update code base to Marlin 2.0.9.2

Marlin/src/gcode/eeprom/M500-M504.cpp

@@ -16,12 +16,12 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
 
 #include "../gcode.h"
-#include "../../module/configuration_store.h"
+#include "../../module/settings.h"
 #include "../../core/serial.h"
 #include "../../inc/MarlinConfig.h"
 
@@ -58,11 +58,47 @@ void GcodeSuite::M502() {
 #endif // !DISABLE_M503
 
 #if ENABLED(EEPROM_SETTINGS)
+
+  #if ENABLED(MARLIN_DEV_MODE)
+    #include "../../libs/hex_print.h"
+  #endif
+
   /**
    * M504: Validate EEPROM Contents
    */
   void GcodeSuite::M504() {
+    #if ENABLED(MARLIN_DEV_MODE)
+      const bool dowrite = parser.seenval('W');
+      if (dowrite || parser.seenval('R')) {
+        uint8_t val = 0;
+        int addr = parser.value_ushort();
+        if (dowrite) {
+          val = parser.byteval('V');
+          persistentStore.write_data(addr, &val);
+          SERIAL_ECHOLNPGM("Wrote address ", addr, " with ", val);
+        }
+        else {
+          if (parser.seenval('T')) {
+            const int endaddr = parser.value_ushort();
+            while (addr <= endaddr) {
+              persistentStore.read_data(addr, &val);
+              SERIAL_ECHOLNPGM("0x", hex_word(addr), ":", hex_byte(val));
+              addr++;
+              safe_delay(10);
+            }
+            SERIAL_EOL();
+          }
+          else {
+            persistentStore.read_data(addr, &val);
+            SERIAL_ECHOLNPGM("Read address ", addr, " and got ", val);
+          }
+        }
+        return;
+      }
+    #endif
+
     if (settings.validate())
       SERIAL_ECHO_MSG("EEPROM OK");
   }
+
 #endif