Write driver for 7-segment display

components/display/CMakeLists.txt

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+idf_component_register(
+  SRCS "display_driver.c"
+  INCLUDE_DIRS "."
+  REQUIRES driver fatal
+)

components/display/display_driver.c

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+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#include "display_driver.h"
+
+#include "fatal.h"
+
+#include "driver/gpio.h"
+#include "esp_log.h"
+#include <string.h>
+
+#define TAG "Display driver"
+
+#define PIN_BITMASK(n) ((uint64_t)1 << n)
+
+#define DIGIT_1_SELECT_PIN GPIO_NUM_15
+#define DIGIT_2_SELECT_PIN GPIO_NUM_2
+#define DIGIT_3_SELECT_PIN GPIO_NUM_0
+#define DIGIT_4_SELECT_PIN GPIO_NUM_4
+
+#define SEGMENT_A_PIN GPIO_NUM_16
+#define SEGMENT_B_PIN GPIO_NUM_23
+#define SEGMENT_C_PIN GPIO_NUM_19
+#define SEGMENT_D_PIN GPIO_NUM_5
+#define SEGMENT_E_PIN GPIO_NUM_17
+#define SEGMENT_F_PIN GPIO_NUM_22
+#define SEGMENT_G_PIN GPIO_NUM_21
+#define SEGMENT_DP_PIN GPIO_NUM_18
+
+static const gpio_num_t digit_select_pins[DISPLAY_DIGIT_COUNT] = {
+	[DISPLAY_DIGIT_1] = DIGIT_1_SELECT_PIN,
+	[DISPLAY_DIGIT_2] = DIGIT_2_SELECT_PIN,
+	[DISPLAY_DIGIT_3] = DIGIT_3_SELECT_PIN,
+	[DISPLAY_DIGIT_4] = DIGIT_4_SELECT_PIN,
+};
+
+static const gpio_num_t segment_pins[DISPLAY_SEGMENT_COUNT] = {
+	[DISPLAY_SEGMENT_A] = SEGMENT_A_PIN,
+	[DISPLAY_SEGMENT_B] = SEGMENT_B_PIN,
+	[DISPLAY_SEGMENT_C] = SEGMENT_C_PIN,
+	[DISPLAY_SEGMENT_D] = SEGMENT_D_PIN,
+	[DISPLAY_SEGMENT_E] = SEGMENT_E_PIN,
+	[DISPLAY_SEGMENT_F] = SEGMENT_F_PIN,
+	[DISPLAY_SEGMENT_G] = SEGMENT_G_PIN,
+	[DISPLAY_SEGMENT_DP] = SEGMENT_DP_PIN,
+};
+
+static DisplayDigit active_digit;
+
+DisplayState display_state;
+
+void display_driver_init()
+{
+	esp_err_t error;
+
+	memset(&display_state, 0, sizeof(DisplayState));
+
+	active_digit = DISPLAY_DIGIT_1;
+
+	uint64_t digit_select_pin_bitmask = 0;
+	for (unsigned i = 0; i < DISPLAY_DIGIT_COUNT; ++i)
+		digit_select_pin_bitmask |= PIN_BITMASK(digit_select_pins[i]);
+	const gpio_config_t digit_select_gpio_config = {
+		.pin_bit_mask = digit_select_pin_bitmask,
+		.mode = GPIO_MODE_OUTPUT,
+	};
+	error = gpio_config(&digit_select_gpio_config);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error configuring digit select pins: %04x", error);
+		FATAL();
+	}
+
+	uint64_t segment_pin_bitmask = 0;
+	for (unsigned i = 0; i < DISPLAY_SEGMENT_COUNT; ++i)
+		segment_pin_bitmask |= PIN_BITMASK(segment_pins[i]);
+	const gpio_config_t segment_gpio_config = {
+		.pin_bit_mask = segment_pin_bitmask,
+		.mode = GPIO_MODE_OUTPUT_OD,
+		.pull_down_en = GPIO_PULLDOWN_ENABLE,
+	};
+	error = gpio_config(&segment_gpio_config);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error configuring segment pins: %04x", error);
+		FATAL();
+	}
+}
+
+void display_driver_task(void *arg)
+{
+	(void)gpio_set_level(digit_select_pins[active_digit], 0);
+	active_digit = (active_digit + 1) % DISPLAY_DIGIT_COUNT;
+	(void)gpio_set_level(digit_select_pins[active_digit], 1);
+
+	for (unsigned i = 0; i < DISPLAY_SEGMENT_COUNT; ++i) {
+		(void)gpio_set_level(
+		    segment_pins[i], display_state[active_digit][i] ? 0 : 1);
+	}
+}

components/display/display_driver.h

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+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#ifndef DISPLAY_DRIVER_H
+#define DISPLAY_DRIVER_H
+
+#include <stdbool.h>
+
+typedef enum {
+	DISPLAY_SEGMENT_A,
+	DISPLAY_SEGMENT_B,
+	DISPLAY_SEGMENT_C,
+	DISPLAY_SEGMENT_D,
+	DISPLAY_SEGMENT_E,
+	DISPLAY_SEGMENT_F,
+	DISPLAY_SEGMENT_G,
+	DISPLAY_SEGMENT_DP,
+	DISPLAY_SEGMENT_COUNT,
+} DisplaySegment;
+
+typedef enum {
+	DISPLAY_DIGIT_1,
+	DISPLAY_DIGIT_2,
+	DISPLAY_DIGIT_3,
+	DISPLAY_DIGIT_4,
+	DISPLAY_DIGIT_COUNT,
+} DisplayDigit;
+
+typedef bool DisplayDigitState[DISPLAY_SEGMENT_COUNT];
+typedef DisplayDigitState DisplayState[DISPLAY_DIGIT_COUNT];
+
+/**
+ * The current state of the display.
+ */
+extern DisplayState display_state;
+
+/**
+ * Initialize the display driver.
+ */
+void display_driver_init();
+
+/**
+ * Driver update task; should be ran regularly with a short period.
+ */
+void display_driver_task(void *arg);
+
+#endif