"""
-------------------------------------------------------------------------------------------
	(C)2008 Nuria Pujol Vilanova <nuriapujolvilanova@gmail.com>	
	
	FILE NAME: OOS4000.py

	DESCRIPTION:
		USB comunication module for USB4000 Device (Ocean Optics) in Python.
				
				- OpenDevice
				- ResetDevice
				- SentIntTime
				- GetSample
				- MaxSample
				- GetReducedSample
				
	OS4000.py file improvement according new scenario (S4000AppPc.py)
	
	GPL License
-------------------------------------------------------------------------------------------
"""
import sys, os,usb
from struct import pack,unpack
from numpy import*
from time import time
from pylab import plot,show

def OpenDevice(id=0x2457): #id=Hex identificator
	"""
	-----------------------------------------------------------------------------------------
	OpenDevice(id=0x2457)

	DESCRIPTION:

	Return a HandleDevice varible related with a USB device that has the same 
	'id' identifier.
	(HandleDevice Object is the only able to write and read in USB comunication)
			
	ARGUMENTS:		
	
	id -- hexadecimal idVendor identifier (default =0x2457) 
	-----------------------------------------------------------------------------------------	
	"""
	buses = usb.busses()
	for bus in buses :
		for device in bus.devices :
			if device.idVendor == id:
				print "USB4000 Device Found"

				dev=device
			elif device.idVendor==0:
				pass
			else:
				print "Other type of Device Found"
				
	handle= dev.open()
	return handle

def ResetDevice(handle):#handle device
	""" 
	-----------------------------------------------------------------------------------------
	ResetDevice(handle)

	DESCRIPTION:

	Reset the comunication. Non output.

	ARGUMENTS:	
			
	handle -- HandleDavice Object related to comunication to reset. 
	Object returned by OpenDevice
	-----------------------------------------------------------------------------------------
	"""
	
	handle.reset()
	
def SetIntTime(handle,buf_tx):
	"""
	-----------------------------------------------------------------------------------------
	SetIntTime(handle,buf_tx)
	
	DESCRIPTION:

	Write new integration time value on the device. Non output.

	ARGUMENTS:		
			
	handle -- HandleDavice Object related to device to set new integration time. 
	Object returned by OpenDevice
	
	buf_tx --  New integration time in vendor descrived format.
	
	*buf_tx= chr(0x02) + struct.pack('i', IntegrationTimeValue)
	buf_tx obtained from S4000AppPc.py execution
	
	-----------------------------------------------------------------------------------------
	"""
	o=handle.bulkWrite(0x01,buf_tx)

def GetSample(buf_tx,itime,id=0x2457):
	
	"""
	-----------------------------------------------------------------------------------------
	GetSample(buf_tx,itime,id=0x257)
	
	DESCRIPTION:

	Return a single adquisition in a vector (3840 values)

	ARGUMENTS:		
	
	buf_tx -- New integration time in vendor descrived format.
	itime -- Integration time in INT format
	id -- Hexadecimal idVendor identifier (default =0x2457) 

	*buf_tx= chr(0x02) + struct.pack('i', IntegrationTimeValue)
	buf_tx obtained from S4000AppPc.py execution
	
	------------------------------------------------------------------------------------------
	"""
	#----------------------------------------------------------------------------------------
	#-- 'itime' is only used to calculate time that USB buffer have
	#-- to wait.
	#-- Provably, only 'buf_tx' will be enough, buf_tx can be easully 
	#-- translated to itime (to improve)*
	#----------------------------------------------------------------------------------------

	handle=OpenDevice(id)
	#ResetDevice(handle)
	SetIntTime(handle,buf_tx)

	buffer=chr(0x09)
	o=handle.bulkWrite(0x01,buffer)

	SampleTime=int(time()) 
	
	#-----------------------------------------------------------------------------------------
	#-- 'sampletime' is when sample is 'taken' in seconds (UTC format)
	#-- more or less to be stored in netCDFFile if is necessary
	#-----------------------------------------------------------------------------------------
	
	b0=handle.bulkRead(0x86,2048,itime/7)
	b4=handle.bulkRead(0x82,5632,itime/11)
	sincro=handle.bulkRead(0x82,1)
	#'sincro' not util data but has to be readed, if not it remains in buffer
	
	data=b0+b4
	#'data' is util data readed from USB4000
	
	#----------------------------------------------------------------------------------------
	#-- Every spectrometric data (for every photodiode) has 2 bytes and
	#-- become from USB4000 in this format:
	#--
	#-- [LSB photodiode1,MSB phot1,LSB phot2,MSB phot2,...]
	#--
	#-- 'SpecSignature' contain LSB and MSB combined getting values
	#-- from '0' (ideally, always there is some noise) to 32000 that can be
	#-- represented graphically
	#----------------------------------------------------------------------------------------
	
	data=[x for x in data]
	
	dataLSB=[((256+data[2*i])&0xFF) for i in range(len(data)/2)]
	dataMSB=[((256+data[2*i+1])&0xFF)<<8 for i in range(len(data)/2)]

	SpecSignature=[dataLSB[i]^dataMSB[i] for i in range(len(dataLSB))]
	
	return SpecSignature,SampleTime

	#----------------------------------------------------------------------------------------
	#--'SpecSignature can be represented on Pc screen but not in PDA
	#-- (there are more points (values) than screen pixels.
	#-- For this reasons we have to decrease the numer of SpecSignature
	#-- values (we loose resolution) but we can still recognize signal 
	#-- obteined.
	#-- Entire SpecSignature will be saved on a database in netCDF format 
	#-- (if this option is selected on PDA) and this reduced sample sent
	#-- to PDA to be represented
	#----------------------------------------------------------------------------------------

def MaxSample(SpecSignature):
	"""
	-----------------------------------------------------------------------------------------
	MaxSample(SpecSignature)
	
	DESCRIPTION:

	Return maximum value of a sample

	ARGUMENTS:		
	
	SpecSignature -- One single sample values vector
	
	----
	"""
	length =len(SpecSignature)
	maximum=max(SpecSignature[2:length]) 
	
	return maximum
		
def GetReducedSample(SpecSignature,screenV=120,screenH=240):
	"""
	-----------------------------------------------------------------------------------------
	GetReducedSample(SpecSignature,screenV=100,screenH=240)
	
	DESCRIPTION:

	From entire sample obteined from USB4000 (SpecSignature) obtain a 
	'reduced'  sample able to be 'drawn' on PDA screen size

	ARGUMENTS:		
	
	SpecSignature -- One single sample values vector
	screenV -- number of able PDA screen pixels on vertical
	screenH -- number of able PDA screen pixels on horizontal
	----
	"""
	resolution=int(len(SpecSignature)/screenH)
	short_signature=[]
	maximum=MaxSample(SpecSignature)
	
	for x in range(screenH):
		short_signature.append(screenV-((SpecSignature[x*resolution]*screenV)/maximum)) 
		#----------------------------------------------------------------------------------------
		#-- Samples values ajustements according to screen size
		#-- (screenH x screenV in pixels)
		#----------------------------------------------------------------------------------------

	return short_signature

def main():
	itime=300000
	buf_tx=chr(0x02)+pack('i',itime)
	[lectura,time]=GetSample(buf_tx,itime)
	
	plot(lectura)
	show()
	
if __name__ == '__main__':
	main()