Wrapper around uChameleon2 and histogram of ADC readings

chameleon-wrapper.py

from __future__ import division
import serial
import numpy as np
import pylab as plt

from __future__ import division
import serial
import numpy as np
import pylab as plt

class Chameleon:
    def __init__(self,portName):
        self.connection = serial.Serial(portName,timeout=1)
        self.connection.write("id\n")
        self.id = self.connection.readline()
        print self.id
        self.connection.write("led pattern 5\n")    # Change led pattern to indicate communication on
        
    def read(self,n):
        self.connection.write("adc "+`n`+" v\n")
        return float( (1+int(self.connection.readline()[-5:-1].strip(' ')))/4096 ) 
    
    def pwmStart(self,n):
        self.connection.write("pwm "+`n`+" on\n")

    def pwmStop(self,n):
        self.connection.write("pwm "+`n`+" off\n")        

    def pwmPeriod(self,n,p):
        # Clock is at 24 MHz. Each period is 41.6 ns.
        self.connection.write("pwm "+`n`+" period "+`p`+"\n")        

    def pwmWidth(self,n,w):
        self.connection.write("pwm "+`n`+" width "+`w`+"\n")        
    
    def pwmOut(self,n,V,p=1000):
        w = int(p * V/5.) 
        self.pwmPeriod(n,p)
        self.pwmWidth(n,w)
        
    def close(self):
        self.connection.write("led pattern 2\n")
        self.connection.close()
        
# Acquire 2000 voltage readings from channel 5        
c = Chameleon('COM7')
V = []
for i in range(2000): V.append(c.read(5))
c.close()


# Plot histogram of acquired voltage values
fig = plt.figure()
ax = fig.add_subplot(111)
n, bins, patches = ax.hist(V, bins=50, histtype='bar')

ax.set_xlabel("Voltage [V]")
ax.set_ylabel("Frequency")