/* * 18Fxxx BOOT LOADER Copyright (C) 2002 HI-TECH Software *	This software is freely distributable and may be used *	for any purpose. No warranty of any kind is provided *	and all use is entirely at your own risk. *	 */#pragma psect text=bootldr #include <pic18.h>#include "bootldr.h"#if defined(MPLAB_ICD)__CONFIG(4,DEBUGEN & LVPDIS);	// required ICD2 settings__CONFIG(6,UNPROTECT);		// enable writing to flash#else__CONFIG(6,WPB & UNPROTECT);	// bootloader self protection#endif#if _ERRATA_TYPES & ERRATA_4000  #error Command line option --errata=default,-4000 must be specified when compiling this code for this device.#endif/* Function prototypes */void checksum(void);void putch(unsigned char);void puts(const char *s);unsigned char gx(void);unsigned char g2x(void);void zap(void);void table_write(void);void flash8(void);void clear_buffer(void);persistent near unsigned char buff[_FLASH_WRITE_SIZE];	/* Internal buffer used for writing to program memory */persistent near unsigned char DO_NOT_INCREMENT;persistent near unsigned char cksum,rectype,bcount;persistent near unsigned char delay_time;persistent near unsigned char index;persistent near unsigned short erase;#ifdef VERBOSEpersistent near unsigned char START_MSG[] = "HI-TECH Software (C)2002\n";persistent near unsigned char DOWNLOAD_MSG[] = "\rDownload-";#endif#asmpsect intcode	// redirect interrupts to new routine addresses	goto	PROG_START+8	#ifndef VERBOSE/* Sqeeze the checksum function in between the ISR redirection * instructions for even tighter code! * Will not fit if VERBOSE mode is enabled, in which case * the C version will be used. */global _checksum_checksum:	call	_g2x		// read the checksum byte	movf	_cksum,w	btfss	status,2,c	// if it doesn't add up...	reset			// reset	return#endif	psect intcodelo	// redirect low priority interrupts to new routine addresses	goto	PROG_START+0x18#endasm/* putch() - outputs 1 byte to the serial port */#ifdef VERBOSEvoidputch(unsigned char byte){	while(!TRMT);	/* set when register is empty */	TXREG = byte;	/* output one byte */}/* Output a string via the serial port */voidputs(const char *s){		while(s && *s)				putch(*s++);	}/* check the checksum  * NOTE: if not in verbose mode, the code will use the even more compact * assembler version of the checksum() function defined above. */voidchecksum(void){	g2x();	if(cksum)	// if checksum does not add to zero, bad check, reset		RESET();	putch('\r');	// echo each hex record on a new line}	#endif/* Get a 4 bit HEX number from the serial port */unsigned chargx(void){	while(!RCIF);	EEDATA=RCREG;#ifdef VERBOSE	if(!TRMT)		// Echo RX nibbles to output. If high speed RX, some 		TXREG=EEDATA;	// nibbles mightn't be TXed but will still be programmed.#endif	if(EEDATA>='A')		return ((EEDATA - (unsigned char)'A')+10);	return (EEDATA - '0');}/* recieve a hexadecimal byte, add it to the checksum */unsigned char g2x(void){	unsigned char temp = (gx()<<4);	temp += gx();	cksum+=temp;	return temp;}/* Initiate a write to memory */voidzap(void){	WREN=1;	EECON2=0x55;	EECON2=0xAA;	WR=1;	NOP();	while(WR);	WREN=0;}/* transfer a byte from RAM to internal flash register(s) */voidtable_write(void){	if(DO_NOT_INCREMENT)	// address is already loaded in TBLPTR, no pre-increment needed		asm("tblwt*");	else		asm("tblwt+*");	// otherwise TBLPTR must be pre-incremented	DO_NOT_INCREMENT=0;}/* Commit the internal buffer to flash */voidflash8(void){	if(DO_NOT_INCREMENT)		TBLPTRL&= ~(_FLASH_WRITE_SIZE-1);	// point to start of flash panel	for(index=0;index<_FLASH_WRITE_SIZE;)	{			TABLAT = buff[index++];		table_write();	}	zap();}voidclear_buffer(void){	unsigned char x;	for(x=sizeof(buff);x--;){		buff[x]=FILL_BYTE;	// initialize buffer with known values	}}voidmain(void){#if _ERRATA_TYPES & ERRATA_TBLWTINT 	PIE1=0;	// as per the errata document for these parts#endif	init_comms();	// sets up the serial port for communication/* Bootloader waits for a specified time. If the serial port gets no response in *//* this time, execution of existing program begins. */#ifdef VERBOSE	puts(START_MSG);#else	TXREG='\n';#endif	// Some devices' errata require these registers to be cleared	INTCON3=0;	// Also serves to disable interrupts	PIE2=0;	INTCON=0;	T0CON = 0x94;	// use timer to give ~1 second delays	for(delay_time=BOOT_TIMEOUT; delay_time ; --delay_time)	{		if (RCIF)			break;#ifdef VERBOSE	/* display a countdown for user response */		puts(DOWNLOAD_MSG);		putch('0'+delay_time);#else		TXREG=('0'+delay_time);		while(!TRMT);		TXREG='\r';#endif		while(!TMR0IF);	// pause for timer 0 timeout		TMR0IF=0;	}	T0CON=0xFF;	// disable timer again	if (!RCIF)	/* if no hex file to download, resume normal program */	{		(*((void(*)(void))PROG_START))();	}	TXREG=':';	// the prompt to invite you to download a new program	TBLPTRU=0;	erase=PROG_START;	/* Clear program memory prior to program download */	while(1)	{		TBLPTRL=(unsigned char)erase;		TBLPTRH=(unsigned char)(erase>>8);		EECON1=0x90;	// set up for flash erasure		zap();		erase+=_FLASH_ERASE_SIZE;#if defined(UPPER_ADDRESS_BYTE)	// cases where top of memory greater than 10000h		if(erase==0)			TBLPTRU++;		if(TBLPTRU==UPPER_ADDRESS_BYTE)	// continues to next "if" or "break"#endif#if !defined(UPPER_ADDRESS_BYTE) || (MEM_TOP!=0)		if(erase==MEM_TOP)	// for MEM_TOPs like 20000h, don't need to test lower 0000h#endif			break;	}#ifdef UPPER_ADDRESS_BYTE	TBLPTRU=0;#endif/* receive a hex file via the serial port and write it to program memory */	for(;;)		// loop until end of file	{		while (RCREG!=':');		// wait for start of hex file line #ifdef VERBOSE		putch(':');#endif				cksum = bcount = g2x();		// get the byte count #if _EEPROMSIZE > 256		EEADRH = TBLPTRH = g2x();		// get the address#else		TBLPTRH = g2x();#endif		TBLPTRL = EEADR = g2x();				DO_NOT_INCREMENT = 1;		rectype = g2x();	// get the record type 				switch(rectype)		{			case DATA:	// data record #if (PROG_START > 0x200) || defined(__PIC18FX520)	// to protect bootloader from being overwritten				if( (FLASH) && (TBLPTRU==0) && (TBLPTRH < (unsigned char)(PROG_START>>8)) )	// to protect bootloader from being overwritten					break;		// if bootloader address range is threatened, skip this record#endif			clear_buffer();				while(bcount--)				{						TABLAT = EEDATA = buff[(EEADR&(_FLASH_WRITE_SIZE-1))] = g2x();	// get the data					if((CONFIG)||(EEPROM))					{						if(CONFIG)	// EEPROM/config. bytes are written one byte at a time							table_write();						zap();					}					else						if((EEADR & (_FLASH_WRITE_SIZE-1)) == (_FLASH_WRITE_SIZE-1))	// program/IDLOCs are flashed x bytes at a time						{							flash8();							clear_buffer();						}					EEADR++;				}					if(((EEADR&(_FLASH_WRITE_SIZE-1))!=0)&&(FLASH))                                        flash8();				checksum();				break;			case END:	// end of hex file				checksum();				TXREG=')';				(*((void(*)(void))PROG_START))(); // jump to new program 				break;			case EXTEND_ADDRESS:	// extended address record				while(bcount--)				{					EEADR=g2x();	// this byte determines whether EE, Config or ID data				}								EEPGD=1;				if(EEADR==0xF0)					EEPGD=0;	// select for EEPROM									CFGS=0;				if((EEADR&0xF0)==0x30)					CFGS=1;		// select for config write									TBLPTRU=EEADR;				checksum();				break;		}	}}