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-rw-r--r--examples/stm32/l1/stm32l-discovery/button-irq-printf/README32
-rw-r--r--examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c74
-rw-r--r--examples/stm32/l1/stm32l-discovery/button-irq-printf/syscfg.h5
3 files changed, 96 insertions, 15 deletions
diff --git a/examples/stm32/l1/stm32l-discovery/button-irq-printf/README b/examples/stm32/l1/stm32l-discovery/button-irq-printf/README
index 63232ef..5de96a2 100644
--- a/examples/stm32/l1/stm32l-discovery/button-irq-printf/README
+++ b/examples/stm32/l1/stm32l-discovery/button-irq-printf/README
@@ -1,3 +1,35 @@
* Prints to the screen when the button is pushed/released (irq driven)
115200@8n1 console on PA2 (tx only)
+* uses basic timer 6 with overflows to generate a 1ms counter (not an ideal
+ use, but shows some api methods and can be demoed on the disco board)
+* uses basic timer 7 with the exti interrupts to do ghetto input capture.
+ Not as fast or precise as the real input capture modes, but can be used
+ on any gpio pin.
+
+No effort at saving power is made here. Current consumption on the Disco board
+is ~7.5mA when the green tick led is off, and about 10.5mA when it is on.
+
+example output:
+
+hi guys!
+TICK 0
+TICK 1
+TICK 2
+Pushed down!
+held: 443 ms
+Pushed down!
+TICK 3
+held: 217 ms
+Pushed down!
+held: 99 ms
+Pushed down!
+TICK 4
+held: 73 ms
+Pushed down!
+held: 60 ms
+TICK 5
+Pushed down!
+held: 98 ms
+Pushed down!
+
diff --git a/examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c b/examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c
index 762fdd9..82a3434 100644
--- a/examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c
+++ b/examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c
@@ -22,8 +22,9 @@
#include <unistd.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/l1/rcc.h>
-#include <libopencm3/stm32/l1/gpio.h>
+#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/exti.h>
+#include <libopencm3/stm32/timer.h>
#include <libopencm3/stm32/usart.h>
#include "syscfg.h"
@@ -32,17 +33,25 @@ static struct state_t state;
void clock_setup(void)
{
+ rcc_clock_setup_pll(&clock_config[CLOCK_VRANGE1_HSI_PLL_24MHZ]);
/* Lots of things on all ports... */
rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOAEN);
rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOBEN);
/* Enable clocks for USART2. */
rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN);
+
+ /* And timers. */
+ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_TIM6EN);
+ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_TIM7EN);
+
}
void gpio_setup(void)
{
+ /* green led for ticking, blue for button feedback */
gpio_mode_setup(LED_DISCO_GREEN_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_DISCO_GREEN_PIN);
+ gpio_mode_setup(LED_DISCO_BLUE_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_DISCO_BLUE_PIN);
/* Setup GPIO pins for USART2 transmit. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2);
@@ -92,18 +101,61 @@ void BUTTON_DISCO_USER_isr(void)
{
exti_reset_request(BUTTON_DISCO_USER_EXTI);
if (state.falling) {
+ gpio_clear(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
state.falling = false;
exti_set_trigger(BUTTON_DISCO_USER_EXTI, EXTI_TRIGGER_RISING);
- // ILOG("fell: %d\n", TIM_CNT(TIM7));
- puts("fell!\n");
+ unsigned int x = TIM_CNT(TIM7);
+ printf("held: %u ms\n", x);
} else {
- puts("Rose!\n");
- // TIM_CNT(TIM7) = 0;
+ gpio_set(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
+ printf("Pushed down!\n");
+ TIM_CNT(TIM7) = 0;
state.falling = true;
exti_set_trigger(BUTTON_DISCO_USER_EXTI, EXTI_TRIGGER_FALLING);
}
}
+static volatile int t6ovf = 0;
+
+void tim6_isr(void)
+{
+ TIM_SR(TIM6) &= ~TIM_SR_UIF;
+ if (t6ovf++ > 1000) {
+ printf("TICK %d\n", state.tickcount++);
+ t6ovf = 0;
+ gpio_toggle(LED_DISCO_GREEN_PORT, LED_DISCO_GREEN_PIN);
+ }
+}
+
+/*
+ * Another ms timer, this one used to generate an overflow interrupt at 1ms
+ * It is used to toggle leds and write tick counts
+ */
+void setup_tim6(void)
+{
+ timer_reset(TIM6);
+ // 24Mhz / 10khz -1.
+ timer_set_prescaler(TIM6, 2399); // 24Mhz/10000hz - 1
+ // 10khz for 10 ticks = 1 khz overflow = 1ms overflow interrupts
+ timer_set_period(TIM6, 10);
+
+ nvic_enable_irq(NVIC_TIM6_IRQ);
+ timer_enable_update_event(TIM6); // default at reset!
+ timer_enable_irq(TIM6, TIM_DIER_UIE);
+ timer_enable_counter(TIM6);
+}
+
+/*
+ * Free running ms timer.
+ */
+void setup_tim7(void)
+{
+ timer_reset(TIM7);
+ timer_set_prescaler(TIM7, 23999); // 24Mhz/1000hz - 1
+ timer_set_period(TIM7, 0xffff);
+ timer_enable_counter(TIM7);
+}
+
void setup_buttons(void)
{
/* Enable EXTI0 interrupt. */
@@ -120,19 +172,15 @@ void setup_buttons(void)
int main(void)
{
- int i;
- int j = 0;
clock_setup();
gpio_setup();
usart_setup();
- puts("hi guys!\n");
+ printf("hi guys!\n");
setup_buttons();
+ setup_tim6();
+ setup_tim7();
while (1) {
- puts("tick:");
- putchar('a' + (j++ % 26));
- gpio_toggle(GPIOB, GPIO7); /* LED on/off */
- for (i = 0; i < 100000; i++) /* Wait a bit. */
- __asm__("NOP");
+ ;
}
return 0;
diff --git a/examples/stm32/l1/stm32l-discovery/button-irq-printf/syscfg.h b/examples/stm32/l1/stm32l-discovery/button-irq-printf/syscfg.h
index be54502..d278ac4 100644
--- a/examples/stm32/l1/stm32l-discovery/button-irq-printf/syscfg.h
+++ b/examples/stm32/l1/stm32l-discovery/button-irq-printf/syscfg.h
@@ -24,8 +24,8 @@
extern "C" {
#endif
-#include <libopencm3/stm32/l1/gpio.h>
-#include <libopencm3/stm32/l1/nvic.h>
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/exti.h>
#include <libopencm3/stm32/usart.h>
@@ -46,6 +46,7 @@ extern "C" {
struct state_t {
bool falling;
+ int tickcount;
};