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FlashIAPBlockDevice

FlashIAPBlockDevice class hierarchy

The flash IAP block device is a block device driver built on top of the FlashIAP API. This is enabled using the internal flash memory as a block device. The read size, write size and erase size may differ, depending on the flash chip. Use the FlashIAPBlockDevice get function to discover those sizes.

Additional notes:

  1. Use this driver on platforms where the FlashIAP implementation uses external flash or in conjunction with a file system with wear leveling, that can operate on a page size granularity.
  2. The FlashIAP may freeze code execution for a long period of time while writing to flash. Not even high-priority IRQs are allowed to run, which may interrupt background processes.

To configure this class, please see our BlockDevice configuration documentation.

FlashIAPBlockDevice class reference

Public Member Functions
 FlashIAPBlockDevice (uint32_t address=MBED_CONF_FLASHIAP_BLOCK_DEVICE_BASE_ADDRESS, uint32_t size=MBED_CONF_FLASHIAP_BLOCK_DEVICE_SIZE)
 Creates a FlashIAPBlockDevice. More...
virtual int init ()
 Initialize a block device. More...
virtual int deinit ()
 Deinitialize a block device. More...
virtual int read (void *buffer, mbed::bd_addr_t addr, mbed::bd_size_t size)
 Read blocks from a block device. More...
virtual int program (const void *buffer, mbed::bd_addr_t addr, mbed::bd_size_t size)
 Program blocks to a block device. More...
virtual int erase (mbed::bd_addr_t addr, mbed::bd_size_t size)
 Erase blocks on a block device. More...
virtual mbed::bd_size_t get_read_size () const
 Get the size of a readable block. More...
virtual mbed::bd_size_t get_program_size () const
 Get the size of a programable block. More...
virtual mbed::bd_size_t get_erase_size () const
 Get the size of a eraseable block. More...
virtual mbed::bd_size_t get_erase_size (mbed::bd_addr_t addr) const
 Get the size of an erasable block given address. More...
virtual int get_erase_value () const
 Get the value of storage when erased. More...
virtual mbed::bd_size_t size () const
 Get the total size of the underlying device. More...
virtual const char * get_type () const
 Get the BlockDevice class type. More...
virtual int sync ()
 Ensure data on storage is in sync with the driver. More...
virtual int trim (bd_addr_t addr, bd_size_t size)
 Mark blocks as no longer in use. More...
bool is_valid_read (bd_addr_t addr, bd_size_t size) const
 Convenience function for checking block read validity. More...
bool is_valid_program (bd_addr_t addr, bd_size_t size) const
 Convenience function for checking block program validity. More...
bool is_valid_erase (bd_addr_t addr, bd_size_t size) const
 Convenience function for checking block erase validity. More...
Static Public Member Functions
static BlockDeviceget_default_instance ()
 Return the default block device. More...

FlashIAPBlockDevicesBlockDevice example:

#include "mbed.h"
#include "FlashIAPBlockDevice.h"

// Create flash IAP block device
FlashIAPBlockDevice bd;

int main() {
    printf("FlashIAPBlockDevice test\n");

    // Initialize the flash IAP block device and print the memory layout
    bd.init();
    printf("Flash block device size: %llu\n",         bd.size());
    printf("Flash block device read size: %llu\n",    bd.get_read_size());
    printf("Flash block device program size: %llu\n", bd.get_program_size());
    printf("Flash block device erase size: %llu\n",   bd.get_erase_size());

    // Write "Hello World!" to the first block
    char *buffer = (char*)malloc(bd.get_erase_size());
    sprintf(buffer, "Hello World!\n");
    bd.erase(0, bd.get_erase_size());
    bd.program(buffer, 0, bd.get_erase_size());

    // Read back what was stored
    bd.read(buffer, 0, bd.get_erase_size());
    printf("%s", buffer);

    // Deinitialize the device
    bd.deinit();
}

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