #zero-code output voltages
     VOS = ( 0.0,
             0.0,
             0.0,
-            5e-3,
+            0.0,
             0.0,
             0.0,
             0.0,