/******************************************************************************
* Function: void main(void)
*
* PreCondition: None
*
* Input: None
*
* Output: None
*
* Side Effects: None
*
* Overview: This is the first code that executes during boot up of
* the microcontroller. This code checks to see if execution
* should stay in the "bootloader" mode, or if it should jump
* into the "application" (non-bootloder) execution mode.
* No other unrelated code should be added to this function.
*
* Note: THIS FUNCTION EXECUTES PRIOR TO INITIALIZATION OF THE C
* STACK. NO C INITIALIZATION OF STATIC VARIABLES OR RESOURCES
* WILL OCCUR, PRIOR TO EXECUTING THIS FUNCTION. THEREFORE,
* THE CODE IN THIS FUNCTION MUST NOT CALL OTHER FUNCTIONS OR
* PERFORM ANY OPERATIONS THAT WILL REQUIRE C INITIALIZED
* BEHAVIOR.
*****************************************************************************/
void main(void)
{
//Assuming the I/O pin check entry method is enabled, check the I/O pin value
//to see if we should stay in bootloader mode, or jump to normal applicaiton
//execution mode.
#ifdef ENABLE_IO_PIN_CHECK_BOOTLOADER_ENTRY
//Need to make sure the I/O pin is configured for digital mode so we
//can sense the digital level on the input pin.
mInitSwitch2();
//Check Bootload Mode Entry Condition from the I/O pin (ex: place a
//pushbutton and pull up resistor on the pin)
if(sw2 == 1)
{
//If we get to here, the user is not pressing the pushbutton. We
//should default to jumping into application run mode in this case.
//Restore default "reset" value of registers we may have modified temporarily.
mDeInitSwitch2();
//Before going to application image however, make sure the image
//is properly signed and is intact.
goto DoFlashSignatureCheck;
}
else
{
//User is pressing the pushbutton. We should stay in bootloader mode
BootMain();
}
#endif //#ifdef ENABLE_IO_PIN_CHECK_BOOTLOADER_ENTRY
DoFlashSignatureCheck:
//Check if the application region flash signature is valid
if(*(ROM unsigned int*)APP_SIGNATURE_ADDRESS == APP_SIGNATURE_VALUE)
{
//The flash signature was valid, implying the previous
//erase/program/verify operation was a success.
//Also make sure the first WORD of program memory in the app space
//is not blank, meaning there is an application image programmed into the device.
if(*(ROM unsigned int*)REMAPPED_APPLICATION_RESET_VECTOR != 0xFFFF)
{
//Go ahead and jump out of bootloader mode into the application run mode
#ifdef __XC8__
#asm
goto REMAPPED_APPLICATION_RESET_VECTOR
#endasm
#else //Must be C18 instead
_asm goto REMAPPED_APPLICATION_RESET_VECTOR _endasm
#endif
}
}
//else the application image is missing or corrupt. In this case, we
//need to stay in the bootloader mode, so the user has the ability to
//try (again) to re-program a valid application image into the device.
//We should stay in bootloader mode
BootMain();
}//end UninitializedMain
/******************************************************************************
* Function: void UninitializedMain(void)
*
* PreCondition: None
*
* Input: None
*
* Output: None
*
* Side Effects: None
*
* Overview: This is the first code that executes during boot up of
* the microcontroller. This code checks to see if execution
* should stay in the "bootloader" mode, or if it should jump
* into the "application" (non-bootloder) execution mode.
* No other unrelated code should be added to this function.
*
* Note: THIS FUNCTION EXECUTES PRIOR TO INITIALIZATION OF THE C
* STACK. NO C INITIALIZATION OF STATIC VARIABLES OR RESOURCES
* WILL OCCUR, PRIOR TO EXECUTING THIS FUNCTION. THEREFORE,
* THE CODE IN THIS FUNCTION MUST NOT CALL OTHER FUNCTIONS OR
* PERFORM ANY OPERATIONS THAT WILL REQUIRE C INITIALIZED
* BEHAVIOR.
*****************************************************************************/
void UninitializedMain(void)
{
//Assuming the I/O pin check entry method is enabled, check the I/O pin value
//to see if we should stay in bootloader mode, or jump to normal applicaiton
//execution mode.
#ifdef ENABLE_IO_PIN_CHECK_BOOTLOADER_ENTRY
//Need to make sure the I/O pin is configured for digital mode so we
//can sense the digital level on the input pin.
mInitSwitch2();
//Check Bootload Mode Entry Condition from the I/O pin (ex: place a
//pushbutton and pull up resistor on the pin)
if(sw2 == 1)
{
//If we get to here, the user is not pressing the pushbutton. We
//should default to jumping into application run mode in this case.
//Restore default "reset" value of registers we may have modified temporarily.
mDeInitSwitch2();
//Before going to application image however, make sure the image
//is properly signed and is intact.
goto DoFlashSignatureCheck;
}
else
{
//User is pressing the pushbutton. We should stay in bootloader mode
_asm goto BootMain _endasm
}
#endif //#ifdef ENABLE_IO_PIN_CHECK_BOOTLOADER_ENTRY
DoFlashSignatureCheck:
//Check if the application region flash signature is valid
#ifdef ENABLE_FLASH_SIGNATURE_VERIFICATION
if(*(rom unsigned int*)APP_SIGNATURE_ADDRESS == APP_SIGNATURE_VALUE)
{
//The flash signature was valid, implying the previous
//erase/program/verify operation was a success.
//Go ahead and jump out of bootloader mode into the application run mode
_asm goto REMAPPED_APPLICATION_RESET_VECTOR _endasm
}
