149 lines
3.8 KiB
C
149 lines
3.8 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2013 Joshua Harlan Lifton <joshua.harlan.lifton@gmail.com>
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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/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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/* Joystick definitions */
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#define JOY_PORT GPIOA
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#define JOY_STATE GPIOA_IDR
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#define JOY_LEFT GPIO0
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#define JOY_UP GPIO1
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#define JOY_DOWN GPIO2
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#define JOY_RIGHT GPIO3
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#define JOY_CENTER GPIO4
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#define JOY_ALL (JOY_LEFT | JOY_UP | JOY_DOWN | JOY_RIGHT | JOY_CENTER)
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#define JOY_DEBOUNCE_TICKS 20000
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/* LED array definitions */
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#define LED_PORT GPIOC
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#define LED1 GPIO9
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#define LED2 GPIO10
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#define LED3 GPIO11
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#define LED4 GPIO12
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#define LED_ALL (LED1 | LED2 | LED3 | LED4)
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#define BLINK_TICK 80000
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uint16_t joy_state;
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uint16_t led_state;
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bool led_blinking;
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/* Set STM32 to 24 MHz. */
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static void clock_setup(void)
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{
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rcc_clock_setup_in_hse_8mhz_out_24mhz();
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}
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static void led_setup(void)
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{
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/* Enable GPIOC clock. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
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/* Set LEDs to output push-pull. */
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gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ,
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GPIO_CNF_OUTPUT_PUSHPULL, LED_ALL);
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/* Turn off all LEDs. */
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gpio_clear(LED_PORT, LED_ALL);
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}
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static void joystick_setup(void)
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{
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/* Enable GPIOA clock. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN);
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/* Set joystick pins to input. */
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gpio_set_mode(JOY_PORT, GPIO_MODE_INPUT,
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GPIO_CNF_INPUT_PULL_UPDOWN,
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JOY_ALL);
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/* Enable all joystick pin pull-up resistors. */
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gpio_set(JOY_PORT, JOY_ALL);
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}
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int main(void)
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{
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int i = 0;
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int debounce = 0;
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clock_setup();
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led_setup();
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joystick_setup();
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joy_state = 0;
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led_state = LED1;
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led_blinking = false;
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while (1) {
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/* Set LED state according to joystick state. */
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joy_state = (~JOY_STATE) & JOY_ALL;
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if (joy_state != 0 && debounce == 0) {
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debounce = 1;
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gpio_clear(LED_PORT, LED_ALL);
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if (joy_state & JOY_UP) {
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if (led_state == LED_ALL || led_state == 0) {
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led_state = LED4;
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} else {
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led_state >>= 1;
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if (led_state < LED1) {
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led_state = LED4;
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}
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}
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} else if (joy_state & JOY_DOWN) {
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if (led_state == LED_ALL || led_state == 0) {
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led_state = LED1;
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} else {
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led_state <<= 1;
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if (led_state > LED4 || led_state == 0) {
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led_state = LED1;
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}
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}
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} else if (joy_state & JOY_LEFT) {
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led_state = LED_ALL;
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} else if (joy_state & JOY_RIGHT) {
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led_state = 0;
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} else if (joy_state & JOY_CENTER) {
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led_blinking = !led_blinking;
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}
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}
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/* Debounce joystick press. */
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else if (debounce > 0 && debounce < JOY_DEBOUNCE_TICKS) {
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debounce++;
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} else if (joy_state == 0 && debounce == JOY_DEBOUNCE_TICKS) {
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debounce++;
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}
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/* Debounce joystick release. */
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else if (debounce > JOY_DEBOUNCE_TICKS && debounce < 2*JOY_DEBOUNCE_TICKS) {
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debounce++;
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} else if (joy_state == 0 && debounce == 2*JOY_DEBOUNCE_TICKS) {
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debounce = 0;
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}
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/* Update LEDs on the fly rather than wait for blink to complete. */
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if (i++ < BLINK_TICK || !led_blinking) {
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gpio_set(LED_PORT, led_state);
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} else {
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gpio_clear(LED_PORT, led_state);
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}
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if (i > 2*BLINK_TICK) {
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i = 0;
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}
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}
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return 0;
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}
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