AVR Freaks

Thanks for the reply! Just curious: have you actually tried the HAL:Driver:Timer code? I was using this code originally but was having an issue with hard faults being thrown when the ISR fired. To try and simplify, I bypassed establishing any "tasks" and went directly to the TCO Handler. I was wondering if it was something I was doing wrong (probably). But otherwise, my code is the same code as the HAL:Driver:Timer example: all the same lower-level functions, etc.  

Pardon the question: where do I find these Lite examples? I downloaded the ASF framework (though for whatever reason can't seem to get Studio to link to it); I don't recall seeing these Lite drivers. 

EDIT: Sorry, disregard, I see the Lite drivers in START. 

Marcus and Lars,

Thanks for the replies.

So I'm trying the Lite:TC:Timer example, and I'm still confused. I spec'd the parameters in START. The code it generates (even when checking the CPCTRG checkbox in START) loads no value into RC. So I added this with a value I thought would give me (about) a 1s tick (75Mhz clock w/ 128 clock prescaler), and added a LED toggle to the TC0 Handler, built the project, and ran it. The LED toggled at a rate I would estimate at 500mS (scope is in the workshop). So I added a "0" to my RC value, expecting this would slow the LED down by an order of magnitude. And instead, it now toggles faster than before. Added another "0", toggles even faster. OK, so remove a "0" from my original value, and: no difference. Removed ANOTHER "0", and now it's toggling faster than ever. 

What am I doing wrong? The results I'm seeing make no sense.    

#include "tc_lite.h"
#include "atmel_start_pins.h"

#define TC_CHANNEL_0 0
#define TC_CHANNEL_1 1
#define TC_CHANNEL_2 2
#define TC_CHANNEL_COUNT 3

/**
 * \brief TC IRQ callback type
 */
typedef void (*tc_channel_ptr)(uint32_t);

/* TC0 channel interrupt callback array */
tc_channel_ptr tc0_channel_cb[TC_CHANNEL_COUNT];

/**
 * \brief Initialize TC interface
 */
int8_t TIMER_0_init()
{

	/* TC0 Channel 0 configuration */

	hri_tc_write_CMR_reg(TC0, TC_CHANNEL_0, 3 << TC_CMR_TCCLKS_Pos | 1 << TC_CMR_CAPTURE_CPCTRG_Pos);

	hri_tc_write_IMR_reg(TC0, TC_CHANNEL_0, 1 << TC_IMR_CPCS_Pos);

	hri_tc_write_RC_reg(TC0, TC_CHANNEL_0,  586000);

	tc0_channel_cb[TC_CHANNEL_0] = NULL;
	NVIC_DisableIRQ(TC0_IRQn);
	NVIC_ClearPendingIRQ(TC0_IRQn);
	NVIC_EnableIRQ(TC0_IRQn);

	return 0;
}

void start_timer(const void *hw, uint8_t channel)
{
	if (channel < TC_CHANNEL_COUNT) {
		hri_tc_write_CCR_reg(hw, channel, TC_CCR_CLKEN | TC_CCR_SWTRG);
	}
}

void stop_timer(const void *hw, uint8_t channel)
{
	if (channel < TC_CHANNEL_COUNT) {
		hri_tc_write_CCR_reg(hw, channel, TC_CCR_CLKDIS);
	}
}

void tc_register_callback(void *hw, uint8_t channel, void *cb)
{
	ASSERT(hw && (channel < TC_CHANNEL_COUNT));
	if (hw == TC0) {
		tc0_channel_cb[channel] = cb;
	}
}

/* TC0 Channel 0 interrupt handler */
void TC0_Handler(void)
{
	uint32_t status;
	status = hri_tc_get_SR_reg(TC0, TC_CHANNEL_0, TC_SR_Msk);
	if (tc0_channel_cb[TC_CHANNEL_0] != NULL) {
		tc0_channel_cb[TC_CHANNEL_0](status);
	}

	gpio_toggle_pin_level(LED);
}

Jeez, I am embarrassed. I read that warning in the datasheet 10 times and kept saying to myself, well that doesn't apply to ME. 

This comes directly from START. The actual function writes to the IER reg; no idea why they opted to name the function "write_IMR_reg". 

static inline void hri_tc_write_IMR_reg(const void *const hw, uint8_t submodule_index, hri_tc_imr_reg_t data)
{
	((Tc *)hw)->TcChannel[submodule_index].TC_IER = data;
	((Tc *)hw)->TcChannel[submodule_index].TC_IDR = ~data;
}