AVR单片机BootLoader功能应用源码与详细介绍 -

#include "bootloader.h"
//串口初始化
void ComInit(void)
{
UBRR0H = BAUDREG/256;
UBRR0L = BAUDREG%256;
UCSR0A = 0;
UCSR0B = (1 << RXEN0)|(1 << TXEN0);
UCSR0C = (1 << UCSZ00)|(1 << UCSZ01);
}
//使用定时器1：产生以毫秒为单位的时间
void TimerInit()
{
OCR1A = (unsigned int)(timeclk * (F_CPU / (1024 * 1000.0f)));
TCCR1A = 0;
TCCR1B = (1 << WGM12)|(1 << CS12)|(1 << CS10);
}
//更新一个Flash页
void write_one_page(unsigned char *buf)
{
boot_page_erase(FlashAddr);
boot_spm_busy_wait();
for(pagptr = 0; pagptr < SPM_PAGESIZE; pagptr += 2)
{
boot_page_fill(pagptr, buf[pagptr] + (buf[pagptr + 1] << 8));
}
boot_page_write(FlashAddr);
boot_spm_busy_wait();
}
//跳转到用户程序
void quit()
{
boot_rww_enable();
(*((void(*)(void))PROG_START))();
}
//写入数据到串口
void WriteCom(unsigned char dat)
{
#if RS485
RS485Enable();
#endif
UDR0 = dat;
while(!(UCSR0A & (1<<TXC0)));
UCSR0A |= (1<<TXC0);
#if RS485
RS485Disable();
#endif
}
//等待串口数据
unsigned char WaitCom()
{
while(!(UCSR0A & (1<<RXC0)));
return UDR0;
}
//向串口输出字符串
void putstr(const char *str)
{
while(*str)
WriteCom(*str++);
WriteCom(0x0D);
WriteCom(0x0A);
}
//CRC校验
void crc16(unsigned char *buf, unsigned char n)
{
unsigned char j;
unsigned char i;
unsigned int crc, t;
crc = 0;
for(j = n; j > 0; j--)
{
crc = (crc ^ (((unsigned int) *buf) << 8));
for(i = 8; i > 0; i--)
{
t = crc << 1;
if(crc & 0x8000)
t = t ^ 0x1021;
crc = t;
}
buf++;
}
ch = crc / 256;
cl = crc % 256;
}
int main(void)
{
unsigned char cnt;
unsigned char packNO;
unsigned char crch, crcl;
unsigned char li;
asm volatile("cli": : );
wdt_enable(WDTO_1S);
TimerInit();
#if RS485
DDRREG(RS485PORT) |= (1 << RS485TXEn);
RS485Disable();
#endif
ComInit();
putstr(msg1);
cnt = TimeOutCnt;
cl = 0;
while(1)
{
if(TIFR1 & (1<<OCF1A))
{
TIFR1 |= (1 << OCF1A);
if(cl == CONNECTCNT)
break;
wdt_reset();
cnt--;
if(cnt == 0)
{
putstr(msg2);
quit();
}
}
if(DataInCom())
{
if(ReadCom() == KEY[cl])
cl++;
else
cl = 0;
}
}
putstr(msg3);
cnt = TimeOutCntC;
while(1)
{
if(TIFR1 & (1<<OCF1A))
{
TIFR1 |= (1 << OCF1A);
WriteCom(XMODEM_RWC) ;
wdt_reset();
cnt--;
if(cnt == 0)
{
putstr(msg2);
quit();
}
}
if(DataInCom())
{
if(ReadCom() == XMODEM_SOH)
break;
}
}
TCCR1B = 0;
packNO = 0;
bufptr = 0;
cnt = 0;
FlashAddr = 0;
do
{
packNO++;
ch = WaitCom();
cl = ~WaitCom();
if ((packNO == ch) && (packNO == cl))
{
for(li = 0; li < BUFFERSIZE; li++)
{
buf[bufptr++] = WaitCom();
}
crch = WaitCom();
crcl = WaitCom();
crc16(&buf[bufptr - BUFFERSIZE], BUFFERSIZE);
if((crch == ch) && (crcl == cl))
{
if(FlashAddr < BootStart)
{
while(bufptr > 0)
{
write_one_page(&buf[BUFSIZE - bufptr]);
FlashAddr += SPM_PAGESIZE;
bufptr -= SPM_PAGESIZE;
}
}
else
{
bufptr = 0;
}
WriteCom(XMODEM_ACK);
cnt = 0;
wdt_reset();
}
else
{
WriteCom(XMODEM_NAK);
cnt++;
}
}
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