eb1279005c
Replace direct accesses to sched_active_thread and sched_active_pid with the helper functions thread_getpid() and thread_get_active(). This serves two purposes: 1. It makes accidental writes to those variable from outside core less likely. 2. Casting off the volatile qualifier is now well contained to those two functions
About
Test application for the HMC5883L 3-axis digital compass
Usage
The test application demonstrates the use of the HMC5883L. It uses the default configuration parameters.
- Continuous measurement at a Data Output Rate (DOR) of 15 Hz
- Normal mode, no biasing
- Gain 1090 LSB/Gs
- No averaging of data samples
The application can use different approaches to get new data:
- using the #hmc5883l_read function at a lower rate than the the DOR
- using the data-ready interrupt (DRDY), see #hmc5883l_init_int.
To use the data-ready interrupt (DRDY), the application has to enable
module hmc5883l_int and has to configure the GPIO to which the
interrupt signal is connected. This is done by overrding the default
configuration parameter HMC5883L_PARAM_INT_PIN if necessary, for example:
USEMODULE=hmc5883l_int CFLAGS='-DHMC5883L_PARAM_INT_PIN=GPIO_PIN\(0,12\)' \
make flash -C tests/driver_hmc5883l BOARD=...
The heading angle is calculated for a magnetic declination in radians defined
by HMC5883L_MAG_DECL. This depends on the current location. The value for
the current location can be determined at http://www.magnetic-declination.com/.