import logging
import threading
import time
from datetime import datetime
import u6
import traceback

# Event e signals between threads
e = threading.Event()

# Max number of requests to be read
MAX_REQUESTS = 1

# Initialize U6 and configure data stream
d = u6.U6()
d.getCalibrationData()
d.streamConfig( NumChannels = 1, ChannelNumbers = [0], ChannelOptions = [0],
                SettlingFactor = 1, ResolutionIndex = 1, ScanFrequency = 100 )

# Set DAC0 to 1.5V
DAC0_REG = 5000
d.writeRegister(DAC0_REG, 1.5)
time.sleep(1)

def wait_then_change_dac(e):
    # when event e is set, wait 500ms then change DAC value for 100ms
    e.wait()
    time.sleep(0.5)
    d.writeRegister(DAC0_REG, 3.5)
    print "------- Attempted to change DAC --------"
    time.sleep(0.1)
    d.writeRegister(DAC0_REG, 1.5) 

# Start data logging and try toggling DAC0
dac = threading.Thread(target=wait_then_change_dac, args=(e,))
dac.start()

try:
    d.streamStart()
    e.set()
    print "e is set"
    dataCount = 0
    for r in d.streamData():
        if r is not None:
            if dataCount >= MAX_REQUESTS:
                break
            if r['errors'] != 0:
                print "Errors"
            if r['numPackets'] != d.packetsPerRequest:
                print "Underflow"
            if r['missed'] != 0:
                print "Missed"

            for i in r['AIN0']:
                print i
            dataCount += 1
        else:
            print "No data"
except:
    print "".join(i for i in traceback.format_exc())
finally:
    d.streamStop()
    print "Stream stopped"
    d.close()