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发表于 2006-5-4 20:02:08
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根据马老师的程序，改写成了mega8的bootloader，未经马老师同意贴在这里，还请见谅。你的学生。
//meg8 bootloader
//BOOTSZ1 BOOTSZ0=00
//meg8 bootloader
//BOOTSZ1 BOOTSZ0=00
#include <iom8v.h>
#define SPM_PAGESIZE 64 //M8的一个Flash页为64字节(32字)
#define BAUD 38400 //波特率采用38400bps
#define CRYSTAL 8000000 //系统时钟8MHz
//计算和定义M128的波特率设置参数
#define BAUD_SETTING (unsigned char)((unsigned long)CRYSTAL/(16*(unsigned long)BAUD)-1)
#define BAUD_H (unsigned char)(BAUD_SETTING>>8)
#define BAUD_L (unsigned char)BAUD_SETTING
#define DATA_BUFFER_SIZE 128 //定义接收缓冲区长度
//定义Xmoden控制字符
#define XMODEM_NUL 0x00
#define XMODEM_SOH 0x01
#define XMODEM_STX 0x02
#define XMODEM_EOT 0x04
#define XMODEM_ACK 0x06
#define XMODEM_NAK 0x15
#define XMODEM_CAN 0x18
#define XMODEM_EOF 0x1A
#define XMODEM_RECIEVING_WAIT_CHAR 'C'
//定义全局变量
const char startupString[]="Type 'd' download, Others run app.
\r\0";
const char loadString[]="download over
\r\0";
char data[DATA_BUFFER_SIZE];
unsigned int address = 0;
//擦除(code=0x03)和写入(code=0x05)一个Flash页
void boot_page_ew(unsigned int p_address,char code)
{
asm("mov r30,r16
"
"mov r31,r17
"
// "out 0x3b,r18
");
); //将页地址放入Z寄存器和RAMPZ的Bit0中
SPMCR = code; //寄存器SPMCSR中为操作码
asm("spm
"); //对指定Flash页进行操作
}
//填充Flash缓冲页中的一个字
void boot_page_fill(unsigned int address,int data)
{
asm("mov r30,r16
"
"mov r31,r17
" //Z寄存器中为填冲页内地址
"mov r0,r18
"
"mov r1,r19
"); //R0R1中为一个指令字
SPMCR = 0x01;
asm("spm
");
}
//等待一个Flash页的写完成
void wait_page_rw_ok(void)
{
while(SPMCR & 0x40)
{
while(SPMCR & 0x01);
SPMCR = 0x11;
asm("spm
");
}
}
//更新一个Flash页的完整处理
void write_two_page(void)
{
//128字节分两页
int i;
boot_page_ew(address,0x03); //擦除一个Flash页
wait_page_rw_ok(); //等待擦除完成
for(i=0;i<SPM_PAGESIZE;i+=2) //将数据填入Flash缓冲页中
{
boot_page_fill(i, data+(data[i+1]<<8));
}
boot_page_ew(address,0x05); //将缓冲页数据写入一个Flash页
wait_page_rw_ok(); //等待写入完成
//写第2页
address += SPM_PAGESIZE; //Flash页加1
boot_page_ew(address,0x03); //擦除一个Flash页
wait_page_rw_ok(); //等待擦除完成
for(i=0;i<SPM_PAGESIZE;i+=2) //将数据填入Flash缓冲页中
{
boot_page_fill(i, data[SPM_PAGESIZE+i]+(data[SPM_PAGESIZE+i+1]<<8));
}
boot_page_ew(address,0x05); //将缓冲页数据写入一个Flash页
wait_page_rw_ok(); //等待写入完成
}
//从RS232发送一个字节
void uart_putchar(char c)
{
while(!(UCSRA & 0x20));
UDR = c;
}
//从RS232接收一个字节
int uart_getchar(void)
{
unsigned char status,res;
if(!(UCSRA & 0x80)) return -1; //no data to be received
status = UCSRA;
res = UDR;
if (status & 0x1c) return -1; // If error, return -1
return res;
}
//等待从RS232接收一个有效的字节
char uart_waitchar(void)
{
int c;
while((c=uart_getchar())==-1);
return (char)c;
}
//计算CRC
int calcrc(char *ptr, int count)
{
int crc = 0;
char i;
while (--count >= 0)
{
crc = crc ^ (int) *ptr++ << 8;
i = 8;
do
{
if (crc & 0x8000)
crc = crc << 1 ^ 0x1021;
else
crc = crc << 1;
} while(--i);
}
return (crc);
}
//退出Bootloader程序，从0x0000处执行应用程序
void quit(void)
{
uart_putchar('O');uart_putchar('K');
uart_putchar(0x0d);uart_putchar(0x0a);
uart_putchar(0x0d);uart_putchar(0x0a);
while(!(UCSRA & 0x20)); //等待结束提示信息回送完成
MCUCR = 0x01;
MCUCR = 0x00; //将中断向量表迁移到应用程序区头部
// RAMPZ = 0x00; //RAMPZ清零初始化
asm("jmp 0x0000
"); //跳转到Flash的0x0000处，执行用户的应用程序
}
//主程序
void main(void)
{
int i = 0;
unsigned char timercount = 0;
unsigned char packNO = 1;
int bufferPoint = 0;
unsigned int crc;
//初始化M128的USART0
UBRRH = BAUD_H;
UBRRL = BAUD_L; //Set baud rate
UCSRB = 0x18; //Enable Receiver and Transmitter
// UCSRC = 0x06; //Set frame format: 8data, 2stop bit
UCSRC=0x8e;//8位数据+2位STOP位,m8与m128的URSEL不同
//UCSRC=0x86;//8位数据+1位STOP位,m8与m128的URSEL不同
//初始化M8的T/C2，15ms自动重载
OCR2 = 0xEA;
TCCR2 = 0x0F;
//向PC机发送开始提示信息
while(startupString!='\0')
{
uart_putchar(startupString);
i++;
}
//3秒种等待PC下发“d”，否则退出Bootloader程序，从0x0000处执行应用程序
while(1)
{
if(uart_getchar()== 'd') break;
if (TIFR & 0x80) //timer2 over flow
{
if (++timercount > 200) quit(); //200*15ms = 3s
TIFR = TIFR|0x80;
}
}
//每秒向PC机发送一个控制字符“C”，等待控制字〈soh〉
while(uart_getchar()!=XMODEM_SOH) //receive the start of Xmodem
{
if(TIFR & 0x80) //timer2 over flow
{
if(++timercount > 67) //wait about 1 second
{
uart_putchar(XMODEM_RECIEVING_WAIT_CHAR); //send a "C"
timercount=0;
}
TIFR=TIFR | 0x80;
}
}
//开始接收数据块
do
{
if ((packNO == uart_waitchar()) && (packNO ==(~uart_waitchar())))
{ //核对数据块编号正确
//SPM_PAGESIZEW
for(i=0;i<128;i++) //接收128个字节数据
{
data[bufferPoint]= uart_waitchar();
bufferPoint++;
}
crc = (uart_waitchar()<<8);
crc += uart_waitchar(); //接收2个字节的CRC效验字
if(calcrc(&data[bufferPoint-128],128)==crc) //CRC校验验证
{ //正确接收128个字节数据
while(bufferPoint >= SPM_PAGESIZE)
// while(bufferPoint >= 64) //(m8每页64字节)
{ //正确接受128个字节的数据
//收到128字节写入2页Flash中
write_two_page();
address += SPM_PAGESIZE;
bufferPoint = 0;
}
uart_putchar(XMODEM_ACK); //正确收到一个数据块
packNO++; //数据块编号加1
}
else
{
uart_putchar(XMODEM_NAK); //要求重发数据块
}
}
else
{
uart_putchar(XMODEM_NAK); //要求重发数据块
}
}while(uart_waitchar()!=XMODEM_EOT); //循环接收，直到全部发完
uart_putchar(XMODEM_ACK); //通知PC机全部收到
i=0;
while(loadString!='\0')
{
uart_putchar(loadString);
i++;
}
quit(); //退出Bootloader程序，从0x0000处执行应用程序
} |
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