start_boot.h File Reference

This file contains the routines to jump in ISP mode. More...

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Defines
#define	GOTOBOOTKEY   0x55AAAA55
Functions
void	start_boot (void)
	This function will start the on-chip bootloader after a watchdog timer reset.
void	start_boot_if_required (void)
	This function calls the on-chip bootloader.
void	goto_boot (void)
	This function jump to on-chip bootloader without CPU reset.
Variables
__no_init U32	boot_key

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Detailed Description

This file contains the routines to jump in ISP mode.

• Compiler: IAR EWAVR and GNU GCC for AVR
• Supported devices: ATmega32U4

Author:

Atmel Corporation: http://www.atmel.com
Support and FAQ: http://support.atmel.no/

Definition in file start_boot.h.

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Define Documentation

#define GOTOBOOTKEY   0x55AAAA55

Definition at line 47 of file start_boot.h.

Referenced by start_boot_if_required().

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Function Documentation

void start_boot

(

void

)

This function will start the on-chip bootloader after a watchdog timer reset.

The function set a special key in sram (uninitialized during mcu start-up execution) and performs a mcu watchdog timer reset. This function should be called when a special eve,t is detected in the application that requires the bootloader activation. When this function is used, be sure to implement the "start_boot_if_required()" function at the begining of main().

Definition at line 82 of file start_boot.c.

References boot_key, wdtdrv_enable(), and WDTO_500MS.

{
   boot_key=0x55AAAA55;
   
   // Enable the WDT for reset mode
   wdtdrv_enable(WDTO_500MS);
   while(1);
}

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void start_boot_if_required

(

void

)

This function calls the on-chip bootloader.

The function starts the on-chip bootloader if the application has posted such a request. This function sould be inserted at the begining of the main function.

Jumping to bootloader

Definition at line 97 of file start_boot.c.

References boot_key, and GOTOBOOTKEY.

Referenced by main().

{
  if(boot_key==GOTOBOOTKEY)
  {
      boot_key = 0;
      (*start_bootloader)();           
  }
}

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void goto_boot

(

void

)

This function jump to on-chip bootloader without CPU reset.

Jumping to bootloader

Definition at line 109 of file start_boot.c.

{
   (*start_bootloader)();              
}

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Variable Documentation

__no_init U32 boot_key

Referenced by start_boot(), and start_boot_if_required().