Bootloader.c

#include <xc.h>
#include"pic16f877"
#include <stdint.h>

// Configuration settings for the PIC16F887 (modify as needed)
__CONFIG(FOSC_HS & WDTE_OFF & PWRTE_OFF & CP_OFF);

// UART communication settings
#define UART_BAUDRATE 9600
#define UART_TX_PIN   TRISC6
#define UART_RX_PIN   TRISC7

// Define memory addresses for firmware update area
#define BOOTLOADER_START_ADDRESS 0x2000 // This is just a placeholder
#define APPLICATION_START_ADDRESS 0x0000 // This is the starting address of your application

void main() {
    // Check if a firmware update is requested (e.g., based on an external condition)
    if (firmwareUpdateRequested()) {
        // Execute firmware update process
        firmwareUpdate();
    } else {
        // Jump to the application if no update is requested
        gotoApplication();
    }
}

// Function to check if a firmware update is requested (e.g., through a button press or external signal)
int firmwareUpdateRequested() {
    // Implement your logic here
    return 0;
}

// Function to perform the firmware update
void firmwareUpdate() {
    // Implement the update process, which involves receiving new firmware data and writing it to the application area
// Function to initialize UART communication
void UART_Initialize() {
    SPBRG = (unsigned char)((_XTAL_FREQ / (16 * UART_BAUDRATE)) - 1);
    TXSTAbits.SYNC = 0;
    TXSTAbits.BRGH = 1;
    RCSTAbits.SPEN = 1;
    TXSTAbits.TXEN = 1;
    RCSTAbits.CREN = 1;
}


    // Wait for incoming firmware data
    while (1) {
        receiveAndWriteFirmware();
    
}

    // After updating, reset the microcontroller or jump to the application
    resetMicrocontroller();
}

// Function to receive and write firmware data
void receiveAndWriteFirmware() {
    // Implement firmware reception and writing logic here
// Function to write firmware data to Flash memory
void writeFirmwareToFlash(uint16_t address, uint8_t* data, uint16_t length) {
    // Unlock the Flash memory for writing
    INTCONbits.GIE = 0; // Disable interrupts
    EECON2 = 0x55;
    EECON2 = 0xAA;
    EECON1bits.WR = 1; // Start the write operation
    INTCONbits.GIE = 1; // Re-enable interrupts

    // Wait for the write operation to complete
    while (EECON1bits.WR)
        ;

    // Copy the firmware data to the specified Flash memory address
    for (uint16_t i = 0; i < length; i++) {
        asm("DISI #5"); // Disable interrupts during write
        TBLPTR = address + i;
        TABLAT = data[i];
        asm("TBLWTPOSTINC"); // Write to Flash and post-increment address
    }

    // Write the buffer to Flash
    asm("DISI #5");
    EECON1 = 0x04; // Load control register for Write
    asm("DISI #5");
    asm("MOVLW 0x55");
    asm("MOVWF EECON2");
    asm("DISI #5");
    asm("MOVLW 0xAA");
    asm("MOVWF EECON2");
    asm("DISI #5");
    EECON1bits.WR = 1; // Start the write operation

    // Wait for the write operation to complete
    while (EECON1bits.WR)
        ;
}

// Function to receive and write firmware data
void receiveAndWriteFirmware() {
    uint8_t receivedData[64]; // Buffer for receiving firmware data
    uint16_t firmwareAddress = 0x2000; // Start address in Flash memory
    uint16_t dataIndex = 0;
    uint8_t receivedByte;

    // Implement UART receive logic
    // Wait for the start of a firmware update packet (e.g., a special header or synchronization sequence)

    while (1) {
        // Receive data over UART
        // For example, you might use a function like UART_ReadByte() to receive a byte
        // Implement your own logic for reading data from the UART

        receivedByte = UART_ReadByte(); // Replace with your UART receive function

        // Check for the end of the firmware data
        if (receivedByte == 0xFF) {
            break;
        }

        // Store received data in the buffer
        receivedData[dataIndex] = receivedByte;
        dataIndex++;

        // If the buffer is full, write the data to Flash memory and reset the index
        if (dataIndex == sizeof(receivedData)) {
            writeFirmwareToFlash(firmwareAddress, receivedData, sizeof(receivedData));
            firmwareAddress += sizeof(receivedData);
            dataIndex = 0;
        }
    }

    // Write any remaining data to Flash memory
    if (dataIndex > 0) {
        writeFirmwareToFlash(firmwareAddress, receivedData, dataIndex);
    }
}


}

// Function to jump to the application code
void gotoApplication() {
    asm("GOTO " _STR(APPLICATION_START_ADDRESS));
}

// Function to reset the microcontroller
void resetMicrocontroller() {
    asm("RESET");
}

void interrupt high_priority HighIsr(void) {
    // Implement your interrupt handling code here
}

void interrupt low_priority LowIsr(void) {
    // Implement your interrupt handling code here
}