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freebsd/contrib/ntp/libntp/icom.c
2001-08-29 14:35:15 +00:00

324 lines
7.6 KiB
C

/*
* Program to control ICOM radios
*
* This is a ripoff of the utility routines in the ICOM software
* distribution. The only function provided is to load the radio
* frequency. All other parameters must be manually set before use.
*/
#include "icom.h"
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include "ntp_tty.h"
/*
* Scraps
*/
#define BMAX 50 /* max command length */
#define DICOM /dev/icom/ /* ICOM port link */
/*
* FSA definitions
*/
#define S_IDLE 0 /* idle */
#define S_HDR 1 /* header */
#define S_TX 2 /* address */
#define S_DATA 3 /* data */
#define S_ERROR 4 /* error */
/*
* Local function prototypes
*/
static void doublefreq P((double, u_char *, int));
static int sndpkt P((int, int, u_char *, u_char *));
static int sndoctet P((int, int));
static int rcvoctet P((int));
/*
* Local variables
*/
static int flags; /* trace flags */
static int state; /* fsa state */
/*
* icom_freq(fd, ident, freq) - load radio frequency
*/
int
icom_freq( /* returns 0 (ok), EIO (error) */
int fd, /* file descriptor */
int ident, /* ICOM radio identifier */
double freq /* frequency (MHz) */
)
{
u_char cmd[BMAX], rsp[BMAX];
int temp;
cmd[0] = V_SFREQ;
if (ident == IC735)
temp = 4;
else
temp = 5;
doublefreq(freq * 1e6, &cmd[1], temp);
temp = sndpkt(fd, ident, cmd, rsp);
if (temp < 1 || rsp[0] != ACK)
return (EIO);
return (0);
}
/*
* doublefreq(freq, y, len) - double to ICOM frequency with padding
*/
static void
doublefreq( /* returns void */
double freq, /* frequency */
u_char *x, /* radio frequency */
int len /* length (octets) */
)
{
int i;
char s1[11];
char *y;
sprintf(s1, " %10.0f", freq);
y = s1 + 10;
i = 0;
while (*y != ' ') {
x[i] = *y-- & 0x0f;
x[i] = x[i] | ((*y-- & 0x0f) << 4);
i++;
}
for (; i < len; i++)
x[i] = 0;
x[i] = FI;
}
/*
* Packet routines
*
* These routines send a packet and receive the response. If an error
* (collision) occurs on transmit, the packet is resent. If an error
* occurs on receive (timeout), all input to the terminating FI is
* discarded and the packet is resent. If the maximum number of retries
* is not exceeded, the program returns the number of octets in the user
* buffer; otherwise, it returns zero.
*
* ICOM frame format
*
* Frames begin with a two-octet preamble PR-PR followyd by the
* transceiver address RE, controller address TX, control code CN, zero
* or more data octets DA (depending on command), and terminator FI.
* Since the bus is bidirectional, every octet output is echoed on
* input. Every valid frame sent is answered with a frame in the same
* format, but with the RE and TX fields interchanged. The CN field is
* set to NAK if an error has occurred. Otherwise, the data are returned
* in this and following DA octets. If no data are returned, the CN
* octet is set to ACK.
*
* +------+------+------+------+------+--//--+------+
* | PR | PR | RE | TX | CN | DA | FI |
* +------+------+------+------+------+--//--+------+
*/
/*
* icom_open() - open and initialize serial interface
*
* This routine opens the serial interface for raw transmission; that
* is, character-at-a-time, no stripping, checking or monkeying with the
* bits. For Unix, an input operation ends either with the receipt of a
* character or a 0.5-s timeout.
*/
int
icom_init(
char *device, /* device name/link */
int speed, /* line speed */
int trace /* trace flags */ )
{
TTY ttyb;
int fd;
flags = trace;
fd = open(device, O_RDWR, 0777);
if (fd < 0)
return (fd);
tcgetattr(fd, &ttyb);
ttyb.c_iflag = 0; /* input modes */
ttyb.c_oflag = 0; /* output modes */
ttyb.c_cflag = IBAUD|CS8|CREAD|CLOCAL; /* control modes */
ttyb.c_lflag = 0; /* local modes */
ttyb.c_cc[VMIN] = 0; /* min chars */
ttyb.c_cc[VTIME] = 5; /* receive timeout */
cfsetispeed(&ttyb, (u_int)speed);
cfsetospeed(&ttyb, (u_int)speed);
tcsetattr(fd, TCSANOW, &ttyb);
return (fd);
}
/*
* sndpkt(r, x, y) - send packet and receive response
*
* This routine sends a command frame, which consists of all except the
* preamble octets PR-PR. It then listens for the response frame and
* returns the payload to the caller. The routine checks for correct
* response header format; that is, the length of the response vector
* returned to the caller must be at least 2 and the RE and TX octets
* must be interchanged; otherwise, the operation is retried up to
* the number of times specified in a global variable.
*
* The trace function, which is enabled by the P_TRACE bit of the global
* flags variable, prints all characters received or echoed on the bus
* preceded by a T (transmit) or R (receive). The P_ERMSG bit of the
* flags variable enables printing of bus error messages.
*
* Note that the first octet sent is a PAD in order to allow time for
* the radio to flush its receive buffer after sending the previous
* response. Even with this precaution, some of the older radios
* occasionally fail to receive a command and it has to be sent again.
*/
static int
sndpkt( /* returns octet count */
int fd, /* file descriptor */
int r, /* radio address */
u_char *cmd, /* command vector */
u_char *rsp /* response vector */
)
{
int i, j, temp;
(void)tcflush(fd, TCIOFLUSH);
for (i = 0; i < RETRY; i++) {
state = S_IDLE;
/*
* Transmit packet.
*/
if (flags & P_TRACE)
printf("icom T:");
sndoctet(fd, PAD); /* send header */
sndoctet(fd, PR);
sndoctet(fd, PR);
sndoctet(fd, r);
sndoctet(fd, TX);
for (j = 0; j < BMAX; j++) { /* send body */
if (sndoctet(fd, cmd[j]) == FI)
break;
}
while (rcvoctet(fd) != FI); /* purge echos */
if (cmd[0] == V_FREQT || cmd[0] == V_MODET)
return (0); /* shortcut for broadcast */
/*
* Receive packet. First, delete all characters
* preceeding a PR, then discard all PRs. Check that the
* RE and TX fields are correctly interchanged, then
* copy the remaining data and FI to the user buffer.
*/
if (flags & P_TRACE)
printf("\nicom R:");
j = 0;
while ((temp = rcvoctet(fd)) != FI) {
switch (state) {
case S_IDLE:
if (temp != PR)
continue;
state = S_HDR;
break;
case S_HDR:
if (temp == PR) {
continue;
} else if (temp != TX) {
if (flags & P_ERMSG)
printf(
"icom: TX error\n");
state = S_ERROR;
}
state = S_TX;
break;
case S_TX:
if (temp != r) {
if (flags & P_ERMSG)
printf(
"icom: RE error\n");
state = S_ERROR;
}
state = S_DATA;
break;
case S_DATA:
if (j >= BMAX ) {
if (flags & P_ERMSG)
printf(
"icom: buffer overrun\n");
state = S_ERROR;
j = 0;
}
rsp[j++] = (u_char)temp;
break;
case S_ERROR:
break;
}
}
if (flags & P_TRACE)
printf("\n");
if (j > 0) {
rsp[j++] = FI;
return (j);
}
}
if (flags & P_ERMSG)
printf("icom: retries exceeded\n");
return (0);
}
/*
* Interface routines
*
* These routines read and write octets on the bus. In case of receive
* timeout a FI code is returned. In case of output collision (echo
* does not match octet sent), the remainder of the collision frame
* (including the trailing FI) is discarded.
*/
/*
* sndoctet(fd, x) - send octet
*/
static int
sndoctet( /* returns octet */
int fd, /* file descriptor */
int x /* octet */
)
{
u_char y;
y = (u_char)x;
write(fd, &y, 1);
return (x);
}
/*
* rcvoctet(fd) - receive octet
*/
static int
rcvoctet( /* returns octet */
int fd /* file descriptor */
)
{
u_char y;
if (read(fd, &y, 1) < 1)
y = FI; /* come here if timeout */
if (flags & P_TRACE && y != PAD)
printf(" %02x", y);
return (y);
}
/* end program */