Pi i2c HMC5843 magnetometer sequence of write/reads

[mdsousa]

Hi

I'm trying to use quick2wire to communicate between my Pi (rev B) and an HMC5843 magnetometer.
When I run sudo i2cdetect -y 1 it shows the 5843 is assigned i2c address 1e. I've created a script to get some data from the 5843. Everytime I run my script, it returns some bytes showing empty [](as you can see, the example here shows the second and fourth are empty):
[b'\x10']
[b' ']
[b'\x10']
[b' ']
[b'\x10']
[b'\x01']

Sometimes I get an I/O error:
File "/usr/local/lib/python3.2/dist-packages/quick2wire_api-0.0.0.2-py3.2.egg/quick2wire/i2c.py", line 78, in transaction
ioctl(self.fd, I2C_RDWR, ioctl_arg)
IOError: [Errno 5] Input/output error

Sometimes I get both errors (empty brackets along withthe I/O error.

Here's is my code:

from quick2wire.i2c import I2CMaster, writing_bytes,reading
import time
address = 0x1e
with I2CMaster() as bus:
    # Get data from hmc5843 register
    # for continuous measurement mode, send bytes 0x3C 0x02 0x00
    bus.transaction(writing_bytes(address,0x3C))
    bus.transaction(writing_bytes(address,0x02))
    bus.transaction(writing_bytes(address,0x00))
    time.sleep(0.01) # allow to settle
    # want to start reading from address 0x03
    bus.transaction(writing_bytes(address,0x03))
    xLSB = bus.transaction(reading(address,1))
    xMSB = bus.transaction(reading(address,1))
    yLSB = bus.transaction(reading(address,1))
    yMSB = bus.transaction(reading(address,1))
    zMSB = bus.transaction(reading(address,1))
    zLSB = bus.transaction(reading(address,1))
    print(xLSB)
    print(xMSB)
    print(yLSB)
    print(yMSB)
    print(zLSB)
    print(zMSB)

Any idea what I am doing wrong? Thanks for your help...