MAX7219/MAX7221 dirver + example

extras/max7219/max7219.h

@@ -0,0 +1,96 @@
+/*
+ * Driver for MAX7219/MAX7221
+ * Serially Interfaced, 8-Digit LED Display Drivers
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2017 Ruslan V. Uss <unclerus@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef EXTRAS_MAX7219_H_
+#define EXTRAS_MAX7219_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#define MAX7219_MAX_CASCADE_SIZE 8
+#define MAX7219_MAX_BRIGHTNESS   31
+
+/**
+ * Display descriptor
+ */
+typedef struct
+{
+    uint8_t cs_pin;              //!< GPIO connected to CS/LOAD pin
+
+    uint8_t digits;              //!< Accessible digits in 7seg. Up to cascade_size * 8
+
+    uint8_t cascade_size;        //!< Up to 8 MAX721xx cascaded
+    bool mirrored;               //!< true for horizontally mirrored displays
+
+    bool bcd;
+} max7219_display_t;
+
+/**
+ * Initialize display: switch it to normal operation from shutdown mode,
+ * set scan limit to the max and clear
+ * @param disp Pointer to display descriptor
+ * @return false if error occured
+ */
+bool max7219_init(max7219_display_t *disp);
+
+/**
+ * Set decode mode and clear display
+ * @param disp Pointer to display descriptor
+ * @param bcd true to set BCD decode mode, false to normal
+ */
+void max7219_set_decode_mode(max7219_display_t *disp, bool bcd);
+
+/**
+ * Set display brightness
+ * @param disp Pointer to display descriptor
+ * @param value Brightness value, 0..MAX7219_MAX_BRIGHTNESS
+ */
+void max7219_set_brightness(const max7219_display_t *disp, uint8_t value);
+
+/**
+ * Shutdown display or set it to normal mode
+ * @param disp Pointer to display descriptor
+ * @param shutdown Shutdown display if true
+ */
+void max7219_set_shutdown_mode(const max7219_display_t *disp, bool shutdown);
+
+/**
+ * Write data to display digit
+ * @param disp Pointer to display descriptor
+ * @param digit Digit index, 0..disp->digits - 1
+ * @param val Data
+ * @return false if error occured
+ */
+bool max7219_set_digit(const max7219_display_t *disp, uint8_t digit, uint8_t val);
+
+/**
+ * Clear display
+ * @param disp Pointer to display descriptor
+ */
+void max7219_clear(const max7219_display_t *disp);
+
+/**
+ * Draw text.
+ * Currently only 7-segment displays supported
+ * @param disp Pointer to display descriptor
+ * @param pos Start digit
+ * @param s Text
+ */
+void max7219_draw_text(const max7219_display_t *disp, uint8_t pos, const char *s);
+
+#ifdef __cplusplus
+extern "C"
+}
+#endif
+
+#endif /* EXTRAS_MAX7219_H_ */