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stm32: morse timer: standardize example

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Simplify, clarify and synchronize the two morse LED blinker examples.
Prepare for one day extracting the core as common morse example code.
This commit is contained in:
Karl Palsson
2016-12-17 00:21:19 +00:00
parent d2abd471a5
commit 9af2b8c7fb
4 changed files with 143 additions and 120 deletions
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142
examples/stm32/f1/stm32-h103/timer/timer.c
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@@ -17,40 +17,50 @@
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/timer.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/exti.h>
#include <libopencmsis/core_cm3.h>
uint16_t frequency_sequence[18] = {
1000,
500,
1000,
500,
1000,
500,
2000,
500,
2000,
500,
2000,
500,
1000,
500,
1000,
500,
1000,
5000,
#ifndef ARRAY_LEN
#define ARRAY_LEN(array) (sizeof((array))/sizeof((array)[0]))
#endif
#define LED1_PORT GPIOC
#define LED1_PIN GPIO12
/* Morse standard timings */
#define ELEMENT_TIME 500
#define DIT (1*ELEMENT_TIME)
#define DAH (3*ELEMENT_TIME)
#define INTRA (1*ELEMENT_TIME)
#define INTER (3*ELEMENT_TIME)
#define WORD (7*ELEMENT_TIME)
uint16_t frequency_sequence[] = {
DIT,
INTRA,
DIT,
INTRA,
DIT,
INTER,
DAH,
INTRA,
DAH,
INTRA,
DAH,
INTER,
DIT,
INTRA,
DIT,
INTRA,
DIT,
WORD,
};
int frequency_sel = 0;
uint16_t compare_time;
uint16_t new_time;
uint16_t frequency;
int debug = 0;
static void clock_setup(void)
{
rcc_clock_setup_in_hse_8mhz_out_72mhz();
@@ -58,14 +68,13 @@ static void clock_setup(void)
static void gpio_setup(void)
{
/* Enable GPIOC clock. */
/* Enable GPIO clock for leds. */
rcc_periph_clock_enable(RCC_GPIOC);
/* Set GPIO12 (in GPIO port C) to 'output push-pull'. */
gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
gpio_set(GPIOC, GPIO12);
/* Enable led as output */
gpio_set_mode(LED1_PORT, GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_PUSHPULL, LED1_PIN);
gpio_set(LED1_PORT, LED1_PIN);
}
static void tim_setup(void)
@@ -76,55 +85,42 @@ static void tim_setup(void)
/* Enable TIM2 interrupt. */
nvic_enable_irq(NVIC_TIM2_IRQ);
/* Reset TIM2 peripheral. */
/* Reset TIM2 peripheral to defaults. */
rcc_periph_reset_pulse(RST_TIM2);
/* Timer global mode:
* - No divider
* - Alignment edge
* - Direction up
* (These are actually default values after reset above, so this call
* is strictly unnecessary, but demos the api for alternative settings)
*/
timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT,
TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
/* Reset prescaler value. */
timer_set_prescaler(TIM2, 36000);
/*
* Please take note that the clock source for STM32 timers
* might not be the raw APB1/APB2 clocks. In various conditions they
* are doubled. See the Reference Manual for full details!
* In our case, TIM2 on APB1 is running at double frequency, so this
* sets the prescaler to have the timer run at 5kHz
*/
timer_set_prescaler(TIM2, ((rcc_apb1_frequency * 2) / 5000));
/* Disable preload. */
timer_disable_preload(TIM2);
/* Continous mode. */
timer_continuous_mode(TIM2);
/* Period (36kHz). */
/* count full range, as we'll update compare value continuously */
timer_set_period(TIM2, 65535);
/* Disable outputs. */
timer_disable_oc_output(TIM2, TIM_OC1);
timer_disable_oc_output(TIM2, TIM_OC2);
timer_disable_oc_output(TIM2, TIM_OC3);
timer_disable_oc_output(TIM2, TIM_OC4);
/* -- OC1 configuration -- */
/* Configure global mode of line 1. */
timer_disable_oc_clear(TIM2, TIM_OC1);
timer_disable_oc_preload(TIM2, TIM_OC1);
timer_set_oc_slow_mode(TIM2, TIM_OC1);
timer_set_oc_mode(TIM2, TIM_OC1, TIM_OCM_FROZEN);
/* Set the capture compare value for OC1. */
timer_set_oc_value(TIM2, TIM_OC1, 1000);
/* ---- */
/* ARR reload enable. */
timer_disable_preload(TIM2);
/* Set the initual output compare value for OC1. */
timer_set_oc_value(TIM2, TIM_OC1, frequency_sequence[frequency_sel++]);
/* Counter enable. */
timer_enable_counter(TIM2);
/* Enable commutation interrupt. */
/* Enable Channel 1 compare interrupt to recalculate compare values */
timer_enable_irq(TIM2, TIM_DIER_CC1IE);
}
@@ -139,18 +135,19 @@ void tim2_isr(void)
* Get current timer value to calculate next
* compare register value.
*/
compare_time = timer_get_counter(TIM2);
uint16_t compare_time = timer_get_counter(TIM2);
/* Calculate and set the next compare value. */
frequency = frequency_sequence[frequency_sel++];
new_time = compare_time + frequency;
uint16_t frequency = frequency_sequence[frequency_sel++];
uint16_t new_time = compare_time + frequency;
timer_set_oc_value(TIM2, TIM_OC1, new_time);
if (frequency_sel == 18)
if (frequency_sel == ARRAY_LEN(frequency_sequence)) {
frequency_sel = 0;
}
/* Toggle LED to indicate compare event. */
gpio_toggle(GPIOC, GPIO12);
gpio_toggle(LED1_PORT, LED1_PIN);
}
}
@@ -160,8 +157,17 @@ int main(void)
gpio_setup();
tim_setup();
while (1)
__asm("nop");
/* Loop calling Wait For Interrupt. In older pre cortex ARM this is
* just equivalent to nop. On cortex it puts the cpu to sleep until
* one of the three occurs:
*
* a non-masked interrupt occurs and is taken
* an interrupt masked by PRIMASK becomes pending
* a Debug Entry request
*/
while (1) {
__WFI(); /* Wait For Interrupt. */
}
return 0;
}