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/*
* Copyright (C) 2003 Arnim Laeuger <arnim.laeuger@gmx.net>
* Issued under GPL. Originally part of an unpublished utility
* called sirf_ctrl. Contributed to gpsd by the author.
*
* Modified to not use stderr and so each function returns 0 on success,
* nonzero on failure. Alsso to use gpsd's own checksum and send code.
*/
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include "gpsd.h"
#include "sirf.h"
#ifdef __UNUSED__
/* These require binary mode */
#define HI(n) ((n) >> 8)
#define LO(n) ((n) & 0xff)
static u_int16_t crc_sirf(u_int8_t *msg) {
int pos = 0;
u_int16_t crc = 0;
int len;
len = (msg[2] << 8) | msg[3];
/* calculate CRC */
while (pos != len)
crc += msg[pos++ + 4];
crc &= 0x7fff;
/* enter CRC after payload */
msg[len + 4] = (u_int8_t)((crc & 0xff00) >> 8);
msg[len + 5] = (u_int8_t)( crc & 0x00ff);
return(crc);
}
int sirf_waas_ctrl(int ttyfd, int enable)
/* enable or disable WAAS */
{
u_int8_t msg[] = {0xa0, 0xa2, 0x00, 0x07,
0x85, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00,
0x00, 0x00, 0xb0, 0xb3};
msg[5] = (u_int8_t)enable;
crc_sirf(msg);
return (write(ttyfd, msg, 15) != 15);
}
int sirf_to_nmea(int ttyfd, int speed)
/* switch from binary to NMEA at specified baud */
{
u_int8_t msg[] = {0xa0, 0xa2, 0x00, 0x18,
0x81, 0x02,
0x01, 0x01, /* GGA */
0x00, 0x01, /* GLL */
0x01, 0x01, /* GSA */
0x05, 0x01, /* GSV */
0x01, 0x01, /* RMC */
0x00, 0x01, /* VTG */
0x00, 0x01, 0x00, 0x01,
0x00, 0x01, 0x00, 0x01,
0x12, 0xc0, /* 4800 bps */
0x00, 0x00, 0xb0, 0xb3};
msg[26] = HI(speed);
msg[27] = LO(speed);
crc_sirf(msg);
return (write(ttyfd, msg, 0x18+8) != 0x18+8);
}
int sirf_reset(int ttyfd)
/* reset GPS parameters */
{
u_int8_t msg[] = {0xa0, 0xa2, 0x00, 0x19,
0x81,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00,
0x0c,
0x04,
0x00, 0x00, 0xb0, 0xb3};
crc_sirf(msg);
return (write(ttyfd, msg, 0x19+8) != 0x19+8);
}
int sirf_dgps_source(int ttyfd, int source)
/* set source for DGPS corrections */
{
int i;
u_int8_t msg1[] = {0xa0, 0xa2, 0x00, 0x07,
0x85,
0x00, /* DGPS source */
0x00, 0x01, 0xe3, 0x34, /* 123.7 kHz */
0x00, /* auto bitrate */
0x00, 0x00, 0xb0, 0xb3};
u_int8_t msg2[] = {0xa0, 0xa2, 0x00, 0x03,
0x8a,
0x00, 0xff, /* auto, 255 sec */
0x00, 0x00, 0xb0, 0xb3};
u_int8_t msg3[] = {0xa0, 0xa2, 0x00, 0x09,
0x91,
0x00, 0x00, 0x12, 0xc0, /* 4800 baud */
0x08, /* 8 bits */
0x01, /* 1 Stop bit */
0x00, /* no parity */
0x00,
0x00, 0x00, 0xb0, 0xb3};
/*
* set DGPS source
*/
switch (source) {
case DGPS_SOURCE_NONE:
/* set no DGPS source */
msg1[5] = 0x00;
break;
case DGPS_SOURCE_INTERNAL:
/* set to internal DGPS beacon */
msg1[5] = 0x03;
break;
case DGPS_SOURCE_WAAS:
/* set to WAAS/EGNOS */
msg1[5] = 0x01;
for (i = 6; i < 11; i++)
msg1[i] = 0x00;
break;
case DGPS_SOURCE_EXTERNAL:
/* set to external RTCM input */
msg1[5] = 0x02;
break;
}
crc_sirf(msg1);
if (write(ttyfd, msg1, 0x07+8) != 0x07+8)
return 1;
/*
* set DGPS control to auto
*/
if (source != DGPS_SOURCE_WAAS) {
crc_sirf(msg2);
if (write(ttyfd, msg2, 0x03+8) != 0x03+8)
return 2;
}
/*
* set DGPS port
*/
if (source == DGPS_SOURCE_EXTERNAL) {
crc_sirf(msg3);
if (write(ttyfd, msg3, 0x09+8) == 0x09+8)
return 3;
}
return(0);
}
int sirf_nav_lib (int ttyfd, int enable)
/* set single-channel mode */
{
u_int8_t msg_1[] = {0xa0, 0xa2, 0x00, 0x19,
0x80,
0x00, 0x00, 0x00, 0x00, /* ECEF X */
0x00, 0x00, 0x00, 0x00, /* ECEF Y */
0x00, 0x00, 0x00, 0x00, /* ECEF Z */
0x00, 0x00, 0x00, 0x00, /* Clock Offset */
0x00, 0x00, 0x00, 0x00, /* Time of Week */
0x00, 0x00, /* Week Number */
0x0c, /* Channels */
0x00, /* Reset Config */
0x00, 0x00, 0xb0, 0xb3};
if (enable == 1)
msg_1[28] = 0x10;
crc_sirf(msg_1);
return (write(ttyfd, msg_1, 0x19+8) != 0x19+8);
}
int sirf_power_mask(int ttyfd, int low)
/* set dB cutoff level below which satellite info will be ignored */
{
u_int8_t msg[] = {0xa0, 0xa2, 0x00, 0x03,
0x8c, 0x1c, 0x1c,
0x00, 0x00, 0xb0, 0xb3};
if (low == 1)
msg[6] = 0x14;
crc_sirf(msg);
return (write(ttyfd, msg, 0x03+8) != 0x03+8);
}
int sirf_power_save(int ttyfd, int enable)
/* enable/disable SiRF trickle-power mode */
{
u_int8_t msg[] = {0xa0, 0xa2, 0x00, 0x09,
0x97,
0x00, 0x00,
0x03, 0xe8,
0x00, 0x00, 0x00, 0xc8,
0x00, 0x00, 0xb0, 0xb3};
if (enable == 1) {
/* power save: duty cycle is 20% */
msg[7] = 0x00;
msg[8] = 0xc8;
}
crc_sirf(msg);
return (write(ttyfd, msg, 0x09+8) != 0x09+8);
}
#endif /* __UNUSED __ */
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