[Paparazzi-devel] HMC5843 magnetometer

[cristina barrado]

Dear all,

At the ICARUS group (UPC-Barcelona Tech, Spain) we have been trying to 
set up a quadrotor for quite a long time. Thanks to Gautier and Michiel 
we had it almost set, but we still have some problems with the magnetometer.

We use a Booz2 with LPC21 and BoozIMUv-1.1. Since the magnetometer in 
the IMU was not working we tried to connect an HMC4853 
(http://store.diydrones.com/HMC5843_Triple_Axis_Magnetometer_p/br-hmc5843-01.htm) 
board using the I2C_1. The board is set for 5V, thus we connected it to 
the UART0+I2C_1 (LTranslated) connector.

Values read from magnetometer are still 0,0,0!! Software seems to be 
fine (some debugging using leds tells us that the I2C device is not 
responding). Then we looked at the oscilloscope and find out the the SDA 
lines of the I2C_1 were only 1.6V (while CLK line was fine!). The most 
surprising thing is that voltage levels are OK (close to 3V and 5V on 
each I2C_1 connector) when we disconnect the HMC board !!?

Has any of you work with the HMC board at 5V?? Do we need to add new 
pull up resistors? The Booz2 board already has them...

Thanks!

Cristina Barrado
Barcelona Tech