Flash IAP

The flash in application programming provides an interface for access to MCU internal flash memory.

Flash IAP devices have different sized blocks for different operations. They allow you to read and program in defined-sized pages, but you must erase them in defined-sized sectors. The sector size must be a multiple of the page size. Sector sizes can differ within a device.

Flash IAP provides the following functionality:

  • Read from a flash device.
  • Program data to flash device pages.
  • Erase flash device sectors.
  • Get sector/flash or page sizes.
  • Get the start address of the flash device.

Flash devices have some requirements and limitations based on the operation. Please read the documentation for each operation.

Be aware that Flash IAP might disable interrupts for a long time. This can affect the application latency.

This class is thread-safe.

API

View the full C++ API:

 
 /* mbed Microcontroller Library
  * Copyright (c) 2017 ARM Limited
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
 #ifndef MBED_FLASHIAP_H
 #define MBED_FLASHIAP_H
 
 #if defined (DEVICE_FLASH) || defined(DOXYGEN_ONLY)
 
 #include "flash_api.h"
 #include "platform/SingletonPtr.h"
 #include "platform/PlatformMutex.h"
 
 namespace mbed {
 
 /** \addtogroup drivers */
 
 /** Flash IAP driver. It invokes flash HAL functions.
  *
  * @note Synchronization level: Thread safe
  * @ingroup drivers
  */
 class FlashIAP {
 public:
  FlashIAP();
  ~FlashIAP();
 
  /** Initialize a flash IAP device
  *
  * Should be called once per lifetime of the object.
  * @return 0 on success or a negative error code on failure
  */
  int init();
 
  /** Deinitialize a flash IAP device
  *
  * @return 0 on success or a negative error code on failure
  */
  int deinit();
 
  /** Read data from a flash device.
  *
  * This method invokes memcpy - reads number of bytes from the address
  *
  * @param buffer Buffer to write to
  * @param addr Flash address to begin reading from
  * @param size Size to read in bytes
  * @return 0 on success, negative error code on failure
  */
  int read(void *buffer, uint32_t addr, uint32_t size);
 
  /** Program data to pages
  *
  * The sectors must have been erased prior to being programmed
  *
  * @param buffer Buffer of data to be written
  * @param addr Address of a page to begin writing to, must be a multiple of program and sector sizes
  * @param size Size to write in bytes, must be a multiple of program and sector sizes
  * @return 0 on success, negative error code on failure
  */
  int program(const void *buffer, uint32_t addr, uint32_t size);
 
  /** Erase sectors
  *
  * The state of an erased sector is undefined until it has been programmed
  *
  * @param addr Address of a sector to begin erasing, must be a multiple of the sector size
  * @param size Size to erase in bytes, must be a multiple of the sector size
  * @return 0 on success, negative error code on failure
  */
  int erase(uint32_t addr, uint32_t size);
 
  /** Get the sector size at the defined address
  *
  * Sector size might differ at address ranges.
  * An example <0-0x1000, sector size=1024; 0x10000-0x20000, size=2048>
  *
  * @param addr Address of or inside the sector to query
  * @return Size of a sector in bytes or MBED_FLASH_INVALID_SIZE if not mapped
  */
  uint32_t get_sector_size(uint32_t addr) const;
 
  /** Get the flash start address
  *
  * @return Flash start address
  */
  uint32_t get_flash_start() const;
 
  /** Get the flash size
  *
  * @return Flash size
  */
  uint32_t get_flash_size() const;
 
  /** Get the program page size
  *
  * @return Size of a program page in bytes
  */
  uint32_t get_page_size() const;
 
 private:
 
  /* Check if address and size are aligned to a sector
  *
  * @param addr Address of block to check for alignment
  * @param size Size of block to check for alignment
  * @return true if the block is sector aligned, false otherwise
  */
  bool is_aligned_to_sector(uint32_t addr, uint32_t size);
 
  flash_t _flash;
  static SingletonPtr<PlatformMutex> _mutex;
 };
 
 } /* namespace mbed */
 
 #endif /* DEVICE_FLASH */
 
 #endif /* MBED_FLASHIAP_H */
Definition: FlashIAP.h:40
uint32_t get_page_size() const
uint32_t get_flash_size() const
int erase(uint32_t addr, uint32_t size)
uint32_t get_flash_start() const
uint32_t get_sector_size(uint32_t addr) const
int read(void *buffer, uint32_t addr, uint32_t size)
Definition: AnalogIn.h:27
int program(const void *buffer, uint32_t addr, uint32_t size)

Example

For an example that uses the FlashIAP driver, please see the bootloader example.