1 files changed, 291 insertions, 0 deletions
diff --git a/software/main.c b/software/main.c
new file mode 100644
index 0000000..5261d34
--- /dev/null
+++ b/software/main.c
@@ -0,0 +1,291 @@
+/*
+ * Traffic light
+ *
+ * Copyright (C) 2019-2022 Aurelien Jarno
+ *
+ * Authors:
+ *  Aurelien Jarno <aurelien@aurel32.net>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ * See the COPYING file in the same directory as this file.
+ */
+
+/**********************************************************************
+ * Global defines                                                     *
+ **********************************************************************/
+/* CPU */
+#define F_CPU                   8000000UL       /* 8 MHz */
+
+/* I/O pins */
+#define BUTTON                  PB0             /* Also DATA prog */
+#define LED_DATA                PB1             /* Also CLK prog */
+#define LED_PWR                 PB2
+#define RESET                   PB3
+
+
+/**********************************************************************
+ * Includes                                                           *
+ **********************************************************************/
+#include <avr/interrupt.h>
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/sleep.h>
+#include <avr/wdt.h>
+#include <stdint.h>
+#include <util/delay.h>
+
+
+/**********************************************************************
+ * State machine                                                      *
+ **********************************************************************/
+enum state {
+    state_off,
+    state_red,
+    state_orange,
+    state_green,
+    state_blinking_on,
+    state_blinking_off,
+};
+
+struct state_desc {
+    const struct __attribute__((__packed__)) {
+        uint8_t r;
+        uint8_t g;
+        uint8_t b;
+    } leds[3];
+    uint16_t duration;
+    enum state next;
+    enum state next_button_short;
+    enum state next_button_medium;
+    enum state next_button_long;
+};
+
+const struct state_desc states_desc[] = {
+    [state_off] = {
+        .leds = {
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+        },
+        .duration = 1,
+        .next = state_off,
+        .next_button_short = state_off,
+        .next_button_medium = state_off,
+        .next_button_long = state_off,
+    },
+
+    [state_green] = {
+        .leds = {
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x7f, .b = 0x00, },
+        },
+        .duration = 13000,
+        .next = state_orange,
+        .next_button_short = state_orange,
+        .next_button_medium = state_blinking_on,
+        .next_button_long = state_off,
+    },
+    [state_orange] = {
+        .leds = {
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x7f, .g = 0x2f, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+        },
+        .duration = 1500,
+        .next = state_red,
+        .next_button_short = state_red,
+        .next_button_medium = state_blinking_on,
+        .next_button_long = state_off,
+    },
+    [state_red] = {
+        .leds = {
+            { .r = 0x7f, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+        },
+        .duration = 15000,
+        .next = state_green,
+        .next_button_short = state_green,
+        .next_button_medium = state_blinking_on,
+        .next_button_long = state_off,
+    },
+
+    [state_blinking_on] = {
+        .leds = {
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x7f, .g = 0x2f, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+        },
+        .duration = 500,
+        .next = state_blinking_off,
+        .next_button_short = state_blinking_off,
+        .next_button_medium = state_red,
+        .next_button_long = state_off,
+    },
+    [state_blinking_off] = {
+        .leds = {
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+            { .r = 0x00, .g = 0x00, .b = 0x00, },
+        },
+        .duration = 500,
+        .next = state_blinking_on,
+        .next_button_short = state_blinking_on,
+        .next_button_medium = state_red,
+        .next_button_long = state_off,
+    },
+};
+
+
+/**********************************************************************
+ * Interrupt handlers                                                 *
+ **********************************************************************/
+/* Do nothing, this is only used to wake-up the MCU */
+EMPTY_INTERRUPT(PCINT0_vect);
+
+
+/**********************************************************************
+ * Functions                                                          *
+ **********************************************************************/
+static void set_leds(const uint8_t *data, uint8_t len)
+{
+    uint8_t outlo, outhi;
+
+    outlo = PORTB & ~(1 << LED_DATA);
+    outhi = PORTB | (1 << LED_DATA);
+
+    /* Reset signal */
+    PORTB = outlo;
+    _delay_us(280);
+
+    /* Send all bits */
+    for (uint8_t i = 0; i < len; i++) {
+        asm volatile(
+            "       ldi   __tmp_reg__, 8          \n\t"
+            "loop:                                \n\t"
+            "       out   %[port], %[outhi]       \n\t"
+            "       nop                           \n\t"
+            "       sbrs  %[data], 7              \n\t"
+            "       out   %[port], %[outlo]       \n\t"
+            "       lsl   %[data]                 \n\t"
+            "       nop                           \n\t"
+            "       nop                           \n\t"
+            "       out   %[port], %[outlo]       \n\t"
+            "       dec   __tmp_reg__             \n\t"
+            "       brne  loop                    \n\t"
+            :
+            : [data] "r" (data[i]),
+              [port] "I" (_SFR_IO_ADDR(PORTB)),
+              [outhi] "r" (outhi),
+              [outlo] "r" (outlo)
+            : "cc"
+        );
+    }
+}
+
+
+/**********************************************************************
+ * Main code                                                          *
+ **********************************************************************/
+int main(void)
+{
+    /* Initialization: disable interrupts, clear watchdog */
+    cli();
+    wdt_reset();
+
+    /* Switch to calibrated internal 8 MHz oscillator without prescaler,
+       corresponding to a 8 MHz CPU clock */
+    CCP = 0xD8;
+    CLKMSR = 0x00;
+    CCP = 0xD8;
+    CLKPSR = 0x00;
+
+    /* Disable unused peripherals: ANA_COMP, TIM0, VLM, WDT */
+    ACSR = (1 << ACD);
+    PRR = (1 << PRADC) | (1 << PRTIM0);
+    VLMCSR = 0x00;
+    CCP = 0xD8;
+    WDTCSR = 0x00;
+
+    /* Setup LED pins as low output, BUTTON and RESET pins as input with
+     * pull-up */
+    PORTCR = 0x00;
+    PORTB = 0x00;
+    PUEB = (1 << BUTTON) | (1 << RESET);
+    DDRB = (1 << LED_PWR) | (1 << LED_DATA);
+
+    /* Setup interrupt on button change */
+    PCMSK = (1 << PCINT0);
+    PCICR = (1 << PCIE0);
+
+    for (;;) {
+        /* Reset power-on duration and start with the red color */
+        uint32_t on_duration = 0;
+        uint16_t button_duration = 0;
+        enum state state = state_red;
+
+        /* Power-on the LED and wait for it to be ready */
+        PORTB |= (1 << LED_PWR);
+        _delay_ms(10);
+
+        /* Loop through all the states until reaching the off state */
+        while (state != state_off) {
+            set_leds((const uint8_t *)states_desc[state].leds,
+                     sizeof(states_desc[state].leds));
+
+            for (uint16_t d = states_desc[state].duration; d > 0; d--) {
+                _delay_ms(1);
+                on_duration++;
+
+                /* Count the button push time, and debounce the button by
+                 * ignoring short pulses. */
+                if ((PINB & (1 << BUTTON)) == 0) {
+                    if (button_duration != 65535) {
+                        button_duration++;
+                    }
+                } else if (button_duration > 10) {
+                    break;
+                } else {
+                    button_duration = 0;
+                }
+            }
+
+            if (((PINB & (1 << BUTTON)) != 0) && button_duration > 10) {
+                if (button_duration < 500) {
+                    state = states_desc[state].next_button_short;
+                } else if (button_duration < 1500) {
+                    state = states_desc[state].next_button_medium;
+                } else {
+                    state = states_desc[state].next_button_long;
+                }
+                on_duration = 0;
+                button_duration = 0;
+            } else if (on_duration > 1800000) {
+                state = state_off;
+            } else {
+                state = states_desc[state].next;
+            }
+        }
+
+        /* Power-off the LED */
+        PORTB &= ~(1 << LED_PWR);
+
+        /* Clear and allow interrupts to wake-up the MCU and go to power down mode */
+        PCIFR |= (1 << PCIF0);
+        set_sleep_mode(SLEEP_MODE_PWR_DOWN);
+        sei();
+        sleep_mode();
+
+        /* Returned from interrupt, disable interrupts */
+        cli();
+
+        /* Wait for the button to be released */
+        while ((PINB & (1 << BUTTON)) == 0) {
+            ;;
+        }
+    }
+
+    /* Never reached */
+    return 0;
+}