Arduino解析

　　Arduino是一个基于开源代码的快速电子原型开发平台，其由各种型号的Arduino开发板及Arduino IDE组成（官网，中文社区）。目前的Arduino开发板是基于AVR单片机系统开发，并在其基础上作了较完善的软硬件封装，目的是尽量屏蔽底层硬件的影响便于快速开发。
　
1. Arduino开发板硬件解析，基于Arduino UNO R3.
　　原理图下载：点我
　　实物图如下：
　　

　　
　　开发板硬件主要由 USB 控制器，AVR单片机 Atmega 328P 系统，电源系统及相应的一些外围电路组成。
　　1. 电源系统，开发板可采用“DC-5”或“USB接口”供电。
　　2. USB控制器，从原理图可以看出其与Atmega 328P的USART串口相连，用于传输数据；端口PD7用于控制Atmega 328P的复位，已便在Arduino IDE下载程序时，使单片机复位进入Bootloader程序。
　　通常的AVR单片机开发采用ISP接口下载程序，需要专门的ISP下载器。Arduino为了简化外围设备，采用USB串口下载程序。其原理是将AVR单片机系统程序分为“Bootloader”和“APP”两部分，“Bootloader”负责将USB串口接收的程序通过自编程（IAP）烧写至Flash，并在一定条件下控制程序跳转至“APP”区执行；“APP”是真正用户编写的程序。（PS: 有些单片机厂商在出厂前已将“Bootloader”固化到单片机，如 STM32 系列单片机，其可通过串口，I2C 等接口程接收用户程序，用户通过控制 BOOT 相关引脚的电平，控制程序跳转。）
　　3. AVR 单片机 Atmega 328P 系统，含时钟电路、复位电路、I/O端口。
　　
　　待续。。。
　　
2. Arduino Bootloader源码分析
　　在Ardunino IDE的安装目录下，个人目录：“E:\Arduino\hardware\arduino\avr\bootloaders\atmega”。
　　Bootloader主要实现功能：1. 接收外部发送来的程序；2. 将程序烧写到Flash；3. 控制程序跳转。
　　
　　待续。。。
　

/**********************************************************//* Serial Bootloader for Atmel megaAVR Controllers        *//*                                                        *//* tested with ATmegarduino8, ATmega128 and ATmega168  *//* should work with other mega's, see code for details    *//*                                                        *//* ATmegaBOOT.c                                           *//*                                                        *//*                                                        *//* 20090308: integrated Mega changes into main bootloader *//*           source by D. Mellis                          *//* 20080930: hacked for Arduino Mega (with the 1280       *//*           processor, backwards compatible)             *//*           by D. Cuartielles                            *//* 20070626: hacked for Arduino Diecimila (which auto-    *//*           resets when a USB connection is made to it)  *//*           by D. Mellis                                 *//* 20060802: hacked for Arduino by D. Cuartielles         *//*           based on a previous hack by D. Mellis        *//*           and D. Cuartielles                           *//*                                                        *//* Monitor and debug functions were added to the original *//* code by Dr. Erik Lins, chip45.com. (See below)         *//*                                                        *//* Thanks to Karl Pitrich for fixing a bootloader pin     *//* problem and more informative LED blinking!             *//*                                                        *//* For the latest version see:                            *//* http://www.chip45.com/                                 *//*                                                        *//* ------------------------------------------------------ *//*                                                        *//* based on stk500boot.c                                  *//* Copyright (c) 2003, Jason P. Kyle                      *//* All rights reserved.                                   *//* see avr1.org for original file and information         *//*                                                        *//* This program is free software; you can redistribute it *//* and/or modify it under the terms of the GNU General    *//* Public License as published by the Free Software       *//* Foundation; either version 2 of the License, or        *//* (at your option) any later version.                    *//*                                                        *//* This program is distributed in the hope that it will   *//* be useful, but WITHOUT ANY WARRANTY; without even the  *//* implied warranty of MERCHANTABILITY or FITNESS FOR A   *//* PARTICULAR PURPOSE.  See the GNU General Public        *//* License for more details.                              *//*                                                        *//* You should have received a copy of the GNU General     *//* Public License along with this program; if not, write  *//* to the Free Software Foundation, Inc.,                 *//* 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA *//*                                                        *//* Licence can be viewed at                               *//* http://www.fsf.org/licenses/gpl.txt                    *//*                                                        *//* Target = Atmel AVR m128,m64,m32,m16,m8,m162,m163,m169, *//* m8515,m8535. ATmega161 has a very small boot block so  *//* isn't supported.                                       *//*                                                        *//* Tested with m168                                       *//**********************************************************//* some includes */#include <inttypes.h>#include <avr/io.h>#include <avr/pgmspace.h>#include <avr/interrupt.h>#include <avr/wdt.h>#include <util/delay.h>/* the current avr-libc eeprom functions do not support the ATmega168 *//* own eeprom write/read functions are used instead */#if !defined(__AVR_ATmega168__) || !defined(__AVR_ATmega328P__) || !defined(__AVR_ATmega328__)#include <avr/eeprom.h>#endif/* Use the F_CPU defined in Makefile *//* 20060803: hacked by DojoCorp *//* 20070626: hacked by David A. Mellis to decrease waiting time for auto-reset *//* set the waiting time for the bootloader *//* get this from the Makefile instead *//* #define MAX_TIME_COUNT (F_CPU>>4) *//* 20070707: hacked by David A. Mellis - after this many errors give up and launch application */#define MAX_ERROR_COUNT 5/* set the UART baud rate *//* 20060803: hacked by DojoCorp *///#define BAUD_RATE   115200#ifndef BAUD_RATE#define BAUD_RATE   19200#endif/* SW_MAJOR and MINOR needs to be updated from time to time to avoid warning message from AVR Studio *//* never allow AVR Studio to do an update !!!! */#define HW_VER   0x02#define SW_MAJOR 0x01#define SW_MINOR 0x10/* Adjust to suit whatever pin your hardware uses to enter the bootloader *//* ATmega128 has two UARTS so two pins are used to enter bootloader and select UART *//* ATmega1280 has four UARTS, but for Arduino Mega, we will only use RXD0 to get code *//* BL0... means UART0, BL1... means UART1 */#ifdef __AVR_ATmega128__#define BL_DDR  DDRF#define BL_PORT PORTF#define BL_PIN  PINF#define BL0     PINF7#define BL1     PINF6#elif defined __AVR_ATmega1280__ /* we just don't do anything for the MEGA and enter bootloader on reset anyway*/#else/* other ATmegas have only one UART, so only one pin is defined to enter bootloader */#define BL_DDR  DDRD#define BL_PORT PORTD#define BL_PIN  PIND#define BL      PIND6#endif/* onboard LED is used to indicate, that the bootloader was entered (3x flashing) *//* if monitor functions are included, LED goes on after monitor was entered */#if defined __AVR_ATmega128__ || defined __AVR_ATmega1280__/* Onboard LED is connected to pin PB7 (e.g. Crumb128, PROBOmega128, Savvy128, Arduino Mega) */#define LED_DDR  DDRB#define LED_PORT PORTB#define LED_PIN  PINB#define LED      PINB7#else/* Onboard LED is connected to pin PB5 in Arduino NG, Diecimila, and Duomilanuove */ /* other boards like e.g. Crumb8, Crumb168 are using PB2 */#define LED_DDR  DDRB#define LED_PORT PORTB#define LED_PIN  PINB#define LED      PINB5#endif/* monitor functions will only be compiled when using ATmega128, due to bootblock size constraints */#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)#define MONITOR 1#endif/* define various device id's *//* manufacturer byte is always the same */#define SIG1    0x1E    // Yep, Atmel is the only manufacturer of AVR micros.  Single source :(#if defined __AVR_ATmega1280__#define SIG2    0x97#define SIG3    0x03#define PAGE_SIZE   0x80U   //128 words#elif defined __AVR_ATmega1281__#define SIG2    0x97#define SIG3    0x04#define PAGE_SIZE   0x80U   //128 words#elif defined __AVR_ATmega128__#define SIG2    0x97#define SIG3    0x02#define PAGE_SIZE   0x80U   //128 words#elif defined __AVR_ATmega64__#define SIG2    0x96#define SIG3    0x02#define PAGE_SIZE   0x80U   //128 words#elif defined __AVR_ATmega32__#define SIG2    0x95#define SIG3    0x02#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega16__#define SIG2    0x94#define SIG3    0x03#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega8__#define SIG2    0x93#define SIG3    0x07#define PAGE_SIZE   0x20U   //32 words#elif defined __AVR_ATmega88__#define SIG2    0x93#define SIG3    0x0a#define PAGE_SIZE   0x20U   //32 words#elif defined __AVR_ATmega168__#define SIG2    0x94#define SIG3    0x06#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega328P__#define SIG2    0x95#define SIG3    0x0F#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega328__#define SIG2    0x95#define SIG3    0x14#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega162__#define SIG2    0x94#define SIG3    0x04#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega163__#define SIG2    0x94#define SIG3    0x02#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega169__#define SIG2    0x94#define SIG3    0x05#define PAGE_SIZE   0x40U   //64 words#elif defined __AVR_ATmega8515__#define SIG2    0x93#define SIG3    0x06#define PAGE_SIZE   0x20U   //32 words#elif defined __AVR_ATmega8535__#define SIG2    0x93#define SIG3    0x08#define PAGE_SIZE   0x20U   //32 words#endif/* function prototypes */void putch(char);char getch(void);void getNch(uint8_t);void byte_response(uint8_t);void nothing_response(void);char gethex(void);void puthex(char);void flash_led(uint8_t);/* some variables */union address_union {    uint16_t word;    uint8_t  byte[2];} address;union length_union {    uint16_t word;    uint8_t  byte[2];} length;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 bootuart = 0;uint8_t error_count = 0;void (*app_start)(void) = 0x0000;/* main program starts here */int main(void){    uint8_t ch,ch2;    uint16_t w;#ifdef WATCHDOG_MODS    ch = MCUSR;    MCUSR = 0;    WDTCSR |= _BV(WDCE) | _BV(WDE);    WDTCSR = 0;    // Check if the WDT was used to reset, in which case we dont bootload and skip straight to the code. woot.    if (! (ch &  _BV(EXTRF))) // if its a not an external reset...        app_start();  // skip bootloader#else    asm volatile("nop\n\t");#endif    /* set pin direction for bootloader pin and enable pullup */    /* for ATmega128, two pins need to be initialized */#ifdef __AVR_ATmega128__    BL_DDR &= ~_BV(BL0);    BL_DDR &= ~_BV(BL1);    BL_PORT |= _BV(BL0);    BL_PORT |= _BV(BL1);#else    /* We run the bootloader regardless of the state of this pin.  Thus, don't    put it in a different state than the other pins.  --DAM, 070709    This also applies to Arduino Mega -- DC, 080930    BL_DDR &= ~_BV(BL);    BL_PORT |= _BV(BL);    */#endif#ifdef __AVR_ATmega128__    /* check which UART should be used for booting */    if(bit_is_clear(BL_PIN, BL0)) {        bootuart = 1;    }    else if(bit_is_clear(BL_PIN, BL1)) {        bootuart = 2;    }#endif#if defined __AVR_ATmega1280__    /* the mega1280 chip has four serial ports ... we could eventually use any of them, or not? */    /* however, we don't wanna confuse people, to avoid making a mess, we will stick to RXD0, TXD0 */    bootuart = 1;#endif    /* check if flash is programmed already, if not start bootloader anyway */    if(pgm_read_byte_near(0x0000) != 0xFF) {#ifdef __AVR_ATmega128__    /* no UART was selected, start application */    if(!bootuart) {        app_start();    }#else    /* check if bootloader pin is set low */    /* we don't start this part neither for the m8, nor m168 */    //if(bit_is_set(BL_PIN, BL)) {    //      app_start();    //    }#endif    }#ifdef __AVR_ATmega128__        /* no bootuart was selected, default to uart 0 */    if(!bootuart) {        bootuart = 1;    }#endif    /* initialize UART(s) depending on CPU defined */#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)    if(bootuart == 1) {        UBRR0L = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);        UBRR0H = (F_CPU/(BAUD_RATE*16L)-1) >> 8;        UCSR0A = 0x00;        UCSR0C = 0x06;        UCSR0B = _BV(TXEN0)|_BV(RXEN0);    }    if(bootuart == 2) {        UBRR1L = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);        UBRR1H = (F_CPU/(BAUD_RATE*16L)-1) >> 8;        UCSR1A = 0x00;        UCSR1C = 0x06;        UCSR1B = _BV(TXEN1)|_BV(RXEN1);    }#elif defined __AVR_ATmega163__    UBRR = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);    UBRRHI = (F_CPU/(BAUD_RATE*16L)-1) >> 8;    UCSRA = 0x00;    UCSRB = _BV(TXEN)|_BV(RXEN);    #elif defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__) || defined (__AVR_ATmega328__)#ifdef DOUBLE_SPEED    UCSR0A = (1<<U2X0); //Double speed mode USART0    UBRR0L = (uint8_t)(F_CPU/(BAUD_RATE*8L)-1);    UBRR0H = (F_CPU/(BAUD_RATE*8L)-1) >> 8;#else    UBRR0L = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);    UBRR0H = (F_CPU/(BAUD_RATE*16L)-1) >> 8;#endif    UCSR0B = (1<<RXEN0) | (1<<TXEN0);    UCSR0C = (1<<UCSZ00) | (1<<UCSZ01);    /* Enable internal pull-up resistor on pin D0 (RX), in order    to supress line noise that prevents the bootloader from    timing out (DAM: 20070509) */    DDRD &= ~_BV(PIND0);    PORTD |= _BV(PIND0);#elif defined __AVR_ATmega8__    /* m8 */    UBRRH = (((F_CPU/BAUD_RATE)/16)-1)>>8;  // set baud rate    UBRRL = (((F_CPU/BAUD_RATE)/16)-1);    UCSRB = (1<<RXEN)|(1<<TXEN);  // enable Rx & Tx    UCSRC = (1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0);  // config USART; 8N1#else    /* m16,m32,m169,m8515,m8535 */    UBRRL = (uint8_t)(F_CPU/(BAUD_RATE*16L)-1);    UBRRH = (F_CPU/(BAUD_RATE*16L)-1) >> 8;    UCSRA = 0x00;    UCSRC = 0x06;    UCSRB = _BV(TXEN)|_BV(RXEN);#endif#if defined __AVR_ATmega1280__    /* Enable internal pull-up resistor on pin D0 (RX), in order    to supress line noise that prevents the bootloader from    timing out (DAM: 20070509) */    /* feature added to the Arduino Mega --DC: 080930 */    DDRE &= ~_BV(PINE0);    PORTE |= _BV(PINE0);#endif    /* set LED pin as output */    LED_DDR |= _BV(LED);    /* flash onboard LED to signal entering of bootloader */#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)    // 4x for UART0, 5x for UART1    flash_led(NUM_LED_FLASHES + bootuart);#else    flash_led(NUM_LED_FLASHES);#endif    /* 20050803: by DojoCorp, this is one of the parts provoking the         system to stop listening, cancelled from the original */    //putch('\0');    /* forever loop */    for (;;) {    /* get character from UART */    ch = getch();    /* A bunch of if...else if... gives smaller code than switch...case ! */    /* Hello is anyone home ? */     if(ch=='0') {        nothing_response();    }    /* 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);        } else {            if (++error_count == MAX_ERROR_COUNT)                app_start();        }    }    /* 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();    }    /* P: Enter programming mode  */    /* R: Erase device, don't care as we will erase one page at a time anyway.  */    else if(ch=='P' || ch=='R') {        nothing_response();    }    /* Leave programming mode  */    else if(ch=='Q') {        nothing_response();#ifdef WATCHDOG_MODS        // autoreset via watchdog (sneaky!)        WDTCSR = _BV(WDE);        while (1); // 16 ms#endif    }    /* Set address, little endian. EEPROM in bytes, FLASH in words  */    /* Perhaps extra address bytes may be added in future to support > 128kB FLASH.  */    /* This might explain why little endian was used here, big endian used everywhere else.  */    else if(ch=='U') {        address.byte[0] = getch();        address.byte[1] = getch();        nothing_response();    }    /* Universal SPI programming command, disabled.  Would be used for fuses and lock bits.  */    else if(ch=='V') {        if (getch() == 0x30) {            getch();            ch = getch();            getch();            if (ch == 0) {                byte_response(SIG1);            } else if (ch == 1) {                byte_response(SIG2);             } else {                byte_response(SIG3);            }         } else {            getNch(3);            byte_response(0x00);        }    }    /* 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;        for (w=0;w<length.word;w++) {            buff[w] = getch();                          // Store data in buffer, can't keep up with serial data stream whilst programming pages        }        if (getch() == ' ') {            if (flags.eeprom) {                     //Write to EEPROM one byte at a time                address.word <<= 1;                for(w=0;w<length.word;w++) {#if defined(__AVR_ATmega168__)  || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)                    while(EECR & (1<<EEPE));                    EEAR = (uint16_t)(void *)address.word;                    EEDR = buff[w];                    EECR |= (1<<EEMPE);                    EECR |= (1<<EEPE);#else                    eeprom_write_byte((void *)address.word,buff[w]);#endif                    address.word++;                }                       }            else {                          //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;#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega1281__)                RAMPZ = address_high;#endif                address.word = address.word << 1;           //address * 2 -> byte location                /* if ((length.byte[0] & 0x01) == 0x01) length.word++;  //Even up an odd number of bytes */                if ((length.byte[0] & 0x01)) length.word++; //Even up an odd number of bytes                cli();                  //Disable interrupts, just to be sure#if defined(EEPE)                while(bit_is_set(EECR,EEPE));           //Wait for previous EEPROM writes to complete#else                while(bit_is_set(EECR,EEWE));           //Wait for previous EEPROM writes to complete#endif                asm volatile(                     "clr   r17     \n\t"   //page_word_count                     "lds   r30,address \n\t"   //Address of FLASH location (in bytes)                     "lds   r31,address+1   \n\t"                     "ldi   r28,lo8(buff)   \n\t"   //Start of buffer array in RAM                     "ldi   r29,hi8(buff)   \n\t"                     "lds   r24,length  \n\t"   //Length of data to be written (in bytes)                     "lds   r25,length+1    \n\t"                     "length_loop:      \n\t"   //Main loop, repeat for number of words in block                                                                              "cpi   r17,0x00    \n\t"   //If page_word_count=0 then erase page                     "brne  no_page_erase   \n\t"                                             "wait_spm1:        \n\t"                     "lds   r16,%0      \n\t"   //Wait for previous spm to complete                     "andi  r16,1           \n\t"                     "cpi   r16,1           \n\t"                     "breq  wait_spm1       \n\t"                     "ldi   r16,0x03    \n\t"   //Erase page pointed to by Z                     "sts   %0,r16      \n\t"                     "spm           \n\t"                            #ifdef __AVR_ATmega163__                     ".word 0xFFFF      \n\t"                     "nop           \n\t"#endif                     "wait_spm2:        \n\t"                     "lds   r16,%0      \n\t"   //Wait for previous spm to complete                     "andi  r16,1           \n\t"                     "cpi   r16,1           \n\t"                     "breq  wait_spm2       \n\t"                                                         "ldi   r16,0x11    \n\t"   //Re-enable RWW section                     "sts   %0,r16      \n\t"                                                         "spm           \n\t"#ifdef __AVR_ATmega163__                     ".word 0xFFFF      \n\t"                     "nop           \n\t"#endif                     "no_page_erase:        \n\t"                                                 "ld    r0,Y+       \n\t"   //Write 2 bytes into page buffer                     "ld    r1,Y+       \n\t"                                                 "wait_spm3:        \n\t"                     "lds   r16,%0      \n\t"   //Wait for previous spm to complete                     "andi  r16,1           \n\t"                     "cpi   r16,1           \n\t"                     "breq  wait_spm3       \n\t"                     "ldi   r16,0x01    \n\t"   //Load r0,r1 into FLASH page buffer                     "sts   %0,r16      \n\t"                     "spm           \n\t"                     "inc   r17     \n\t"   //page_word_count++                     "cpi r17,%1            \n\t"                     "brlo  same_page   \n\t"   //Still same page in FLASH                     "write_page:       \n\t"                     "clr   r17     \n\t"   //New page, write current one first                     "wait_spm4:        \n\t"                     "lds   r16,%0      \n\t"   //Wait for previous spm to complete                     "andi  r16,1           \n\t"                     "cpi   r16,1           \n\t"                     "breq  wait_spm4       \n\t"#ifdef __AVR_ATmega163__                     "andi  r30,0x80    \n\t"   // m163 requires Z6:Z1 to be zero during page write#endif                                                                            "ldi   r16,0x05    \n\t"   //Write page pointed to by Z                     "sts   %0,r16      \n\t"                     "spm           \n\t"#ifdef __AVR_ATmega163__                     ".word 0xFFFF      \n\t"                     "nop           \n\t"                     "ori   r30,0x7E    \n\t"   // recover Z6:Z1 state after page write (had to be zero during write)#endif                     "wait_spm5:        \n\t"                     "lds   r16,%0      \n\t"   //Wait for previous spm to complete                     "andi  r16,1           \n\t"                     "cpi   r16,1           \n\t"                     "breq  wait_spm5       \n\t"                                                         "ldi   r16,0x11    \n\t"   //Re-enable RWW section                     "sts   %0,r16      \n\t"                                                         "spm           \n\t"                            #ifdef __AVR_ATmega163__                     ".word 0xFFFF      \n\t"                     "nop           \n\t"#endif                     "same_page:        \n\t"                                                 "adiw  r30,2       \n\t"   //Next word in FLASH                     "sbiw  r24,2       \n\t"   //length-2                     "breq  final_write \n\t"   //Finished                     "rjmp  length_loop \n\t"                     "final_write:      \n\t"                     "cpi   r17,0       \n\t"                     "breq  block_done  \n\t"                     "adiw  r24,2       \n\t"   //length+2, fool above check on length after short page write                     "rjmp  write_page  \n\t"                     "block_done:       \n\t"                     "clr   __zero_reg__    \n\t"   //restore zero register#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__) || defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega1281__)                     : "=m" (SPMCSR) : "M" (PAGE_SIZE) : "r0","r16","r17","r24","r25","r28","r29","r30","r31"#else                     : "=m" (SPMCR) : "M" (PAGE_SIZE) : "r0","r16","r17","r24","r25","r28","r29","r30","r31"#endif                     );                /* Should really add a wait for RWW section to be enabled, don't actually need it since we never */                /* exit the bootloader without a power cycle anyhow */            }            putch(0x14);            putch(0x10);        } else {            if (++error_count == MAX_ERROR_COUNT)                app_start();        }           }    /* Read memory block mode, length is big endian.  */    else if(ch=='t') {        length.byte[1] = getch();        length.byte[0] = getch();#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)        if (address.word>0x7FFF) flags.rampz = 1;       // No go with m256, FIXME        else flags.rampz = 0;#endif        address.word = address.word << 1;           // address * 2 -> byte location        if (getch() == 'E') flags.eeprom = 1;        else flags.eeprom = 0;        if (getch() == ' ') {                       // Command terminator            putch(0x14);            for (w=0;w < length.word;w++) {             // Can handle odd and even lengths okay                if (flags.eeprom) {                         // Byte access EEPROM read#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)                    while(EECR & (1<<EEPE));                    EEAR = (uint16_t)(void *)address.word;                    EECR |= (1<<EERE);                    putch(EEDR);#else                    putch(eeprom_read_byte((void *)address.word));#endif                    address.word++;                }                else {                    if (!flags.rampz) putch(pgm_read_byte_near(address.word));#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)                    else putch(pgm_read_byte_far(address.word + 0x10000));                    // Hmmmm, yuck  FIXME when m256 arrvies#endif                    address.word++;                }            }            putch(0x10);        }    }    /* Get device signature bytes  */    else if(ch=='u') {        if (getch() == ' ') {            putch(0x14);            putch(SIG1);            putch(SIG2);            putch(SIG3);            putch(0x10);        } else {            if (++error_count == MAX_ERROR_COUNT)                app_start();        }    }    /* Read oscillator calibration byte */    else if(ch=='v') {        byte_response(0x00);    }#if defined MONITOR     /* here come the extended monitor commands by Erik Lins */    /* check for three times exclamation mark pressed */    else if(ch=='!') {        ch = getch();        if(ch=='!') {        ch = getch();        if(ch=='!') {            PGM_P welcome = "";#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)            uint16_t extaddr;#endif            uint8_t addrl, addrh;#ifdef CRUMB128            welcome = "ATmegaBOOT / Crumb128 - (C) J.P.Kyle, E.Lins - 050815\n\r";#elif defined PROBOMEGA128            welcome = "ATmegaBOOT / PROBOmega128 - (C) J.P.Kyle, E.Lins - 050815\n\r";#elif defined SAVVY128            welcome = "ATmegaBOOT / Savvy128 - (C) J.P.Kyle, E.Lins - 050815\n\r";#elif defined __AVR_ATmega1280__             welcome = "ATmegaBOOT / Arduino Mega - (C) Arduino LLC - 090930\n\r";#endif            /* turn on LED */            LED_DDR |= _BV(LED);            LED_PORT &= ~_BV(LED);            /* print a welcome message and command overview */            for(i=0; welcome[i] != '\0'; ++i) {                putch(welcome[i]);            }            /* test for valid commands */            for(;;) {                putch('\n');                putch('\r');                putch(':');                putch(' ');                ch = getch();                putch(ch);                /* toggle LED */                if(ch == 't') {                    if(bit_is_set(LED_PIN,LED)) {                        LED_PORT &= ~_BV(LED);                        putch('1');                    } else {                        LED_PORT |= _BV(LED);                        putch('0');                    }                }                 /* read byte from address */                else if(ch == 'r') {                    ch = getch(); putch(ch);                    addrh = gethex();                    addrl = gethex();                    putch('=');                    ch = *(uint8_t *)((addrh << 8) + addrl);                    puthex(ch);                }                /* write a byte to address  */                else if(ch == 'w') {                    ch = getch(); putch(ch);                    addrh = gethex();                    addrl = gethex();                    ch = getch(); putch(ch);                    ch = gethex();                    *(uint8_t *)((addrh << 8) + addrl) = ch;                }                /* read from uart and echo back */                else if(ch == 'u') {                    for(;;) {                        putch(getch());                    }                }#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)                /* external bus loop  */                else if(ch == 'b') {                    putch('b');                    putch('u');                    putch('s');                    MCUCR = 0x80;                    XMCRA = 0;                    XMCRB = 0;                    extaddr = 0x1100;                    for(;;) {                        ch = *(volatile uint8_t *)extaddr;                        if(++extaddr == 0) {                            extaddr = 0x1100;                        }                    }                }#endif                else if(ch == 'j') {                    app_start();                }            } /* end of monitor functions */        }        }    }    /* end of monitor */#endif    else if (++error_count == MAX_ERROR_COUNT) {        app_start();    }    } /* end of forever loop */}char gethexnib(void) {    char a;    a = getch(); putch(a);    if(a >= 'a') {        return (a - 'a' + 0x0a);    } else if(a >= '0') {        return(a - '0');    }    return a;}char gethex(void) {    return (gethexnib() << 4) + gethexnib();}void puthex(char ch) {    char ah;    ah = ch >> 4;    if(ah >= 0x0a) {        ah = ah - 0x0a + 'a';    } else {        ah += '0';    }    ch &= 0x0f;    if(ch >= 0x0a) {        ch = ch - 0x0a + 'a';    } else {        ch += '0';    }    putch(ah);    putch(ch);}void putch(char ch){#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)    if(bootuart == 1) {        while (!(UCSR0A & _BV(UDRE0)));        UDR0 = ch;    }    else if (bootuart == 2) {        while (!(UCSR1A & _BV(UDRE1)));        UDR1 = ch;    }#elif defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__) || defined (__AVR_ATmega328__)    while (!(UCSR0A & _BV(UDRE0)));    UDR0 = ch;#else    /* m8,16,32,169,8515,8535,163 */    while (!(UCSRA & _BV(UDRE)));    UDR = ch;#endif}char getch(void){#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)    uint32_t count = 0;    if(bootuart == 1) {        while(!(UCSR0A & _BV(RXC0))) {            /* 20060803 DojoCorp:: Addon coming from the previous Bootloader*/                           /* HACKME:: here is a good place to count times*/            count++;            if (count > MAX_TIME_COUNT)                app_start();        }        return UDR0;    }    else if(bootuart == 2) {        while(!(UCSR1A & _BV(RXC1))) {            /* 20060803 DojoCorp:: Addon coming from the previous Bootloader*/                           /* HACKME:: here is a good place to count times*/            count++;            if (count > MAX_TIME_COUNT)                app_start();        }        return UDR1;    }    return 0;#elif defined(__AVR_ATmega168__)  || defined(__AVR_ATmega328P__) || defined (__AVR_ATmega328__)    uint32_t count = 0;    while(!(UCSR0A & _BV(RXC0))){        /* 20060803 DojoCorp:: Addon coming from the previous Bootloader*/                       /* HACKME:: here is a good place to count times*/        count++;        if (count > MAX_TIME_COUNT)            app_start();    }    return UDR0;#else    /* m8,16,32,169,8515,8535,163 */    uint32_t count = 0;    while(!(UCSRA & _BV(RXC))){        /* 20060803 DojoCorp:: Addon coming from the previous Bootloader*/                       /* HACKME:: here is a good place to count times*/        count++;        if (count > MAX_TIME_COUNT)            app_start();    }    return UDR;#endif}void getNch(uint8_t count){    while(count--) {#if defined(__AVR_ATmega128__) || defined(__AVR_ATmega1280__)        if(bootuart == 1) {            while(!(UCSR0A & _BV(RXC0)));            UDR0;        }         else if(bootuart == 2) {            while(!(UCSR1A & _BV(RXC1)));            UDR1;        }#elif defined(__AVR_ATmega168__)  || defined(__AVR_ATmega328P__) || defined (__AVR_ATmega328__)        getch();#else        /* m8,16,32,169,8515,8535,163 */        /* 20060803 DojoCorp:: Addon coming from the previous Bootloader*/                       //while(!(UCSRA & _BV(RXC)));        //UDR;        getch(); // need to handle time out#endif          }}void byte_response(uint8_t val){    if (getch() == ' ') {        putch(0x14);        putch(val);        putch(0x10);    } else {        if (++error_count == MAX_ERROR_COUNT)            app_start();    }}void nothing_response(void){    if (getch() == ' ') {        putch(0x14);        putch(0x10);    } else {        if (++error_count == MAX_ERROR_COUNT)            app_start();    }}void flash_led(uint8_t count){    while (count--) {        LED_PORT |= _BV(LED);        _delay_ms(100);        LED_PORT &= ~_BV(LED);        _delay_ms(100);    }}/* end of file ATmegaBOOT.c */