samd21-microsecond-delay

This library implements a microsecond-precision delay feature to be used with Atmel's SAMD21 and similar MCUs in that family. It uses TC3/TC4 to act as a 32-bit counter. It uses the ASF Atmel API. (http://asf.atmel.com/docs/latest/api.html)

Please note that the clock source configured in timer_counter_util.h is the Generic Clock 4:

#define     CLOCK_SOURCE                GCLK_GENERATOR_4

In order to get this API running properly, you must edit your conf_clocks.h file to make the GCLK4 section look like this:

/* Configure GCLK generator 4 */
/* Used in TC3/TC4 32-bit counter */
#  define CONF_CLOCK_GCLK_4_ENABLE                true
#  define CONF_CLOCK_GCLK_4_RUN_IN_STANDBY        false
#  define CONF_CLOCK_GCLK_4_CLOCK_SOURCE          SYSTEM_CLOCK_SOURCE_OSC8M
#  define CONF_CLOCK_GCLK_4_PRESCALER             1
#  define CONF_CLOCK_GCLK_4_OUTPUT_ENABLE         false

If you need to use other clock source, please use the same template and change it in the API header file as well.

Pay attention to the clock source.