##
# Python script to read samples from VSV board.
#
# USE: ./getaccdata.py | tee output.txt

import time
import serial
import sys

# Set serial port for your PC
serialport = '/dev/tty.usbserial-A4001lcR'

# Configure pySerial serial port.  Official documentation can be found here:
#  http://pyserial.sourceforge.net/
ser = serial.Serial(serialport, 115200, timeout=1)

sys.stderr.write('Delaying 4 seconds to allow Arduino to boot...')

# Delay 4 seconds to allow Arduino to 'boot-up'
#  (newer Decimilia-type Arduino's only)
time.sleep(4)

sys.stderr.write('  Done.\n')

# Turn on 'PC' light on VSV board
ser.write('v')

while 1:
    # Send 'read' command
    ser.write('r')

    # Read in 1024 samples
    for i in range(1024):

        # Read in upper/lower byte
        input_h = ser.read()
        input_l = ser.read()

        # Python reads serial data as strings; the following
        # two lines convert the upper and lower byte to ints
        sample_h = int(hex(ord(input_h)), 16)
        sample_l = int(hex(ord(input_l)), 16)

        # Convert two's complement data to a signed int
        if (sample_h > 127):
            sample_h = sample_h-255

        # Sample = (UpperByte << 8) + LowerByte 
        sample = sample_h * 256 + sample_l

        print str(sample)