//On PIC18 devices, addresses 0x00, 0x08, and 0x18 are used for
//the reset, high priority interrupt, and low priority interrupt
//vectors. However, the current Microchip USB bootloader
//examples are intended to occupy addresses 0x00-0x7FF or
//0x00-0xFFF depending on which bootloader is used. Therefore,
//the bootloader code remaps these vectors to new locations
//as indicated below. This remapping is only necessary if you
//wish to program the hex file generated from this project with
//the USB bootloader. If no bootloader is used, edit the
//usb_config.h file and comment out the following defines:
//#define PROGRAMMABLE_WITH_USB_HID_BOOTLOADER
//#define PROGRAMMABLE_WITH_USB_LEGACY_CUSTOM_CLASS_BOOTLOADER
#if defined(PROGRAMMABLE_WITH_USB_HID_BOOTLOADER)
#define REMAPPED_RESET_VECTOR_ADDRESS 0x1000
#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x1008
#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x1018
#elif defined(PROGRAMMABLE_WITH_USB_MCHPUSB_BOOTLOADER)
#define REMAPPED_RESET_VECTOR_ADDRESS 0x800
#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x808
#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x818
#else
#define REMAPPED_RESET_VECTOR_ADDRESS 0x00
#define REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS 0x08
#define REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS 0x18
#endif
#if defined(PROGRAMMABLE_WITH_USB_HID_BOOTLOADER)||defined(PROGRAMMABLE_WITH_USB_MCHPUSB_BOOTLOADER)
extern void _startup (void); // See c018i.c in your C18 compiler dir
#pragma code REMAPPED_RESET_VECTOR = REMAPPED_RESET_VECTOR_ADDRESS
void _reset (void)
{
_asm goto _startup _endasm
}
#endif
#pragma code REMAPPED_HIGH_INTERRUPT_VECTOR = REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS
void Remapped_High_ISR (void)
{
_asm goto YourHighPriorityISRCode _endasm
}
#pragma code REMAPPED_LOW_INTERRUPT_VECTOR = REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS
void Remapped_Low_ISR (void)
{
_asm goto YourLowPriorityISRCode _endasm
}
#if defined(PROGRAMMABLE_WITH_USB_HID_BOOTLOADER)||defined(PROGRAMMABLE_WITH_USB_MCHPUSB_BOOTLOADER)
//Note: If this project is built while one of the bootloaders has
//been defined, but then the output hex file is not programmed with
//the bootloader, addresses 0x08 and 0x18 would end up programmed with 0xFFFF.
//As a result, if an actual interrupt was enabled and occured, the PC would jump
//to 0x08 (or 0x18) and would begin executing "0xFFFF" (unprogrammed space). This
//executes as nop instructions, but the PC would eventually reach the REMAPPED_RESET_VECTOR_ADDRESS
//(0x1000 or 0x800, depending upon bootloader), and would execute the "goto _startup". This
//would effective reset the application.
//To fix this situation, we should always deliberately place a
//"goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS" at address 0x08, and a
//"goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS" at address 0x18. When the output
//hex file of this project is programmed with the bootloader, these sections do not
//get bootloaded (as they overlap the bootloader space). If the output hex file is not
//programmed using the bootloader, then the below goto instructions do get programmed,
//and the hex file still works like normal. The below section is only required to fix this
//scenario.
#pragma code HIGH_INTERRUPT_VECTOR = 0x08
void High_ISR (void)
{
_asm goto REMAPPED_HIGH_INTERRUPT_VECTOR_ADDRESS _endasm
}
#pragma code LOW_INTERRUPT_VECTOR = 0x18
void Low_ISR (void)
{
_asm goto REMAPPED_LOW_INTERRUPT_VECTOR_ADDRESS _endasm
}
#endif //end of "#if defined(PROGRAMMABLE_WITH_USB_HID_BOOTLOADER)||defined(PROGRAMMABLE_WITH_USB_LEGACY_CUSTOM_CLASS_BOOTLOADER)"
#pragma code
//These are your actual interrupt handling routines.
#pragma interrupt YourHighPriorityISRCode
void YourHighPriorityISRCode()
{
//Check which interrupt flag caused the interrupt.
//Service the interrupt
//Clear the interrupt flag
//Etc.
} //This return will be a "retfie fast", since this is in a #pragma interrupt section
#pragma interruptlow YourLowPriorityISRCode
void YourLowPriorityISRCode()
{
//Check which interrupt flag caused the interrupt.
//Service the interrupt
//Clear the interrupt flag
//Etc.
} //This return will be a "retfie", since this is in a #pragma interruptlow section
