bia_microddr_fw/bootloader/src/main.c

/*
 * File:   main.c
 * Author: justin
 *
 * Created on August 9, 2019, 6:14 PM
 */

#include <xc.h>
#include "usb.h"
#include "bootloader.h"

/* Private prototypes */
void main(void);
void BootMain(void);

const unsigned int FlashSignatureWord __at(APP_SIGNATURE_ADDRESS) = APP_SIGNATURE_VALUE;

void main(void)
{
    //BootMain();
    /**
     * TODO: implement hardware IO-based method for forcing entry into bootloader
     */
    
    // normal operation: verify the firmware signature is valid. if it isn't enter
    // bootloader (fw update) mode so valid firmware can be flashed
//DoFlashSignatureCheck:
    //Check if the application region flash signature is valid
    if(*(const 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(*(const unsigned int*)REMAPPED_APPLICATION_RESET_VECTOR != 0xFFFF)
        {
            //Go ahead and jump out of bootloader mode into the application run mode
            #asm
                goto REMAPPED_APPLICATION_RESET_VECTOR
            #endasm
        }
    }
    //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.
    
    BootMain();
}

void BootMain(void) __at(0x30)
{
    //Make sure interrupts are disabled for this code (could still be on,
    //if the application firmware jumped into the bootloader via software methods)
    INTCON = 0x00;

    //Clear the stack pointer, in case the user application jumped into 
    //bootloader mode with excessive junk on the call stack
    STKPTR = 0x00;  

    // End of the important parts of the C initializer.  This bootloader firmware does not use
    // any C initialized user variables (idata memory sections).  Therefore, the above is all
    // the initialization that is required.

    // initialize the USB framework
    USBDeviceInit();
    USBDeviceAttach();
    
    // initialize the bootloader
    UserInit();
    
    //Execute main loop
    while(1)
    {
        //Need to call USBDeviceTasks() periodically.  This function takes care of
        //processing non-USB application related USB packets (ex: "Chapter 9" 
        //packets associated with USB enumeration)
        USBDeviceTasks();
        
        ProcessIO();        //This is where all the actual bootloader related data transfer/self programming takes
                            //place see ProcessIO() function in the BootPIC[xxxx].c file.
    }//end while    
}