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Add examples making use of the RTC

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Add an example using the RTC to help with a lower power design.  This is
a sister example to the existing "button-irq-printf", which is
functionally identical, but uses far less power.

There's more tricks that can be done to lower the power even further,
but this shows a few of the early steps that can be done, using the RTC
wakeup instead of a timer.
This commit is contained in:
Karl Palsson
2013-01-23 00:01:46 +00:00
parent e5b3250382
commit d9fb4f7401
11 changed files with 508 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
examples/stm32/l1/stm32l-discovery/button-irq-printf/main.c
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@@ -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;