diff --git a/examples/stm32/f1/stm32-h103/timer/README.md b/examples/stm32/f1/stm32-h103/timer/README.md
new file mode 100644
index 0000000..e862d55
--- /dev/null
+++ b/examples/stm32/f1/stm32-h103/timer/README.md
@@ -0,0 +1,15 @@
+# README
+
+This example demonstrates the use of timers to trigger an interrupt. This
+example will toggle a LED spelling out the following morse code:
+
+SOS -> ...---...
+
+using international morse timing, with a dot element of 100ms
+
+It's intended for the olimex stm32-h103 eval board. It should blink
+a LED on the board.
+
+## Board connections
+
+*none required*
diff --git a/examples/stm32/f1/stm32-h103/timer/timer.c b/examples/stm32/f1/stm32-h103/timer/timer.c
index f228317..7eefcaa 100644
--- a/examples/stm32/f1/stm32-h103/timer/timer.c
+++ b/examples/stm32/f1/stm32-h103/timer/timer.c
@@ -17,40 +17,50 @@
* along with this library. If not, see .
*/
+#include
#include
#include
#include
-#include
-#include
+#include
-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;
}
diff --git a/examples/stm32/f4/stm32f4-discovery/timer/README.md b/examples/stm32/f4/stm32f4-discovery/timer/README.md
index 55e1006..5ab17cb 100644
--- a/examples/stm32/f4/stm32f4-discovery/timer/README.md
+++ b/examples/stm32/f4/stm32f4-discovery/timer/README.md
@@ -1,14 +1,14 @@
# README
This example demonstrates the use of timers to trigger an interrupt. This
-example will toggle two LEDs spelling out the following morse code:
+example will toggle a LED spelling out the following morse code:
SOS -> ...---...
-Where dots are .1s, dashes .2s, gaps .05s and the word pause .5s.
+using international morse timing, with a dot element of 100ms
It's intended for the ST STM32F4DISCOVERY eval board. It should blink
-the LEDs on the board.
+a LED on the board.
## Board connections
diff --git a/examples/stm32/f4/stm32f4-discovery/timer/timer.c b/examples/stm32/f4/stm32f4-discovery/timer/timer.c
index b9cf04c..dba139c 100644
--- a/examples/stm32/f4/stm32f4-discovery/timer/timer.c
+++ b/examples/stm32/f4/stm32f4-discovery/timer/timer.c
@@ -22,41 +22,45 @@
#include
#include
#include
-#include
-
#include
#ifndef ARRAY_LEN
#define ARRAY_LEN(array) (sizeof((array))/sizeof((array)[0]))
#endif
-uint16_t frequency_sequence[18] = {
- 1000,
- 500,
- 1000,
- 500,
- 1000,
- 500,
- 2000,
- 500,
- 2000,
- 500,
- 2000,
- 500,
- 1000,
- 500,
- 1000,
- 500,
- 1000,
- 5000,
+#define LED1_PORT GPIOD
+#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,
};
-uint16_t frequency_sel = 0;
-
-uint16_t compare_time;
-uint16_t new_time;
-uint16_t frequency;
-int debug = 0;
+int frequency_sel = 0;
static void clock_setup(void)
{
@@ -68,12 +72,9 @@ static void gpio_setup(void)
/* Enable GPIO clock for leds. */
rcc_periph_clock_enable(RCC_GPIOD);
- /* Set GPIO12 (in GPIO port D) to 'output push-pull'. */
- gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT,
- GPIO_PUPD_NONE, GPIO12 | GPIO13);
-
- gpio_set(GPIOD, GPIO12);
- gpio_clear(GPIOD, GPIO13);
+ /* Enable led as output */
+ gpio_mode_setup(LED1_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED1_PIN);
+ gpio_set(LED1_PORT, LED1_PIN);
}
static void tim_setup(void)
@@ -95,15 +96,16 @@ static void tim_setup(void)
* 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);
- /*
- * Please take note that the clock source for STM32F4 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 10kHz
- */
- timer_set_prescaler(TIM2, ((rcc_apb1_frequency * 2) / 10000));
+ TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
+
+ /*
+ * 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);
@@ -113,7 +115,7 @@ static void tim_setup(void)
timer_set_period(TIM2, 65535);
/* Set the initual output compare value for OC1. */
- timer_set_oc_value(TIM2, TIM_OC1, 1000);
+ timer_set_oc_value(TIM2, TIM_OC1, frequency_sequence[frequency_sel++]);
/* Counter enable. */
timer_enable_counter(TIM2);
@@ -133,11 +135,11 @@ 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 == ARRAY_LEN(frequency_sequence)) {
@@ -145,8 +147,7 @@ void tim2_isr(void)
}
/* Toggle LED to indicate compare event. */
- gpio_toggle(GPIOD, GPIO12);
- gpio_toggle(GPIOD, GPIO13);
+ gpio_toggle(LED1_PORT, LED1_PIN);
}
}
@@ -164,8 +165,9 @@ int main(void)
* an interrupt masked by PRIMASK becomes pending
* a Debug Entry request
*/
- while (1)
+ while (1) {
__WFI(); /* Wait For Interrupt. */
+ }
return 0;
}