irlap.c

这个是从国外弄到的一个红外协议栈

/*
  Copyright (C) 2002-2003 Gerd Rausch, BlauLogic (http://blaulogic.com)
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:

  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.

  3. Except as contained in this notice, neither the name of BlauLogic
     nor the name(s) of the author(s) may be used to endorse or promote
     products derived from this software without specific prior written
     permission.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHOR(S) OR BLAULOGIC BE LIABLE FOR ANY CLAIM,
  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
  THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include <string.h>

#include "irlap.h"
#include "irphy.h"

#define IRLAP_TIMEOUT1			500
#define IRLAP_TIMEOUT2			20

#define IRLAP_PSEUDO_RANDOM_DEV_ADDR	0x18021967

#define IRLAP_PAR_BAUD_RATE_VAL		0x02 /* 9600 bps */
#define IRLAP_PAR_MAX_TURN_TIME_VAL	0x01 /* 500 ms */
#define IRLAP_PAR_DATA_SIZE_VAL		((IRLAP_DATA_SIZE-1)>>5)
#define IRLAP_PAR_WINDOW_SIZE_VAL	0x01 /* 1 frame */
#define IRLAP_PAR_ADD_BOFS_VAL		0x80 /* 0 BOFs */
#define IRLAP_PAR_MIN_TURN_TIME_VAL	0x80 /* 0 ms */
#define IRLAP_PAR_DISC_TIME_VAL		0x01 /* 3 s */

#define IRLAP_XBOF_COUNT		10

#define IRLAP_XBOF			0xFF
#define IRLAP_BOF			0xC0
#define IRLAP_EOF			0xC1
#define IRLAP_CE			0x7D
#define IRLAP_TRANS			0x20
#define IRLAP_FCS_INIT			0xFF
#define IRLAP_FCS_GOOD0			0xB8
#define IRLAP_FCS_GOOD1			0xF0

static inline void send_byte(uint8_t v)
{
  if(v==IRLAP_BOF || v==IRLAP_EOF || v==IRLAP_CE) {
    irphy_send(IRLAP_CE);
    irphy_send(v^IRLAP_TRANS);
  } else
    irphy_send(v);
}

static IrLAP_Neg_Param *set_neg_param_1(IrLAP_Neg_Param *param_p, uint8_t id, uint8_t value)
{
  param_p->id=id;
  param_p->len=1;
  param_p->value[0]=value;

  return (IrLAP_Neg_Param *)((uint8_t *)param_p+sizeof(IrLAP_Neg_Param)+param_p->len);
}

uint16_t irlap_append_neg_params(uint8_t *info_p)
{
  IrLAP_Neg_Param *param_p;

  param_p=(IrLAP_Neg_Param *)info_p;

  param_p=set_neg_param_1(param_p, IRLAP_PAR_BAUD_RATE, IRLAP_PAR_BAUD_RATE_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_MAX_TURN_TIME, IRLAP_PAR_MAX_TURN_TIME_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_DATA_SIZE, IRLAP_PAR_DATA_SIZE_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_WINDOW_SIZE, IRLAP_PAR_WINDOW_SIZE_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_ADD_BOFS, IRLAP_PAR_ADD_BOFS_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_MIN_TURN_TIME, IRLAP_PAR_MIN_TURN_TIME_VAL);
  param_p=set_neg_param_1(param_p, IRLAP_PAR_DISC_TIME, IRLAP_PAR_DISC_TIME_VAL);

  return (uint8_t *)param_p-info_p;
}

uint8_t irlap_matching_dest_addr(IrLAP_Context *context_p, IrLAP_Device_Addr addr_p)
{
  return
    memcmp(addr_p, context_p->dev_addr, sizeof(IrLAP_Device_Addr))==0 ||
    (addr_p[0]==0xFF && addr_p[1]==0xFF && addr_p[2]==0xFF && addr_p[3]==0xFF);
}

void irlap_init_context(IrLAP_Context *context_p)
{
  context_p->dev_addr[0]=(uint8_t)IRLAP_PSEUDO_RANDOM_DEV_ADDR;
  context_p->dev_addr[1]=(uint8_t)(IRLAP_PSEUDO_RANDOM_DEV_ADDR>>8);
  context_p->dev_addr[2]=(uint8_t)(IRLAP_PSEUDO_RANDOM_DEV_ADDR>>16);
  context_p->dev_addr[3]=(uint8_t)(IRLAP_PSEUDO_RANDOM_DEV_ADDR>>24);
  context_p->conn_addr=IRLAP_ADDR_NULL;
  context_p->vr=0;
  context_p->vs=0;
}

void irlap_send_frame(IrLAP_Frame *frame_p, uint16_t size)
{
  uint16_t i;
  uint8_t fcs0, fcs1, v;

  for(i=0; i<IRLAP_XBOF_COUNT; i++)
    irphy_send(IRLAP_XBOF);

  irphy_send(IRLAP_BOF);

  fcs0=IRLAP_FCS_INIT;
  fcs1=IRLAP_FCS_INIT;
  for(i=0; i<size; i++) {
    v=((uint8_t *)frame_p)[i];
    send_byte(v);

    v^=fcs0;
    fcs0=fcs1;
    fcs1=v;

    fcs1^=fcs1<<4;
    fcs0^=fcs1>>4;
    fcs0^=fcs1<<3;
    fcs1^=fcs1>>5;
  }

  send_byte(~fcs0);
  send_byte(~fcs1);

  irphy_send(IRLAP_EOF);
}

int16_t irlap_receive_frame(IrLAP_Frame *frame_p)
{
  int16_t n;
  uint8_t fcs0, fcs1, v;

  do {
    if(!irphy_wait(IRLAP_TIMEOUT1))
      return -1;
  } while(irphy_receive()!=IRLAP_BOF);
  
  fcs0=IRLAP_FCS_INIT;
  fcs1=IRLAP_FCS_INIT;
  n=0;
  while(n<sizeof(IrLAP_Frame)) {
    if(!irphy_wait(IRLAP_TIMEOUT2))
      return -1;
    v=irphy_receive();

    if(v==IRLAP_BOF) {
      if(n>0)
	return -1;
      continue;
    }

    if(v==IRLAP_EOF) {
      if(n<2 || fcs0!=IRLAP_FCS_GOOD0 || fcs1!=IRLAP_FCS_GOOD1)
	return -1;
      return n-2;
    }

    if(v==IRLAP_CE) {
      if(!irphy_wait(IRLAP_TIMEOUT2))
	return -1;
      v=irphy_receive() ^ IRLAP_TRANS;
    }

    ((uint8_t *)frame_p)[n++]=v;

    v^=fcs0;
    fcs0=fcs1;
    fcs1=v;

    fcs1^=fcs1<<4;
    fcs0^=fcs1>>4;
    fcs0^=fcs1<<3;
    fcs1^=fcs1>>5;
  }

  return -1;
}