xmodem.c

自己写的一个基于kb9202开发板的bootloader

#include "at91rm9200.h"
#include "xmodem.h"

static int ticks,timeout,state,seconds,times;

int getc_non_block(unsigned char* c){
	dbgu_reg_p dbgu = (dbgu_reg_s *)DBGU_BASE;
	
	ticks = 0;
	timeout = 0;
	while(1){
		if( dbgu->dbgu_sr & (USART_RXRDY) ){
			*c = (unsigned char)(dbgu->dbgu_rhr & 0xff);
			if( state==XM_WAIT ){
				seconds=0;
				times=0;
			}
			ticks=0;
			return 1;
		}
		if( timeout ){
			timeout = 0;
			if( state==XM_WAIT ){
				seconds++;
				if( seconds==3 ){
					seconds = 0;
					times++;
					if( times==2 ){
						times = 0;
						return -1;
					}
				}
			} else
				return 0;
		}
	}
}
	
void delay_s(int second){
	while(second--){
		ticks=0;
		timeout=0;
		while(timeout==0);
	}
}

int x_receive(unsigned* mem_start){
	x_packet packet;
	unsigned *p = (unsigned *)&packet + 1;

	unsigned char nextChar,blk_num=1;
	int got_pkt=0,i,j,k=30;
	
	ticks=timeout=seconds=times=0;
	state=XM_START;

	while( 1 ){
		if( got_pkt ){
			blk_num++;
			for( i=0;i<32;i++ )
				*mem_start++ = p[i];
			got_pkt = 0;
			put_char( XM_ACK );
		} else
			put_char( XM_NAK );
recv_pkt:
//soh
		i = getc_non_block(&nextChar);
		if( i==-1 ){
			put_char( XM_CAN );
			return 0;
		} else if( i==0 ){
			if(k-->0)
				continue;
			else{
				put_char(XM_CAN);
				return 0;
			}
		}
		if( nextChar==XM_EOT ){
			put_char( XM_ACK );
			return 1;
		} else if( nextChar==XM_SOH ){
			packet.soh = nextChar;
			state = XM_RECV;
		} else {
			state = XM_WAIT;
			delay_s(1);
			continue;
		}
//blk
		i = getc_non_block(&nextChar);
		if( i==0 ){
			state = XM_WAIT;
			continue;
		}
		if( nextChar==blk_num-1 ){
			state = XM_WAIT;
			delay_s(1);
			got_pkt=0;
			put_char(XM_ACK);
			goto recv_pkt;
			continue;
		} else if( nextChar==blk_num )
			packet.blk = blk_num;
		else{
			put_char( XM_CAN );
			return 0;
		}
//blk_comp
		i = getc_non_block(&nextChar);
		if( i==0 ){
			state = XM_WAIT;
			continue;
		}
		if( nextChar!=0xff-packet.blk ){
			state = XM_WAIT;
			delay_s(1);
			continue;
		} else
			packet.blk_comp = nextChar;
//data[128]
		for(j=0;j<128;j++){
			i = getc_non_block(&nextChar);
			if( i==0 ){
				state = XM_WAIT;
				break;
			}
			packet.data[j] = nextChar;
		}
		if( j<128 )
			continue;
//checksum
		i = getc_non_block(&nextChar);
		if( i==0 ){
			state=XM_WAIT;
			continue;
		}
		for(i=j=0;j<128;j++)
			i+=packet.data[j];
		i = i&0xff;
		if(i==nextChar)
			got_pkt = 1;
		state = XM_WAIT;
	}
}

void int_tc(){
	tc_reg_p tc0 = (tc_reg_s *)TC0_BASE;
	int value = tc0->tcc[0].tc_sr;
	ticks++;
	if( ticks==6 ){
		ticks=0;
		timeout=1;
	}
}