AT90USB128X Просмотр технического описания (PDF) - Atmel Corporation

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AT90USB128X

USB DFU Bootloader Datasheet

Atmel Corporation 

The API are located at absolute addresses in the USB bootloader firmware and accept specific

registers values as parameters. These parameters are compatible with a C compiler calling con-

vention and thus can be called directly with function pointer declared as in the example below:

C Code Example

#if (FLASH_END==0x1FFFF) //128K bytes parts

#define LAST_BOOT_ENTRY 0xFFFE

#elif (FLASH_END==0xFFFF)//64K bytes parts

#define LAST_BOOT_ENTRY 0x7FFE

#else

#error You must define FLASH_END in bytes.

#endif

// These functions pointers are used to call functions entry points in bootloader

void (*boot_flash_page_erase_and_write)(unsigned long adr)=(void (*)(unsigned

long))(LAST_BOOT_ENTRY-12);

U8 (*boot_flash_read_sig) (unsigned long adr)=(U8 (*)(unsigned

long))(LAST_BOOT_ENTRY-10);

U8 (*boot_flash_read_fuse) (unsigned long adr)=(U8 (*)(unsigned

long))(LAST_BOOT_ENTRY-8);

void (*boot_flash_fill_temp_buffer) (unsigned int data,unsigned int adr)=(void

(*)(unsigned int, unsigned int))(LAST_BOOT_ENTRY-6);

void (*boot_flash_prg_page) (unsigned long adr)=(void (*)(unsigned

long))(LAST_BOOT_ENTRY-4);

void (*boot_flash_page_erase) (unsigned long adr)=(void (*)(unsigned

long))(LAST_BOOT_ENTRY-2);

void (*boot_lock_wr_bits) (unsigned char val)=(void (*)(unsigned

char))(LAST_BOOT_ENTRY);

// This function writes 0x55AA @ 0x1200 in the on-flash calling flash drivers located

in USB bootloader

void basic_flash_access(void)

{

unsigned long address;

unsigned int temp16;

temp16=0x55AA;

address=0x12000;

(*boot_flash_fill_temp_buffer)(temp16,address);

(*boot_flash_page_erase)(address);

(*boot_flash_prg_page)(address);

}

The full assembly code for the flash API drivers is given in “Appendix-B” on page 20.

16

7618C–AVR–07/08

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