module: ezusb

file: http://darcs.erazor-zone.de/python/ezusb/ezusb.py

"""
  EZUSB Object
    copyright	Alexander Krause <alexander.krause@erazor-zone.de>
    date	2006.06.06
    version     0.0.1
"""
import usb
from ihex import ihex
 
class DeviceNotFound(Exception):
  def __init__(self,value):
    self.value=value
  def __str__(self):
    return repr(self.value)
 
class EZUSB:
  "EZUSB device class, to manage EZUSB via libusb"
  def __init__(self,vendorid,productid):
    self.device=self.findDevice(vendorid,productid)
    self.vendorid=vendorid
    self.productid=productid
 
  def findDevice(self,vendorid,productid):
    "get the first device on any bus with the given vendorid and productid."
    for bus in usb.busses():
      for device in bus.devices:
        if (device.idVendor==vendorid) and (device.idProduct==productid):
	  return device
    raise DeviceNotFound,'no device found'
 
  def writeRAM(self,addr,buffer):
    "write values directly into ram at address addr via endpoint-zero calls."
 
    self.device.open().controlMsg(0x40,0xa0,buffer,addr,0x00,1000)
 
  def reset(self,state=3):
    if state==3:
      self.writeRAM(0x7f92,[state&0x01])
    else:
      self.writeRAM(0x7f92,[1])
      self.writeRAM(0x7f92,[0])
 
  def downloadFW(self,filename):
    self.reset(1)
    newFW=ihex(filename)
    for mrecord in newFW.mrecords:
      self.writeRAM(mrecord.address,mrecord.data)
    self.reset(0)