使用ATMEGA8A 自己制作ARDUINO全过程

手上多余一大堆Mega8,最近刚好在熟悉ISP，想自己做一批来测试，重新写了Bootload，把代码贴出来给大家自己做，只用了512个字节，使用0x1c00开始地址作为Bootload地址，开机进入Bootload，10秒钟重启一次，如有有代码自动进入用户程序。

先上代码：

include

#include

#include

#include

#include

//#include

//#define EEPROM 0

//FUCS FF D9 00 FF  0x1800

//FUCS FF DA 00 FF  0x1C00  OKOK

//#define F_CPU 16000000

/* We, Malmoitians, like slow interaction

 * therefore the slow baud rate ;-)

 */

//#define BAUD_RATE 9600

/* 6.000.000 is more or less 8 seconds at the

 * speed configured here

 */

//#define MAX_TIME_COUNT 6000000

#define MAX_TIME_COUNT (F_CPU>>1)

//#define MAX_TIME_COUNT_MORATORY 1600000

/* SW_MAJOR and MINOR needs to be updated from time to time to avoid warning message from AVR Studio */

#define HW_VER 0x02

#define SW_MAJOR 0x01

#define SW_MINOR 0x12

// AVR-GCC compiler compatibility

// avr-gcc compiler v3.1.x and older doesn't support outb() and inb()

//      if necessary, convert outb and inb to outp and inp

#ifndef outb

#define outb(sfr,val)  (_SFR_BYTE(sfr) = (val))

#endif

#ifndef inb

#define inb(sfr) _SFR_BYTE(sfr)

#endif

/* defines for future compatibility */

#ifndef cbi

#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))

#endif

#ifndef sbi

#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))

#endif

/* Adjust to suit whatever pin your hardware uses to enter the bootloader */

#define eeprom_rb(addr)   eeprom_read_byte ((uint8_t *)(addr))

#define eeprom_rw(addr)   eeprom_read_word ((uint16_t *)(addr))

#define eeprom_wb(addr, val)   eeprom_write_byte ((uint8_t *)(addr), (uint8_t)(val))

/* Onboard LED is connected to pin PB5 */

#define LED_DDR  DDRB

#define LED_PORT PORTB

#define LED_PIN  PIND

#define LED      PIND5

#define SIG1 0x1E // Yep, Atmel is the only manufacturer of AVR micros.  Single source :(

#define SIG2 0x93

#define SIG3 0x07

#define PAGE_SIZE 0x20U //32 words

void putch(char);

char getch(void);

void getNch(uint8_t);

void byte_response(uint8_t);

void nothing_response(void);

#if 1

union address_union {

  uint16_t word;

  uint8_t  byte[2];

} address;

union length_union {

  uint16_t word;

  uint8_t  byte[2];

} length;

#endif

//uint16_t length;

//uint16_t address;

struct flags_struct {

  unsigned eeprom : 1;

 //unsigned rampz  : 1;

} flags;

uint8_t buff[256];

//uint8_t address_high;

//uint8_t pagesz=0x80;

//uint8_t i;

//uint8_t bootuart0=0,bootuart1=0;

void (*app_start)(void) = 0x0000;

void putch(char ch)

{

  /* m8 */

  while (!(inb(UCSRA) & _BV(UDRE)));

  outb(UDR,ch);

}

char getch(void)

{

  /* m8 */

uint32_t count = 0;

  while(!(inb(UCSRA) & _BV(RXC))) {

/* HACKME:: here is a good place to count times*/

count++;

//putch('.');

if (count > MAX_TIME_COUNT){

putch('!');

app_start();

}

  }

  return (inb(UDR));

}

void getNch(uint8_t count)

{

  uint8_t i;

  for(i=0;i    /* m8 */

    //while(!(inb(UCSRA) & _BV(RXC)));

    //inb(UDR);

getch(); // need to handle time out

  }

}

void byte_response(uint8_t val)

{

  if (getch() ==0x20) {

    putch(0x14);

    putch(val);

    putch(0x10);

  }

}

void nothing_response(void)

{

  if (getch() == 0x20) {

    putch(0x14);

    putch(0x10);

  }

}

int main(void)

{

  uint8_t ch,ch2;

  uint16_t w;

  //cbi(BL_DDR,BL);

  //sbi(BL_PORT,BL);

  asm volatile("nopnt");

  /* check if flash is programmed already, if not start bootloader anyway */

  //if(pgm_read_byte_near(0x0000) != 0xFF) {

    /* check if bootloader pin is set low */

   // if(bit_is_set(BL_PIN,BL)) app_start();

  //}

  /* initialize UART(s) depending on CPU defined */

  /* m8 */

  UBRRH = (((F_CPU/BAUD_RATE)/16)-1)>>8; // set baud rate

  UBRRL = (((F_CPU/BAUD_RATE)/16)-1);

  UCSRB = (1<  UCSRC = (1<

  //UBRRL = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);

  //UBRRH = (F_CPU/(BAUD_RATE*16L)-1) >> 8;

  //UCSRA = 0x00;

  //UCSRC = 0x86;

  //UCSRB = _BV(TXEN)|_BV(RXEN);

  /* this was giving uisp problems, so I removed it; without it, the boot

     works on with uisp and avrdude on the mac (at least). */

  putch('');

  //uint32_t l;

  //uint32_t time_count;

  //time_count=0;

  /* set LED pin as output */

//  sbi(LED_DDR,LED);

// for (i = 0; i < 16; i++) {

// outb(LED_PORT, inb(LED_PORT) ^ _BV(LED));

// _delay_loop_2(0);

// }

//for (l=0; l<40000000; l++)

//outb(LED_PORT, inb(LED_PORT) ^= _BV(LED));

  /* flash onboard LED three times to signal entering of bootloader */

  //for(i=0; i<3; ++i) {

    //for(l=0; l<40000000; ++l);

   // sbi(LED_PORT,LED);

    //for(l=0; l<40000000; ++l);

    //

  //}

 /* see comment at previous call to putch() */

 //putch(''); // this line is needed for the synchronization of the programmer

//cbi(LED_PORT,LED); 

  /* forever */

  for (;;) {

 //sbi(LED_PORT,LED);

    //if((inb(UCSRA) & _BV(RXC))){

    /* get character from UART */

ch = getch();

/* A bunch of if...else if... gives smaller code than switch...case ! */

/* Hello is anyone home ? */ 

if((ch=='P')||(ch=='Q')||(ch=='R')||(ch=='0')) {

  nothing_response();

  if (ch=='Q')app_start();

}

/* Request programmer ID */

/* Not using PROGMEM string due to boot block in m128 being beyond 64kB boundry  */

/* Would need to selectively manipulate RAMPZ, and it's only 9 characters anyway so who cares.  */

else if(ch=='1') {

if (getch() == ' ') {

putch(0x14);

putch('A');

putch('V');

putch('R');

putch(' ');

putch('I');

putch('S');

putch('P');

putch(0x10);

  }

}

/* AVR ISP/STK500 board commands  DON'T CARE so default nothing_response */

else if(ch=='@') {

  ch2 = getch();

  if (ch2>0x85) getch();

  nothing_response();

}

/* AVR ISP/STK500 board requests */

else if(ch=='A') {

  ch2 = getch();

  if(ch2==0x80) byte_response(HW_VER); // Hardware version

  else if(ch2==0x81) byte_response(SW_MAJOR); // Software major version

  else if(ch2==0x82) byte_response(SW_MINOR); // Software minor version

  //else if(ch2==0x98) byte_response(0x03); // Unknown but seems to be required by avr studio 3.56

  else byte_response(0x00); // Covers various unnecessary responses we don't care about

}

/* Device Parameters  DON'T CARE, DEVICE IS FIXED  */

else if(ch=='B') {

  getNch(20);

  nothing_response();

}

/* Parallel programming stuff  DON'T CARE  */

else if(ch=='E') {

  getNch(5);

  nothing_response();

}

/* Universal SPI programming command, disabled.  Would be used for fuses and lock bits.  */

else if(ch=='V') {

  getNch(4);

  byte_response(00);

}

/* Write memory, length is big endian and is in bytes  */

else if(ch=='d') {

  length.byte[1] = getch();

  length.byte[0]= getch();

  flags.eeprom = 0;

  if (getch() == 'E') flags.eeprom = 1;

  // putch(length);  

  // putch(length>>8);

  for (w=0;w     buff[w] = getch();                         // Store data in buffer, can't keep up with serial data stream whilst programming pages

  }

  if (getch() ==0x20) 

  {

//   putch('W');

#ifdef EERPOM

if (flags.eeprom) {                 //Write to EEPROM one byte at a time

for(w=0;w eeprom_wb(address.word,buff[w]);

address.word++;

}

// putch('E');

} else

#else

if (flags.eeprom==0)

#endif 

{ //Write to FLASH one page at a time

//if (address.byte[1]>127) address_high = 0x01; //Only possible with m128, m256 will need 3rd address byte. FIXME

//else address_high = 0x00;

//address = address << 1;         //address * 2 -> byte location

//if ((length.byte[0] & 0x01)) length++; //Even up an odd number of bytes

// putch('F');

#if 1

cli(); //Disable interrupts, just to be sure

// sbi(PORTD,3);

//sbi(LED_PORT,LED);

while(bit_is_set(EECR,EEWE)); //Wait for previous EEPROM writes to complete

// sbi(PORTD,3);

//cbi(LED_PORT,LED);

asm volatile(

"clr r17 nt" //page_word_count

"lds r30,address nt" //Address of FLASH location (in words)

"lds r31,address+1 nt"

"lsl   r30 nt"  //address * 2 -> byte location

"rol   r31 nt" 

"ldi r28,lo8(buff) nt" //Start of buffer array in RAM

"ldi r29,hi8(buff) nt"

"lds r24,length nt" //Length of data to be written (in bytes)

"lds r25,length+1 nt"

"sbrs r24,0 nt"  //Even up an odd number of bytes

"rjmp length_loop nt"

"adiw r24,1 nt"

"length_loop: nt" //Main loop, repeat for number of words in block  

"cpi r17,0x00 nt" //If page_word_count=0 then erase page