Store application configuration in EEPROM.

src/main/CMakeLists.txt

@@ -8,7 +8,7 @@
 
 # -- Executable Configuration --
 
-# Note that for the main executable, we use the project forced to lowercase
+# Note that for the main executable, we use the project name forced to lowercase
 string(TOLOWER "${CMAKE_PROJECT_NAME}" EXECUTABLE_NAME)
 set(EXECUTABLE_SOURCE   application/buzzer.c
                         application/buzzer.h
@@ -22,18 +22,24 @@ set(EXECUTABLE_SOURCE   application/buzzer.c
                         application/keyer.h
                         application/led.c
                         application/led.h
+                        application/storage.c
+                        application/storage.h
                         application/wpm.c
                         application/wpm.h
                         core/main.c
                         core/sys.c
                         core/sys.h
                         core/version.c
                         core/version.h
+                        drivers/eeprom.c
+                        drivers/eeprom.h
                         drivers/gpio.c
                         drivers/gpio.h
                         drivers/usart.c
                         drivers/usart.h
                         utility/constants.h
+                        utility/crc.c
+                        utility/crc.h
                         utility/debug.c
                         utility/debug.h
                         utility/types.h

src/main/application/config.c

@@ -16,9 +16,26 @@
 #include "application/input.h"
 #include "application/keyer.h"
 #include "application/led.h"
+#include "application/storage.h"
+#include "core/sys.h"
 #include "utility/debug.h"
+#include "utility/types.h"
 #include "utility/utility.h"
 
+/* --------------------------------------------------- CONSTANTS ---------------------------------------------------- */
+
+/**
+ * @def     CONFIG_VERSION_CURRENT
+ * @brief   The currently active configuration version.
+ */
+#define CONFIG_VERSION_CURRENT  ( 1 )
+
+/**
+ * @def     MINIMUM_SAVE_PERIOD
+ * @brief   Minimum elapsed time between saving config to storage.
+ */
+#define MINIMUM_SAVE_PERIOD     ( 5 * TICKS_PER_SEC )
+
 /* ----------------------------------------------------- MACROS ----------------------------------------------------- */
 
 _Static_assert( _CONFIG_DFLT_WPM >= WPM_MINIMUM &&
@@ -31,9 +48,17 @@ _Static_assert( _CONFIG_DFLT_BUZZER_FREQUENCY >= BUZZER_MINIMUM_FREQUENCY &&
 /* --------------------------------------------------- VARIABLES ---------------------------------------------------- */
 
 static config_t s_config;                   /**< Currently active app configuration.    */
+static bool s_modified = false;             /**< Has the configuration been modified?   */
+static tick_t s_save_tick = 0;              /**< Tick config was last saved.            */
 
 /* ---------------------------------------------- PROCEDURE PROTOTYPES ---------------------------------------------- */
 
+/**
+ * @fn      flush( tick_t )
+ * @brief   Writes the configuration to non-volatile storage and updates state.
+ */
+static void flush( tick_t tick );
+
 /**
  * @fn      validate_config( config_t const * )
  * @brief   Returns `true` if all fields in the specified configuration struct are valid.
@@ -83,17 +108,31 @@ void config_default( config_t * config )
 }   /* config_default() */
 
 
+void config_flush( void )
+{
+    flush( sys_get_tick() );
+
+}   /* config_flush() */
+
+
 void config_get( config_t * config )
 {
-    memcpy( config, & s_config, sizeof( config_t ) );
+    * config = s_config;
 
 }   /* config_get() */
 
 
 void config_init( void )
 {
-    // Set configuration to defaults, for now
-    config_default( & s_config );
+    // Try to get configuration from storage, and restore defaults if that fails.
+    // In this case, any existing configuration will be lost the next time config is saved.
+    config_t config;
+    if( ! storage_get_config( CONFIG_VERSION_CURRENT, sizeof( config_t ), & config ) ||
+        ! validate_config( & config ) )
+        config_default( & config );
+
+    // Set local copy
+    s_config = config;
 
 }   /* config_init() */
 
@@ -110,12 +149,31 @@ bool config_set( config_t const * config )
     if( ! validate_config( config ) )
         return( false );
 
-    memcpy( & s_config, config, sizeof( config_t ) );
+    s_config = * config;
+    s_modified = true;
     return( true );
 
 }   /* config_set() */
 
 
+void config_tick( tick_t tick )
+{
+    if( ! s_modified || sys_elapsed( tick, s_save_tick ) < MINIMUM_SAVE_PERIOD )
+        return;
+    flush( tick );
+
+}   /* config_tick() */
+
+
+static void flush( tick_t tick )
+{
+    storage_set_config( CONFIG_VERSION_CURRENT, sizeof( config_t ), & s_config );
+    s_modified = false;
+    s_save_tick = tick;
+
+}   /* flush() */
+
+
 static bool validate_config( config_t const * config )
 {
     if( config->wpm < WPM_MINIMUM ||

src/main/application/config.h

@@ -57,6 +57,12 @@ typedef struct
 
 } config_t;
 
+/**
+ * @typedef config_version_t
+ * @brief   Typedef for the configuration version number.
+ */
+typedef uint8_t config_version_t;
+
 /* ----------------------------------------------------- MACROS ----------------------------------------------------- */
 
 /**
@@ -74,6 +80,12 @@ typedef struct
  */
 void config_default( config_t * config );
 
+/**
+ * @fn      config_flush( void )
+ * @brief   Immediately writes the current configuration to storage.
+ */
+void config_flush( void );
+
 /**
  * @fn      config_get( config_t * )
  * @brief   Copies the current application configuration into the specified struct.
@@ -100,4 +112,10 @@ config_t const * config_read_only( void );
  */
 bool config_set( config_t const * config );
 
+/**
+ * @fn      config_tick( tick_t )
+ * @brief   Performs periodic processing at the specified tick.
+ */
+void config_tick( tick_t tick );
+
 #endif /* !defined( APPLICATION_CONFIG_H ) */