Renamed and moved FLASH_PAGE_SIZE; added compile-time check

rtl837x_flash.h

@@ -1,8 +1,16 @@
 #ifndef _RTL837X_FLASH_H_
 #define _RTL837X_FLASH_H_
 
+// SPI FLASH MEMORY PAGE SIZE.
+#define FLASH_PAGE_SIZE 0x100
+// SPI FLASH MEMORY SECTOR SIZE = ERASE SIZE.
 #define FLASH_SECTOR_SIZE 0x1000
 
+#if (FLASH_SECTOR_SIZE % FLASH_PAGE_SIZE) != 0
+#error "FLASH_SECTOR_SIZE must be a multiple of FLASH_PAGE_SIZE"
+#endif
+
+
 void flash_init(uint8_t enable_dio);
 void flash_read_uid(void);
 void flash_write_enable(void);