//--------------------------------------------------------------------------------
void NavisInitProcedure()
{
int crc, len;
char o;
char needsCrc;
char buf[10];

struct timeval t;
t.tv_sec =0;
t.tv_usec = 250E+3;
if (!TimerPast (navis.initTimer, t))
	return;

GetCurrentTime(&navis.initTimer);

len=1; // default value
needsCrc=1;// default value

//10 17 01 10 03 -= example of requesting 0x17 message with 1 hz

switch(navis.initStage)
	{
	// x- request, o - response
	case 0:
		buf[0]=0xb2;
		o=0xC2;
		buf[1]=2+4; // CRC enable, geodetic coords, height above ellipsoid
		buf[2]=0; //
		len=2;
		needsCrc=0;
		break;
	case 1:
		buf[0]=0x17;
		o=0x42; // requests for 0x42 message
		buf[1]=1;
		break;
	case 2:
		buf[0]=0x24;
		o=0x52; // requests for 0x52 message
		buf[1]=1;
		break;
	case 3:
		buf[0]=0xf4;
		o=0x70; // response: 0x70, 0x4A, 0x4B, 0xF5, 0xF6, 0xF7 with different intervals
		buf[1]=10; // частоты выдачи задается в 100 милисек интервалах
		break;
	case 4:
		buf[0]=0x27;
		o=0x88; // response: 0x88
		buf[1]=1; //
		break;
	case 5:
		buf[0]=0x0b;
		o=0x50;
		buf[1]=1;
		break;
		/* not using
	case 6:
		{
		x=0x2b;
		o=0x4b; // response: 0x4b
		byte1=10; //
		break;
		*/
	default:
		navis.initStage=-1;
		printf ("Navis initialize finished\n");
		return;
	} //^^^ switch

printf("initializing Navis, stage:%d, sending msg: 0x%02X and waiting for: 0x%02X...\n", navis.initStage, buf[0], o);
navis.initStage++;

GpsWrite(0x10);
crc=0;
for (int j=0; j<=len; j++)
	{
	GpsWrite(buf[j]);
	crc=UpdCrc(crc, buf[j]);
	}
if (needsCrc)
	{
	GpsWrite(0x10);
	GpsWrite(0xFF);
	GpsWrite(crc & 0xFF);
	GpsWrite((crc >> 8) & 0xFF);
	}

GpsWrite(0x10);
GpsWrite(0x03);
}