89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
#include <libopencm3/cm3/nvic.h>
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#include <libopencm3/stm32/exti.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/rcc.h>
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#include <stdint.h>
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#include <stddef.h>
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#include "encoder.h"
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static volatile int pos;
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static void check(void);
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#define PIN_OPEN GPIO1
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#define PIN_OPEN_IRQ NVIC_EXTI1_IRQ
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#define PIN_CLOSE GPIO2
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#define PIN_CLOSE_IRQ NVIC_EXTI2_IRQ
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#define PIN_PORT GPIOC
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#define PIN_RCC RCC_GPIOC
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void encoder_setup(void) {
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rcc_periph_clock_enable(PIN_RCC);
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gpio_mode_setup(PIN_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, PIN_OPEN | PIN_CLOSE);
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exti_select_source(PIN_OPEN | PIN_CLOSE, PIN_PORT);
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exti_set_trigger(PIN_OPEN | PIN_CLOSE, EXTI_TRIGGER_BOTH);
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exti_enable_request(PIN_OPEN | PIN_CLOSE);
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nvic_enable_irq(PIN_OPEN_IRQ);
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nvic_enable_irq(PIN_CLOSE_IRQ);
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}
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int encoder_get() {
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return pos;
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}
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static int prev = 0;
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void check(void) {
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int pp = pos;
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int now = GPIO_IDR(PIN_PORT);
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now = (!!(now & PIN_OPEN))<<0 | (!!(now & PIN_CLOSE)) << 1;
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#define NEITHER 0
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#define JUST_OPEN 1
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#define JUST_CLOSE 2
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#define BOTH 3
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#define WAS(x) ((x)<<2)
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#define IS(x) (x)
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switch (WAS(prev) + IS(now)) {
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case WAS(NEITHER) + IS(JUST_CLOSE):
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case WAS(JUST_OPEN) + IS(NEITHER):
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case WAS(JUST_CLOSE) + IS(BOTH):
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case WAS(BOTH) + IS(JUST_OPEN):
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pos--;
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break;
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case WAS(NEITHER) + IS(JUST_OPEN):
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case WAS(JUST_OPEN) + IS(BOTH):
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case WAS(BOTH) + IS(JUST_CLOSE):
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case WAS(JUST_CLOSE) + IS(NEITHER):
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pos++;
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break;
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default:
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prev = now;
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return;
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}
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#undef NEITHER
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#undef JUST_OPEN
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#undef JUST_CLOSE
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#undef BOTH
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#undef WAS
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#undef IS
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prev = now;
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if (pos < MIN_POS)
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pos = MIN_POS;
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if (pos > MAX_POS)
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pos = MAX_POS;
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}
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void exti1_isr(void) {
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exti_reset_request(EXTI1);
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check();
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}
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void exti2_isr(void) {
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exti_reset_request(EXTI2);
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check();
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}
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