157 lines
4.2 KiB
C
157 lines
4.2 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/cm3/nvic.h>
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#include <libopencm3/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/timer.h>
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static void delay(int count)
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{
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for (int i=0; i < count; i++) {
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__asm__("nop");
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}
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}
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static void gpio_setup(void)
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{
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/* Enable GPIOA clock. */
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/* Manually: */
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// RCC_APB2ENR |= RCC_APB2ENR_IOPCEN;
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/* Using API functions: */
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rcc_periph_clock_enable(RCC_GPIOB);
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/* Set GPIO5 (in GPIO port A) to 'output push-pull'. */
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/* Manually: */
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// GPIOA_CRH = (GPIO_CNF_OUTPUT_PUSHPULL << (((5 - 8) * 4) + 2));
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// GPIOA_CRH |= (GPIO_MODE_OUTPUT_2_MHZ << ((5 - 8) * 4));
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/* Using API functions: */
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gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
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gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO1);
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gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO2);
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}
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static void tim_setup(void)
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{
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nvic_enable_irq(NVIC_TIM3_IRQ);
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nvic_set_priority(NVIC_TIM3_IRQ, 1); // interupts will not work without it???
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rcc_periph_clock_enable(RCC_TIM3);
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rcc_periph_reset_pulse(RST_TIM3);
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timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
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timer_set_prescaler(TIM3, 1152); // set timer tickrate to 500khz
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//timer_set_oc_value(TIM3, TIM_OC1, 0x1000);
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timer_set_period(TIM3, 0xffff);
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timer_one_shot_mode(TIM3);
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timer_ic_set_input(TIM3, TIM_IC3, TIM_IC_IN_TI3);
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//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING); // TIM_IC_RISING
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//timer_ic_enable(TIM3, TIM_IC3);
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timer_enable_counter(TIM3);
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timer_enable_irq(TIM3, TIM_DIER_UIE);
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timer_enable_irq(TIM3, TIM_DIER_CC1IE); // end start condition
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timer_enable_irq(TIM3, TIM_DIER_CC3IE);
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// start condition
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gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO0);
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gpio_clear(GPIOB, GPIO0);
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}
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enum DHT11_STATE {
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DHT11_START,
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DHT11_RESPONSE,
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DHT11_BIT0,
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DHT11_BIT1,
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DHT11_END
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};
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int dht11_state = DHT11_START;
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void tim3_isr(void)
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{
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if (timer_get_flag(TIM3, TIM_SR_UIF)) // timer reached end
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{
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timer_clear_flag(TIM3, TIM_SR_UIF);
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//gpio_toggle(GPIOB, GPIO1);
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gpio_toggle(GPIOB, GPIO2);
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//timer_set_counter(TIM3, 0);
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//timer_clear_flag(TIM3, TIM_SR_UIF);
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//timer_set_oc_value(TIM3, TIM_OC1, 1000);
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} else if (timer_get_flag(TIM3, TIM_SR_CC1IF))
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{
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timer_clear_flag(TIM3, TIM_SR_CC3IF);
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if (dht11_state == DHT11_START){
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gpio_set(GPIOB, GPIO0);
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gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
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// setup timer to wait for start response from dht11
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timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING); // TIM_IC_RISING
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timer_ic_enable(TIM3, TIM_IC3);
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dht11_state = DHT11_START;
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}
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} else if (timer_get_flag(TIM3, TIM_SR_CC3IF)) // PB0 changed value
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{
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timer_clear_flag(TIM3, TIM_SR_CC3IF);
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if (timer_get_flag(TIM3, TIM_SR_CC3OF))
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{
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timer_clear_flag(TIM3, TIM_SR_CC3OF);
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}
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}
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}
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static void dht_start_signal(void)
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{
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gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO0);
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gpio_clear(GPIOB, GPIO0);
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delay(205000);
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//delay(30000);
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gpio_set(GPIOB, GPIO0);
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delay(100);
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gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
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}
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volatile int bla=0;
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int main(void)
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{
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rcc_clock_setup_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_72MHZ]);
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gpio_setup();
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tim_setup();
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/* Blink the LED (PA5) on the board. */
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while (1) {
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/* Using API function gpio_toggle(): */
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gpio_toggle(GPIOB, GPIO1); /* LED on/off */
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delay(4000000);
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dht_start_signal();
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}
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return 0;
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}
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