usb_test.py

#!/usr/bin/python

import os
import sys
import time

import usb.core
import usb.util



packet_len = 64

# Packing a request. Please see HexWax documentation for the list of all commands
# Packets are 64 bytes long, most of the commands are 4 bytes long. So up to 18
# can be batched into a packet. For example command with bytes [0x94, 0x0, 0x0, 0x0]
# is getting firmware id
def pack_request(*arguments):
    packet = [0x0] * packet_len
    i = 0
    for arg in arguments:
        packet[i] = arg
        i += 1
    #packet[0:4] = [0x94, 0x0, 0x0, 0x0] #get firmware id
    return ''.join([chr(c) for c in packet])

# Logs error to the error output
def log_error(functionName, ret):
    sys.stderr.write(functionName + (" failed with return code %d\n" % ret))

# Logs result onto standard output. Result is 64 bytes as decimal numbers
# Response is 64 bytes long
def show_result(bytes):
    sys.stdout.write("Result:")
    sys.stdout.write(''.join(['%d ' % abyte for abyte in bytes]))

# Turns LED on the bord on or off depending on input parameter on. 0 is turning
# the led on 1 is turning it off. The command is 0x9F set port bit (set output
# pin value), port is 0x03 (port C), 0x06 is bit index (so this is 7th bit),
# and the last bit is 0 for clear, 1 for set
def set_led(on, dev):
    if on:
        param = 0x00
    else:
        param = 0x01

    raw = pack_request(0x9F, 0x03, 0x06, param) #set port bit - 0 to turn it on 1 to turn it off

    dev.write(1, raw, 0, 100)

    bytes = dev.read(0x81, packet_len, 0, 100)
    show_result(bytes)



def main():
    #initialising debuging - don't have a clue if this will work
    os.environ['PYUSB_LOG_FILENAME'] = 'debug'

    dev = usb.core.find(idVendor=0x0B38, idProduct=0x0010)

    # was it found?
    if dev is None:
        raise ValueError('Device not found')

    try:
        dev.detach_kernel_driver(0)
    except: # this usually mean that kernel driver has already been dettached
        pass

    # set the active configuration, the device has 2 configurations you can see them
    # by using: lsusb -vvv -d 0x0b40:
    # this device has configurations 1 and 2 I'm using the first one, not sure at the
    # moment if 2nd would work the same
    dev.set_configuration(1)


    #removed following lines if you're running this from command line
    #my netbeans didn't want to show standard output so I had to redirect it to
    #a file
    fsock = open('out.log', 'w')
    sys.stdout = fsock
    fsock2 = open('out.err', 'w')
    sys.stderr = fsock2


    #prepare our own command - this is get firmware id, only the first byte is
    #significant
    raw = pack_request(0x94)

    #send the packet
    dev.write(1, raw, 0, 100)

    #then read the result
    bytes = dev.read(0x81, packet_len, 0, 100)
    show_result(bytes)

    #prepare another request
    #set register TRISC bit 6 - port C bit 6 to be output
    #mind though 0x9B command cian be used to write any register, so check the
    #microcontroller's datasheet
    raw = pack_request(0x9B, 0x94, 0x06, 0x00)

    dev.write(1, raw, 0, 100)

    bytes = dev.read(0x81, packet_len, 0, 100)
    show_result(bytes)


    #once we have our bit set as output we can control it. Here, LED is turned
    #on and then turned off after a second and it's done 10 times
    for i in range(10):
        set_led(True, dev)
        time.sleep(1)
        set_led(False, dev)
        time.sleep(1)

    #done


if __name__ == '__main__':
  main()