enum status_code events_allocate(
struct events_resource *resource,
struct events_config *config)
{
uint8_t new_channel;
Assert(resource);
new_channel = _events_find_first_free_channel_and_allocate();
if(new_channel == EVENTS_INVALID_CHANNEL) {
return STATUS_ERR_NOT_FOUND;
}
resource->channel = new_channel;
if (config->path != EVENTS_PATH_ASYNCHRONOUS) {
/* Set up a GLCK channel to use with the specific channel */
struct system_gclk_chan_config gclk_chan_conf;
system_gclk_chan_get_config_defaults(&gclk_chan_conf);
gclk_chan_conf.source_generator =
(enum gclk_generator)config->clock_source;
system_gclk_chan_set_config(EVSYS_GCLK_ID_0 + new_channel, &gclk_chan_conf);
system_gclk_chan_enable(EVSYS_GCLK_ID_0 + new_channel);
}
/* Save channel setting and configure it after user multiplexer */
resource->channel_reg = EVSYS_CHANNEL_EVGEN(config->generator) |
EVSYS_CHANNEL_PATH(config->path) |
((uint32_t)config->run_in_standby << EVSYS_CHANNEL_RUNSTDBY_Pos) |
((uint32_t)config->on_demand << EVSYS_CHANNEL_ONDEMAND_Pos) |
EVSYS_CHANNEL_EDGSEL(config->edge_detect);
return STATUS_OK;
}
void cal_init(void) {
// CONFIGURE EIC
// configure PA21 (INT from RTC, EXTINT5) input as EIC interrupt
PORT->Group[0].PMUX[21/2].bit.PMUXO = PORT_PMUX_PMUXO_A_Val;
PORT->Group[0].PINCFG[21].bit.PMUXEN = 1;
// enable EIC clock
PM->APBAMASK.reg |= PM_APBAMASK_EIC;
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EIC_GCLK_ID) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0);
// configure EXTINT5 to pass through EXTINT5 without any filtering/retiming
EIC->CONFIG[0].bit.FILTEN5 = 0;
EIC->CONFIG[0].bit.SENSE5 = EIC_CONFIG_SENSE5_HIGH_Val;
// enable event for this interrupt
EIC->EVCTRL.bit.EXTINTEO5 = 1;
// enable EIC!
EIC->CTRL.reg = EIC_CTRL_ENABLE;
// CONFIGURE EVENT SYSTEM
// enable event system clock
PM->APBCMASK.reg |= PM_APBCMASK_EVSYS;
// enable event channel 0 CLK
// use GCLK generator 0 for now, we'll change this to GCLK1 later
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | GCLK_CLKCTRL_ID_EVSYS_CHANNEL_0;
// event generator 0x11 is EXTINT5 and is a copy of what's on the IO pin.
// resynchronize to the local GCLK and detect a falling edge.
EVSYS->CHANNEL.reg = EVSYS_CHANNEL_EDGSEL_FALLING_EDGE |
EVSYS_CHANNEL_PATH_RESYNCHRONIZED |
EVSYS_CHANNEL_EVGEN(0x11) |
EVSYS_CHANNEL_CHANNEL(0);
// event user 0x02 is TC2
// note that EVSYS_USER_CHANNEL(1) actually configures channel 0!
EVSYS->USER.reg = EVSYS_USER_CHANNEL(1) | EVSYS_USER_USER(0x02);
// CONFIGURE TC2
// Use GCLK0 to clock timer while we configure it, we'll change it to GCLK1 later
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID_TC2_TC3;
// enable APB clock (also enable TC3 clock, though it's probably not needed)
PM->APBCMASK.reg |= PM_APBCMASK_TC2 | PM_APBCMASK_TC3;
// 32 bit mode, top=CC0
TC2->COUNT32.CTRLA.reg = TC_CTRLA_RUNSTDBY | TC_CTRLA_PRESCALER_DIV1 | TC_CTRLA_WAVEGEN_MFRQ | TC_CTRLA_MODE_COUNT32 | (0<<TC_CTRLA_ENABLE_Pos);
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// overflow every 16M samples, this makes subtracting time easy.
TC2->COUNT32.CC[0].reg = CAPTURE_VALUE_MASK;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// zero counter
TC2->COUNT32.COUNT.reg = 0;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// clear ONESHOT and DIR bits, so we count upwards and repeat
TC2->COUNT32.CTRLBCLR.reg = TC_CTRLBCLR_ONESHOT | TC_CTRLBCLR_DIR;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// enable capture channel 1
TC2->COUNT32.CTRLC.reg = TC_CTRLC_CPTEN1;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// enable event input
TC2->COUNT32.EVCTRL.reg = TC_EVCTRL_TCEI | TC_EVCTRL_EVACT_OFF;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// clear any pending interrupt flags
TC2->COUNT32.INTFLAG.reg = TC_INTFLAG_MC1 | TC_INTFLAG_OVF | TC_INTFLAG_SYNCRDY;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// and fire away!
TC2->COUNT32.CTRLA.bit.ENABLE = 1;
while(TC2->COUNT32.STATUS.bit.SYNCBUSY);
// now switch GCLKs for event and timer to GCLK1
//GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | GCLK_CLKCTRL_ID_TC2_TC3;
//GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | GCLK_CLKCTRL_ID_EVSYS_CHANNEL_0;
}