# HG changeset patch
# User Daniel O'Connor <doconnor@gsoft.com.au>
# Date 1610077224 -37800
# Node ID 4ca9fdf0795ac6679bbd1db0b90abda6dc6741f8
# Parent  c90db15a497ece701c1c779dbaba3542f7d0b9b1
Add simple scope example

diff -r c90db15a497e -r 4ca9fdf0795a example.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/example.py	Fri Jan 08 14:10:24 2021 +1030
@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2009
+#      Daniel O'Connor <darius@dons.net.au>.  All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+import usb488
+import matplotlib.pylab as pylab
+import numpy
+import time
+
+def main():
+    u = usb488.USB488Device()
+    print("Found device")
+
+    u.write("*IDN?")
+    print("IDN reports " + u.read())
+    
+    u.write("DATA:ENC RIB")	# Big endian signed
+    u.write("DATA:WIDTH 2")	# 2 bytes wide
+    u.write("SELECT:CH1 ON")	# Turn channel 1 on
+    u.write("DATA:SOURCE CH1")	# Set the curve source to channel 1
+
+    u.write("CH1:SCALE?")
+    vscale = float(u.read(1).split()[1])
+    print("Channel 1 scale is %.2f volts/div" % (vscale))
+    u.write("HOR:MAIN:SCALE?")
+    hscale = float(u.read(1).split()[1])
+    print("Horizontal scale is %f sec/div" % (hscale))
+
+    u.write("*WAI")		# Make sure the previous commands have been
+                                # executed
+    u.write("CURVE?")		# Ask for the curve data
+    then = time.time()                            
+    result = u.read(1.0)	# Takes the CRO a while for this
+    now = time.time()
+    print("CURVE read took %f milliseconds" % ((now - then) * 1000.0))
+    data = result[13:]		# Chop off the header (should verify this really..)
+    dattype = numpy.dtype('>h')	# Big endian 16 bit quantity
+    ary = numpy.fromstring(data, dtype = dattype)
+    ary = ary / 32768.0 * vscale
+    pylab.plot(ary)
+    pylab.show()
+    
+if __name__ == "__main__":
+    main()