xref: /freebsd/contrib/ntp/libntp/icom.c (revision 17d6c636720d00f77e5d098daf4c278f89d84f7b)
1 /*
2  * Program to control ICOM radios
3  *
4  * This is a ripoff of the utility routines in the ICOM software
5  * distribution. The only function provided is to load the radio
6  * frequency. All other parameters must be manually set before use.
7  */
8 #include "icom.h"
9 #include <unistd.h>
10 #include <stdio.h>
11 #include <fcntl.h>
12 #include <errno.h>
13 
14 #include "ntp_tty.h"
15 
16 /*
17  * Scraps
18  */
19 #define BMAX 50			/* max command length */
20 #define DICOM /dev/icom/	/* ICOM port link */
21 
22 /*
23  * FSA definitions
24  */
25 #define S_IDLE	0		/* idle */
26 #define S_HDR	1		/* header */
27 #define S_TX	2		/* address */
28 #define S_DATA	3		/* data */
29 #define S_ERROR	4		/* error */
30 
31 /*
32  * Local function prototypes
33  */
34 static void doublefreq		P((double, u_char *, int));
35 static int sndpkt		P((int, int, u_char *, u_char *));
36 static int sndoctet		P((int, int));
37 static int rcvoctet		P((int));
38 
39 /*
40  * Local variables
41  */
42 static int flags;		/* trace flags */
43 static int state;		/* fsa state */
44 
45 
46 /*
47  * icom_freq(fd, ident, freq) - load radio frequency
48  */
49 int
50 icom_freq(			/* returns 0 (ok), EIO (error) */
51 	int fd,			/* file descriptor */
52 	int ident,		/* ICOM radio identifier */
53 	double freq		/* frequency (MHz) */
54 	)
55 {
56 	u_char cmd[BMAX], rsp[BMAX];
57 	int temp;
58 	cmd[0] = V_SFREQ;
59 	if (ident == IC735)
60 		temp = 4;
61 	else
62 		temp = 5;
63 	doublefreq(freq * 1e6, &cmd[1], temp);
64 	temp = sndpkt(fd, ident, cmd, rsp);
65 	if (temp < 1 || rsp[0] != ACK)
66 		return (EIO);
67 	return (0);
68 }
69 
70 
71 /*
72  * doublefreq(freq, y, len) - double to ICOM frequency with padding
73  */
74 static void
75 doublefreq(			/* returns void */
76 	double freq,		/* frequency */
77 	u_char *x,		/* radio frequency */
78 	int len			/* length (octets) */
79 	)
80 {
81 	int i;
82 	char s1[11];
83 	char *y;
84 
85 	sprintf(s1, " %10.0f", freq);
86 	y = s1 + 10;
87 	i = 0;
88 	while (*y != ' ') {
89 		x[i] = *y-- & 0x0f;
90 		x[i] = x[i] | ((*y-- & 0x0f) << 4);
91 		i++;
92 	}
93 	for (; i < len; i++)
94 		x[i] = 0;
95 	x[i] = FI;
96 }
97 
98 
99 /*
100  * Packet routines
101  *
102  * These routines send a packet and receive the response. If an error
103  * (collision) occurs on transmit, the packet is resent. If an error
104  * occurs on receive (timeout), all input to the terminating FI is
105  * discarded and the packet is resent. If the maximum number of retries
106  * is not exceeded, the program returns the number of octets in the user
107  * buffer; otherwise, it returns zero.
108  *
109  * ICOM frame format
110  *
111  * Frames begin with a two-octet preamble PR-PR followyd by the
112  * transceiver address RE, controller address TX, control code CN, zero
113  * or more data octets DA (depending on command), and terminator FI.
114  * Since the bus is bidirectional, every octet output is echoed on
115  * input. Every valid frame sent is answered with a frame in the same
116  * format, but with the RE and TX fields interchanged. The CN field is
117  * set to NAK if an error has occurred. Otherwise, the data are returned
118  * in this and following DA octets. If no data are returned, the CN
119  * octet is set to ACK.
120  *
121  *	+------+------+------+------+------+--//--+------+
122  *	|  PR  |  PR  |  RE  |  TX  |  CN  |  DA  |  FI  |
123  *	+------+------+------+------+------+--//--+------+
124  */
125 /*
126  * icom_open() - open and initialize serial interface
127  *
128  * This routine opens the serial interface for raw transmission; that
129  * is, character-at-a-time, no stripping, checking or monkeying with the
130  * bits. For Unix, an input operation ends either with the receipt of a
131  * character or a 0.5-s timeout.
132  */
133 int
134 icom_init(
135 	char *device,		/* device name/link */
136 	int speed,		/* line speed */
137 	int trace		/* trace flags */	)
138 {
139 	TTY ttyb;
140 	int fd;
141 
142 	flags = trace;
143 	fd = open(device, O_RDWR, 0777);
144 	if (fd < 0)
145 		return (fd);
146 	tcgetattr(fd, &ttyb);
147 	ttyb.c_iflag = 0;	/* input modes */
148 	ttyb.c_oflag = 0;	/* output modes */
149 	ttyb.c_cflag = IBAUD|CS8|CREAD|CLOCAL;	/* control modes */
150 	ttyb.c_lflag = 0;	/* local modes */
151 	ttyb.c_cc[VMIN] = 0;	/* min chars */
152 	ttyb.c_cc[VTIME] = 5;	/* receive timeout */
153 	cfsetispeed(&ttyb, (u_int)speed);
154 	cfsetospeed(&ttyb, (u_int)speed);
155 	tcsetattr(fd, TCSANOW, &ttyb);
156 	return (fd);
157 }
158 
159 
160 /*
161  * sndpkt(r, x, y) - send packet and receive response
162  *
163  * This routine sends a command frame, which consists of all except the
164  * preamble octets PR-PR. It then listens for the response frame and
165  * returns the payload to the caller. The routine checks for correct
166  * response header format; that is, the length of the response vector
167  * returned to the caller must be at least 2 and the RE and TX octets
168  * must be interchanged; otherwise, the operation is retried up to
169  * the number of times specified in a global variable.
170  *
171  * The trace function, which is enabled by the P_TRACE bit of the global
172  * flags variable, prints all characters received or echoed on the bus
173  * preceded by a T (transmit) or R (receive). The P_ERMSG bit of the
174  * flags variable enables printing of bus error messages.
175  *
176  * Note that the first octet sent is a PAD in order to allow time for
177  * the radio to flush its receive buffer after sending the previous
178  * response. Even with this precaution, some of the older radios
179  * occasionally fail to receive a command and it has to be sent again.
180  */
181 static int
182 sndpkt(				/* returns octet count */
183 	int fd,			/* file descriptor */
184 	int r,			/* radio address */
185 	u_char *cmd,		/* command vector */
186 	u_char *rsp		/* response vector */
187 	)
188 {
189 	int i, j, temp;
190 
191 	(void)tcflush(fd, TCIOFLUSH);
192 	for (i = 0; i < RETRY; i++) {
193 		state = S_IDLE;
194 
195 		/*
196 		 * Transmit packet.
197 		 */
198 		if (flags & P_TRACE)
199 			printf("icom T:");
200 		sndoctet(fd, PAD);	/* send header */
201 		sndoctet(fd, PR);
202 		sndoctet(fd, PR);
203 		sndoctet(fd, r);
204 		sndoctet(fd, TX);
205 		for (j = 0; j < BMAX; j++) { /* send body */
206 			if (sndoctet(fd, cmd[j]) == FI)
207 				break;
208 		}
209 		while (rcvoctet(fd) != FI); /* purge echos */
210 		if (cmd[0] == V_FREQT || cmd[0] == V_MODET)
211 			return (0);	/* shortcut for broadcast */
212 
213 		/*
214 		 * Receive packet. First, delete all characters
215 		 * preceeding a PR, then discard all PRs. Check that the
216 		 * RE and TX fields are correctly interchanged, then
217 		 * copy the remaining data and FI to the user buffer.
218 		 */
219 		if (flags & P_TRACE)
220 			printf("\nicom R:");
221 		j = 0;
222 		while ((temp = rcvoctet(fd)) != FI) {
223 			switch (state) {
224 
225 			case S_IDLE:
226 				if (temp != PR)
227 					continue;
228 				state = S_HDR;
229 				break;
230 
231 			case S_HDR:
232 				if (temp == PR) {
233 					continue;
234 				} else if (temp != TX) {
235 					if (flags & P_ERMSG)
236 						printf(
237 						    "icom: TX error\n");
238 					state = S_ERROR;
239 				}
240 				state = S_TX;
241 				break;
242 
243 			case S_TX:
244 				if (temp != r) {
245 					if (flags & P_ERMSG)
246 						printf(
247 						    "icom: RE error\n");
248 					state = S_ERROR;
249 				}
250 				state = S_DATA;
251 				break;
252 
253 			case S_DATA:
254 				if (j >= BMAX ) {
255 					if (flags & P_ERMSG)
256 						printf(
257 					    "icom: buffer overrun\n");
258 					state = S_ERROR;
259 					j = 0;
260 				}
261 				rsp[j++] = (u_char)temp;
262 				break;
263 
264 			case S_ERROR:
265 				break;
266 			}
267 		}
268 		if (flags & P_TRACE)
269 			printf("\n");
270 		if (j > 0) {
271 			rsp[j++] = FI;
272 			return (j);
273 		}
274 	}
275 	if (flags & P_ERMSG)
276 		printf("icom: retries exceeded\n");
277 	return (0);
278 }
279 
280 
281 /*
282  * Interface routines
283  *
284  * These routines read and write octets on the bus. In case of receive
285  * timeout a FI code is returned. In case of output collision (echo
286  * does not match octet sent), the remainder of the collision frame
287  * (including the trailing FI) is discarded.
288  */
289 /*
290  * sndoctet(fd, x) - send octet
291  */
292 static int
293 sndoctet(			/* returns octet */
294 	int fd,			/* file descriptor */
295 	int x			/* octet */
296 	)
297 {
298 	u_char y;
299 
300 	y = (u_char)x;
301 	write(fd, &y, 1);
302 	return (x);
303 }
304 
305 
306 /*
307  * rcvoctet(fd) - receive octet
308  */
309 static int
310 rcvoctet(			/* returns octet */
311 	int fd			/* file descriptor */
312 	)
313 {
314 	u_char y;
315 
316 	if (read(fd, &y, 1) < 1)
317 		y = FI;		/* come here if timeout */
318 	if (flags & P_TRACE && y != PAD)
319 		printf(" %02x", y);
320 	return (y);
321 }
322 
323 /* end program */
324