#include <reg52.h>
#include <string.h>
#include <intrins.h>
#include <stdio.h>
#include <absacc.h>
#include "FlashRam.h"
extern int TimeSec;

/*
Xmodem Frame form:    <SOH><blk><255-blk><--128 data bytes--><CRC hi><CRC lo>
1K-Xmodem Frame form: <SOH><blk><255-blk><--1024 data bytes--><CRC hi><CRC lo>
*/
//#define XMODEM_SOH 0x01
//#define XMODEM_STX 0x02
#define XMODEM_EOT 0x04
#define XMODEM_ACK 0x06
#define XMODEM_NAK 0x15
#define XMODEM_CAN 0x18	// Cancel


#define USE_1K_XMODEM 1  /* 1 for use 1k_xmodem, 0 for xmodem */

#if (USE_1K_XMODEM)	 //for 1K xmodem protocol
	#define XMODEM_DATA_SIZE 1024
	#define XMODEM_HEAD 0x02

#else				//for Xmodem protocol
	#define XMODEM_DATA_SIZE 128
	#define XMODEM_HEAD 0x01

#endif

unsigned char xdata frame_data[128];
unsigned char pack_counter = 0;
// Table of CRC constants - implements x^16+x^12+x^5+1
unsigned int code crc16_tab[] = {
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 
    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 
    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 
    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 
    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 
    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 
    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 
    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 
    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 
    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 
    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 
    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 
    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 
    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 
    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 
    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 
    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 
    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 
    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 
    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 
    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 
    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 
    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 
    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 
    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 
    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 
    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 
    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 
    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, 
};

/*
// 計算CRC
unsigned int crc16(unsigned char *buf, int len)
{
    int i;
    unsigned int cksum;

    cksum = 0;
    for (i = 0;  i < len;  i++) {
        cksum = crc16_tab[((cksum>>8) ^ buf[i]) & 0xFF] ^ (cksum << 8);
    }
    return cksum;
} */

// 從串口接收一字節
unsigned char serial_get_char(void)
{
	unsigned char cTm;
	while(!RI);
	cTm = SBUF;
	RI=0;
	return cTm;
}

// 向串口發送一字節
void serial_put_char(unsigned char c)
{
	while(!TI);
	TI=0;
	SBUF=c;
}

// 等串口有數據
// 返回0=無數據,1=有數據
char WaitChar(int tn)
{
	unsigned long ulTmo;
	while(tn--)
	{
		for (ulTmo=0; ulTmo<40000; ulTmo++)
		{
			if (RI)return 1;
		}
	}
	return 0;
}

// 發送數據幀
void SendRecord(unsigned char * buff)
{
	unsigned int chk;
	int i;

	serial_put_char(XMODEM_HEAD);
	serial_put_char(pack_counter);
	serial_put_char(255-pack_counter);
	chk = 0;
	for(i=0; i < XMODEM_DATA_SIZE; ++i)
	{
		chk = crc16_tab[((chk>>8) ^ buff[i]) & 0xFF] ^ (chk << 8);
		serial_put_char(buff[i]);
	}
	serial_put_char((chk >> 8));
	serial_put_char(chk);
}

// xmodem協議發送文件
// 收到請求符"C"后進入此函數
int xmodem_tx(void)
{
	char complete,retry_num;
	unsigned char ack_id;

	if (fopen()<0)
	{
		return(2);
	}

	ack_id = XMODEM_ACK;
	pack_counter = 0;
	complete = 0;

	while (complete == 0)
	{
		switch (ack_id)
		{
			case XMODEM_ACK:   // 正確應答
				retry_num = 0;
				pack_counter ++;
				memset(frame_data,0,XMODEM_DATA_SIZE);		// 緩沖區清零
				if (fread(frame_data,XMODEM_DATA_SIZE)>0)	// 從flash讀取數據到緩沖區
				{
					SendRecord(frame_data);			// 發送數據幀
					ack_id = serial_get_char();		// 等應答
					break;
				}
				else	// 數據已傳送完
				{
					ack_id = XMODEM_EOT;
                    complete = 1;
					while(ack_id != XMODEM_ACK)	 //Waiting for complete ACK
					{
						serial_put_char(XMODEM_EOT);
						ack_id = serial_get_char();
					}
					break;
				}
				break;

			case XMODEM_NAK:	// 請求重發
				if( retry_num++ > 10) //Retry too many times
				{
					complete = 1;
					serial_put_char(XMODEM_CAN);
					serial_put_char(XMODEM_CAN);
					serial_put_char(XMODEM_CAN);
					serial_put_char(XMODEM_CAN);
				}
				else
				{
					SendRecord(frame_data);	// 重發
					ack_id = serial_get_char();
				}
				break;

			default:
				complete = 1;
				serial_put_char(XMODEM_CAN);
				serial_put_char(XMODEM_CAN);
				serial_put_char(XMODEM_CAN);
				serial_put_char(XMODEM_CAN);
				break;
		}
	}
	return 0;
}

// 接收數據幀
int GetRecord(unsigned char blocknum, unsigned char *dest)
{
	unsigned char nextChar;
	int size;
	unsigned int chk;

	nextChar = serial_get_char();
	if (nextChar != (255-blocknum))
	{
		return 0;
	}
	chk = 0;
	for (size = 0; size < XMODEM_DATA_SIZE; ++size)
	{
		nextChar = serial_get_char();
		chk = crc16_tab[((chk>>8) ^ nextChar) & 0xFF] ^ (chk << 8);
		dest[size] = nextChar;
	}
	nextChar = serial_get_char();
	if (nextChar != ((chk >> 8) & 0xFF)) return 0;
	nextChar = serial_get_char();
	if (nextChar != (chk& 0xFF)) return 0;
	return 1;
}

#define INVALID_STATE 0
#define WAITING_START 1
#define WAIT_SOH 2
#define RX_PACKET 3
#define RX_EOT 4
#define SEND_NAK 5

// xmodem協議接收文件
int xmodem_rx(void)
{
	char ntry;
	char state;
	unsigned char nextChar;

	fopen();

	ntry = 0;
	pack_counter = 1;
	state = WAITING_START;

	while(1)
	{
		switch(state)
		{
			case WAITING_START:			// 請求傳送
				serial_put_char('C');	// 發送請求符
				if (WaitChar(3))
				{
					nextChar = serial_get_char();	// 接收幀頭
					if (nextChar == XMODEM_HEAD)
					{
						state = RX_PACKET;		// 收到幀頭
					}
				}
				break;

			case WAIT_SOH:	// 等幀頭
				nextChar = serial_get_char();	// 收幀頭
				if (nextChar == XMODEM_HEAD)
				{
					state = RX_PACKET;
				}

				else if (nextChar == XMODEM_EOT)	// 收到終止符
				{
					state = RX_EOT;
					serial_put_char(XMODEM_ACK);	// 回送應答符
					return (1);						// 結束
				}

				else if (nextChar == XMODEM_CAN)	// 取消
				{
					return (1);
				}
				break;

			case RX_PACKET:		// 收幀
				nextChar = serial_get_char();		// 收幀計數
				if (nextChar != pack_counter)		// 幀計數是否正確
				{
					serial_put_char(XMODEM_CAN);	// 不正確,取消傳送
					serial_put_char(XMODEM_CAN);
					serial_put_char(XMODEM_CAN);
					serial_put_char(XMODEM_CAN);
					return (-1);
				}
				if (GetRecord(pack_counter, frame_data)) //收數據
				{
					fwrite(frame_data, XMODEM_DATA_SIZE);	// 寫入flash
					++pack_counter;							// 計數加1
					ntry = 0;				
					state = WAIT_SOH;						// 等下一個幀
					serial_put_char(XMODEM_ACK);			// 發送應答
				}
				else	// 收數據錯誤
				{
					if (++ntry >9)	// 錯誤次數超出限制
					{
						serial_put_char(XMODEM_CAN);	// 取消傳送
						serial_put_char(XMODEM_CAN);
						serial_put_char(XMODEM_CAN);
						serial_put_char(XMODEM_CAN);
						return (-1);
					}
					state = WAIT_SOH;
					serial_put_char(XMODEM_NAK);	// 請求重傳
				}
				break;

			default:
				break;
		}
	}
	return 0;
}