###############################################
## Logs serial data from the USB Bit Whacker
## Scott Hendrickson
## Aug 28, 2007
###############################################

from serial import *

# This program relies on:
# Python Serial Port Extension for Win32, Linux, BSD, Jython
#	serial driver for win32
# by Chris Liechti <cliechti@gmx.net>
# (Distributed with Enthought Python)

import sys, time, csv

def command(c):
	buf = ''
	tty.write(c)
	while (tty.inWaiting() > 0):
		buf = tty.read(tty.inWaiting())
	return buf
		
def volts(x):
	return x*5./1024.


## Main
# Initialize the serial port
tty = Serial('COM6',9600,timeout=0)
tty.databits = 8
tty.open()
print tty
    
print "Please initialize the UBW-PIC device. Press return when ready...\n"
wait = sys.stdin.readline()

print 'USB Port Volt Meter V1.0 (2007-08-26)'

## UBW Firmware D V1.3 is the data acquisition device
# prints the version
print command('V\r') + '\n'
# set A = 11000000 B = 0, C = 255 inputs and analog count to 2 (an0, an1)
command('C,3,0,255,2\r')
# Tell the UBW to send an analog reading every 80 ms
command('T,80,1\r')
# open the output file
writer = csv.writer(open('volt_results.csv','wb'))

reading = []
count = 0
# Start logging set this to the number of intervals to record
# (500*80 ms = 40 sec)
while (count<500):
	while (tty.inWaiting() > 0):
		buf = tty.read(tty.inWaiting())
		reading = buf.split(',')
	if len(reading) > 1:
		v1 = volts(int(reading[1].strip('\n\r')))
		v2 = volts(int(reading[2].strip('\n\r')))
		# print readings to screen
		sys.stdout.write('\r (%.2f, %.2f) Volts' % (v1,v2))
		# log voltage readings
		writer.writerow([time.clock(),v1,v2])
		count += 1
		reading = []

print '\nDone.'