examples: Revise cont dig port output examples (#902)

* examples: Revise cont dig port output examples

* examples: Fix import order

Author: bkeryan

examples/digital_out/cont_gen_dig_port_int_clk.py

@@ -8,10 +8,16 @@
 from nidaqmx.constants import AcquisitionType, LineGrouping
 
 with nidaqmx.Task() as task:
-    data = [1, 2, 4, 8, 16, 32, 64, 128]
-
-    task.do_channels.add_do_chan("Dev1/port0", line_grouping=LineGrouping.CHAN_FOR_ALL_LINES)
+    chan = task.do_channels.add_do_chan("Dev1/port0", line_grouping=LineGrouping.CHAN_FOR_ALL_LINES)
     task.timing.cfg_samp_clk_timing(10.0, sample_mode=AcquisitionType.CONTINUOUS)
+
+    # Generate a walking 1's pattern.
+    data = [1 << i for i in range(chan.do_num_lines)]
+
+    print("Writing data:")
+    for i, value in enumerate(data):
+        print("sample {:2}: 0x{:0{width}X}".format(i, value, width=chan.do_num_lines // 4))
+
     task.write(data)
     task.start()
 

examples/digital_out/cont_gen_dig_port_int_clk_wfm.py

@@ -10,19 +10,18 @@
 import nidaqmx
 from nidaqmx.constants import AcquisitionType, LineGrouping
 
-np.set_printoptions(linewidth=220)  # ensure signal.data prints on a single line
+np.set_printoptions(linewidth=120)  # ensure signal.data prints on a single line
 
 with nidaqmx.Task() as task:
-    task.do_channels.add_do_chan("Dev1/port0", line_grouping=LineGrouping.CHAN_FOR_ALL_LINES)
+    chan = task.do_channels.add_do_chan("Dev1/port0", line_grouping=LineGrouping.CHAN_FOR_ALL_LINES)
     task.timing.cfg_samp_clk_timing(10.0, sample_mode=AcquisitionType.CONTINUOUS)
 
-    sample_count = 50
-    signal_count = task.do_channels[0].do_num_lines
-    waveform = DigitalWaveform(sample_count, signal_count)
-    for i in range(sample_count):
-        for j in range(signal_count):
-            waveform.signals[j].name = f"line {j:2}"
-            waveform.signals[j].data[i] = (i >> (j % 8)) & 1
+    # Generate a walking 1's pattern.
+    waveform = DigitalWaveform.from_port(
+        [1 << i for i in range(chan.do_num_lines)], mask=(1 << chan.do_num_lines) - 1
+    )
+    for signal in waveform.signals:
+        signal.name = f"line {signal.signal_index:2}"
 
     print("Writing data:")
     for signal in waveform.signals: