init - display test

new idf project (with  idf.py create-project)
add 2 components for encoder and display:
    https://github.com/DavidAntliff/esp32-rotary-encoder
    https://github.com/UncleRus/esp-idf-lib/tree/master/components/max7219
add code for testing a 7 segment display

main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "main.c"
+                    INCLUDE_DIRS ".")

main/main.c

@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <esp_idf_version.h>
+#include <max7219.h>
+
+#ifndef APP_CPU_NUM
+#define APP_CPU_NUM PRO_CPU_NUM
+#endif
+
+#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(4, 0, 0)
+#define HOST    HSPI_HOST
+#else
+#define HOST    SPI2_HOST
+#endif
+
+#define DISPLAY_PIN_NUM_MOSI 23
+#define DISPLAY_PIN_NUM_CLK 18
+#define DISPLAY_PIN_NUM_CS 21
+#define DISPLAY_DELAY 2000
+
+void task(void *pvParameter)
+{
+    // Configure SPI bus
+    spi_bus_config_t cfg = {
+       .mosi_io_num = DISPLAY_PIN_NUM_MOSI,
+       .miso_io_num = -1,
+       .sclk_io_num = DISPLAY_PIN_NUM_CLK,
+       .quadwp_io_num = -1,
+       .quadhd_io_num = -1,
+       .max_transfer_sz = 0,
+       .flags = 0
+    };
+    ESP_ERROR_CHECK(spi_bus_initialize(HOST, &cfg, 1));
+
+    // Configure device
+    max7219_t dev = {
+       .cascade_size = 1,
+       .digits = 8,
+       .mirrored = true
+    };
+    ESP_ERROR_CHECK(max7219_init_desc(&dev, HOST, MAX7219_MAX_CLOCK_SPEED_HZ, DISPLAY_PIN_NUM_CS));
+
+    char buf[10]; // 8 digits + decimal point + \0
+
+    ESP_ERROR_CHECK(max7219_init(&dev));
+
+    float count = 0;
+
+    while (1)
+    {
+//        printf("Display cycle\n");
+//
+//        max7219_clear(&dev);
+//        max7219_draw_text_7seg(&dev, 0, "12345678");
+//        printf("num");
+//        vTaskDelay(pdMS_TO_TICKS(DISPLAY_DELAY));
+//
+//        max7219_clear(&dev);
+//        max7219_draw_text_7seg(&dev, 0, "ABCDEFGH");
+//        printf("text");
+//        vTaskDelay(pdMS_TO_TICKS(DISPLAY_DELAY));
+//
+
+        if (count > 20){
+            count = 0;
+        } else {
+            count += 0.005;
+        }
+
+        sprintf(buf, "%06.3f m", count);
+        //printf("float num\n");
+        max7219_clear(&dev);
+        max7219_draw_text_7seg(&dev, 0, buf);
+        vTaskDelay(pdMS_TO_TICKS(10));
+
+   //     max7219_clear(&dev);
+   //     sprintf(buf, "%08x", 12345678);
+   //     printf("num\n");
+   //     max7219_draw_text_7seg(&dev, 0, buf);
+   //     vTaskDelay(pdMS_TO_TICKS(DISPLAY_DELAY));
+    }
+}
+
+void app_main()
+{
+    xTaskCreatePinnedToCore(task, "task", configMINIMAL_STACK_SIZE * 3, NULL, 5, NULL, APP_CPU_NUM);
+}
+
+