circuitpython/atmel-samd/tick.c
Scott Shawcroft ccbb5e84f9 This introduces an alternative hardware API called nativeio structured around different functions that are typically accelerated by native hardware. Its not meant to reflect the structure of the hardware.
Docs are here: http://tannewt-micropython.readthedocs.io/en/microcontroller/

It differs from upstream's machine in the following ways:

* Python API is identical across ports due to code structure. (Lives in shared-bindings)
* Focuses on abstracting common functionality (AnalogIn) and not representing structure (ADC).
* Documentation lives with code making it easy to ensure they match.
* Pin is split into references (board.D13 and microcontroller.pin.PA17) and functionality (DigitalInOut).
* All nativeio classes claim underlying hardware resources when inited on construction, support Context Managers (aka with statements) and have deinit methods which release the claimed hardware.
* All constructors take pin references rather than peripheral ids. Its up to the implementation to find hardware or throw and exception.
2016-11-21 14:11:52 -08:00

34 lines
941 B
C

#include "autoreset.h"
#include "tick.h"
#include "asf/sam0/drivers/tc/tc_interrupt.h"
// Global millisecond tick count
volatile uint64_t ticks_ms = 0;
static struct tc_module ms_timer;
static void ms_tick(struct tc_module *const module_inst) {
// SysTick interrupt handler called when the SysTick timer reaches zero
// (every millisecond).
ticks_ms += 1;
#ifdef AUTORESET_DELAY_MS
autoreset_tick();
#endif
}
void tick_init() {
struct tc_config config_tc;
tc_get_config_defaults(&config_tc);
config_tc.counter_size = TC_COUNTER_SIZE_16BIT;
config_tc.clock_prescaler = TC_CLOCK_PRESCALER_DIV1;
tc_set_top_value(&ms_timer, system_cpu_clock_get_hz() / 1000);
tc_init(&ms_timer, TC5, &config_tc);
tc_enable(&ms_timer);
tc_register_callback(&ms_timer, ms_tick, TC_CALLBACK_OVERFLOW);
tc_enable_callback(&ms_timer, TC_CALLBACK_OVERFLOW);
tc_start_counter(&ms_timer);
}