Check position. Use variable for button time.

Makefile

@@ -8,7 +8,7 @@ COMFLAGS=-g -Os -pedantic -Wall
 CFLAGS=$(COMFLAGS) -std=c99 -D_POSIX_C_SOURCE=200809L
 CXXFLAGS=$(COMFLAGS) -std=c++17
 
-OBJS = usb.o adc.o ringbuffer.o uart.o buttons.o printf.o
+OBJS = usb.o adc.o ringbuffer.o uart.o buttons.o printf.o encoder.o
 BINARY ?= main
 DEVICE=STM32F405RG
 

buttons.c

@@ -19,13 +19,13 @@ static uint32_t open_ticks = 0;
 static uint32_t close_ticks = 0;
 
 void buttons_open(uint32_t ticks) {
-  gpio_set(BUTTON_PORT, OPEN_BUTTON);
+  gpio_clear(BUTTON_PORT, OPEN_BUTTON);
   printf("Open %lu", ticks);
   open_ticks = ticks;
 }
 
 void buttons_close(uint32_t ticks) {
-  gpio_set(BUTTON_PORT, CLOSE_BUTTON);
+  gpio_clear(BUTTON_PORT, CLOSE_BUTTON);
   printf("Close %lu", ticks);
   close_ticks = ticks;
 }
@@ -33,14 +33,14 @@ void buttons_close(uint32_t ticks) {
 void buttons_release(void) {
   open_ticks = close_ticks = 0;
   printf("Release");
-  gpio_clear(BUTTON_PORT, OPEN_BUTTON | CLOSE_BUTTON);
+  gpio_set(BUTTON_PORT, OPEN_BUTTON | CLOSE_BUTTON);
 }
 
 void buttons_tick(void) {
   if (open_ticks) {
     open_ticks--;
     if (!open_ticks) {
-      gpio_clear(BUTTON_PORT, OPEN_BUTTON);
+      gpio_set(BUTTON_PORT, OPEN_BUTTON);
       printf("Release open");
     }
   }
@@ -48,7 +48,7 @@ void buttons_tick(void) {
     close_ticks--;
     if (!close_ticks) {
       printf("Release close");
-      gpio_clear(BUTTON_PORT, CLOSE_BUTTON);
+      gpio_set(BUTTON_PORT, CLOSE_BUTTON);
     }
   }
 }

encoder.c

@@ -0,0 +1,74 @@
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/stm32/exti.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/rcc.h>
+#include <stdint.h>
+#include <stddef.h>
+#include "encoder.h"
+
+static volatile int pos;
+
+static void check(void);
+
+#define PIN1 GPIO4
+#define PIN1_IRQ NVIC_EXTI4_IRQ
+#define PIN2 GPIO5
+#define PIN2_IRQ NVIC_EXTI9_5_IRQ
+
+void encoder_setup(void) {
+        rcc_periph_clock_enable(RCC_GPIOA);
+
+        gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, PIN1 | PIN2);
+
+        /* Set up exti on A0 & A1 */
+        exti_select_source(PIN1 | PIN2, GPIOA);
+        exti_set_trigger(PIN1 | PIN2, EXTI_TRIGGER_BOTH);
+        exti_enable_request(PIN1 | PIN2);
+
+        nvic_enable_irq(PIN1_IRQ);
+        nvic_enable_irq(PIN2_IRQ);
+}
+
+int encoder_get() {
+        return pos;
+}
+
+static int prev = 0;
+void check(void) {
+        int pp = pos;
+        int now = GPIO_IDR(GPIOA);
+        now = (!!(now & PIN1))<<0 | (!!(now & PIN2)) << 1;
+
+        switch (prev << 2 | now) {
+        case 0 * 4 + 2:
+        case 1 * 4 + 0:
+        case 2 * 4 + 3:
+        case 3 * 4 + 1:
+                pos++;
+                break;
+        case 0 * 4 + 1:
+        case 1 * 4 + 3:
+        case 2 * 4 + 0:
+        case 3 * 4 + 2:
+                pos--;
+                break;
+        default:
+                prev = now;
+                return;
+        }
+
+        prev = now;
+        if (pos < MIN_POS)
+                pos = MIN_POS;
+        if (pos > MAX_POS)
+                pos = MAX_POS;
+}
+
+void exti4_isr(void) {
+        exti_reset_request(EXTI4);
+        check();
+}
+void exti9_5_isr(void) {
+        exti_reset_request(EXTI5);
+        check();
+}

encoder.h

@@ -0,0 +1,11 @@
+#ifndef ENCODER_H
+#define ENCODER_H
+#define CLOSED_POS 220
+#define OPENED_POS 0
+
+#define MAX_POS ((CLOSED_POS > OPENED_POS) ? CLOSED_POS : OPENED_POS)
+#define MIN_POS ((CLOSED_POS < OPENED_POS) ? CLOSED_POS : OPENED_POS)
+
+void encoder_setup(void);
+int encoder_get(void);
+#endif

main.c

@@ -9,6 +9,9 @@
 #include "usb.h"
 #include "ringbuffer.h"
 #include "uart.h"
+#include "encoder.h"
+
+static const uint32_t button_time = 100;
 
 volatile uint32_t tick = 0;
 RINGBUFFER_STORAGE(usb_to_uart_buf, 64)
@@ -46,10 +49,12 @@ int main(void) {
   uart_setup();
   sys_tick_setup();
   buttons_setup();
+  encoder_setup();
 
   nvic_enable_irq(NVIC_USART3_IRQ);
 
   uint32_t last_tick = tick;
+  int last_pos = 0;
   while (1) {
     /* Handle control messages through the comms CDC */
     char buf[64];
@@ -66,14 +71,24 @@ int main(void) {
           printf("%lu", (unsigned long)adc_bat_voltage());
           break;
         case 'O':
-          buttons_open(15);
+          buttons_open(button_time);
           break;
         case 'C':
-          buttons_close(15);
+          buttons_close(button_time);
+          break;
+        case 'R':
+          printf("pos: %d", encoder_get());
           break;
       }
     }
 
+    int pos = encoder_get();
+    if (pos != last_pos && ringbuffer_empty(comm_out_buf)) {
+      printf("pos: %d", pos);
+      last_pos = pos;
+    }
+
+
     /* Send replies */
     if ((buf_len = ringbuffer_peek(comm_out_buf, &buf[0], sizeof buf))) {
       if (usb_write_cdcacm(ACM_COMM, (void *)buf, buf_len, 1)) {

printf.c

@@ -196,6 +196,7 @@ static int getint(char **s) {
 static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, int *nl_type)
 {
   char *a, *z, *s=(char *)fmt;
+  char buf[32];
   unsigned l10n=0, fl;
   int w, p, xp;
   union arg arg;
@@ -291,6 +292,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 
     if (!f) continue;
 
+    z = buf + sizeof(buf);
     prefix = "-+   0X0x";
     pl = 0;
     t = s[-1];