2 * This file is part of the libsigrok project.
4 * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
30 * Get a temperature value from a four-character buffer. The value is
31 * encoded in ASCII and the unit is deci-degrees (tenths of degrees).
33 static float parse_temperature(unsigned char *buf)
41 for (i = 0; i < 4; i++) {
46 sr_dbg("Double negative sign!");
52 if (buf[i] < '0' || buf[i] > '9') {
53 sr_dbg("Invalid digit '%.2x'!", buf[i]);
66 static void process_packet(struct sr_dev_inst *sdi, uint8_t *pkt, size_t len)
68 struct dev_context *devc;
69 struct sr_datafeed_packet packet;
70 struct sr_datafeed_analog analog;
71 struct sr_analog_encoding encoding;
72 struct sr_analog_meaning meaning;
73 struct sr_analog_spec spec;
78 if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
79 spew = sr_hexdump_new(pkt, len);
80 sr_spew("Got a packet, len %zu, bytes%s", len, spew->str);
81 sr_hexdump_free(spew);
83 if (len != PACKET_SIZE)
85 if (pkt[17] != SEP[0] || pkt[18] != SEP[1])
87 if (pkt[8] != '0' || pkt[16] != '1')
89 sr_dbg("Processing 19-byte packet.");
92 if (pkt[1] == NEG && pkt[2] == NEG && pkt[3] == NEG && pkt[4] == NEG)
93 /* No measurement: missing channel, empty storage location, ... */
96 temp = parse_temperature(&pkt[1]);
101 memset(&packet, 0, sizeof(packet));
102 sr_analog_init(&analog, &encoding, &meaning, &spec, 1);
103 analog.meaning->mq = SR_MQ_TEMPERATURE;
104 analog.meaning->mqflags = 0;
105 switch (pkt[5] - '0') {
107 analog.meaning->unit = SR_UNIT_CELSIUS;
110 analog.meaning->unit = SR_UNIT_FAHRENHEIT;
113 analog.meaning->unit = SR_UNIT_KELVIN;
116 /* We can still pass on the measurement, whatever it is. */
117 sr_dbg("Unknown unit 0x%.2x.", pkt[5]);
119 switch (pkt[13] - '0') {
122 analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 0));
126 analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 1));
131 analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 2));
132 analog.meaning->mqflags |= SR_MQFLAG_RELATIVE;
135 sr_err("Unknown channel 0x%.2x.", pkt[13]);
139 analog.num_samples = 1;
141 packet.type = SR_DF_ANALOG;
142 packet.payload = &analog;
143 sr_session_send(sdi, &packet);
144 g_slist_free(analog.meaning->channels);
149 * We count packets even if the measurement was invalid. This way
150 * a sample limit on "Memory" data source still works: Unused
151 * memory slots come through as "----" measurements.
154 sr_sw_limits_update_samples_read(&devc->limits, 1);
155 if (sr_sw_limits_check(&devc->limits))
156 sr_dev_acquisition_stop(sdi);
159 static int process_buffer(struct sr_dev_inst *sdi)
161 struct dev_context *devc;
166 * Specifically do not insist on finding the packet boundary at
167 * the end of the most recently received data chunk. Serial
168 * ports might involve hardware buffers (FIFO). We want to sync
169 * as fast as possible.
171 * Handle the synchronized situation first. Process complete
172 * packets that reside at the start of the buffer. Then fallback
173 * to incomplete or unaligned packets if the receive buffer
174 * still contains data bytes. (Depending on the bitrate and the
175 * poll interval, we may always end up in the manual search. But
176 * considering the update rate - two or three packets per second
177 * - this is not an issue.)
180 pkt = &devc->packet[0];
181 while (devc->packet_len >= PACKET_SIZE &&
182 pkt[PACKET_SIZE - 2] == SEP[0] &&
183 pkt[PACKET_SIZE - 1] == SEP[1]) {
184 process_packet(sdi, &pkt[0], PACKET_SIZE);
185 remain = devc->packet_len - PACKET_SIZE;
187 memmove(&pkt[0], &pkt[PACKET_SIZE], remain);
188 devc->packet_len -= PACKET_SIZE;
192 * The 'for' loop and the increment upon re-iteration after
193 * setting the loop var to zero is not an issue. The marker has
194 * two bytes, so effectively starting the search at offset 1 is
195 * fine for the specific packet layout.
197 for (idx = 0; idx < devc->packet_len; idx++) {
200 if (pkt[idx - 1] != SEP[0] || pkt[idx] != SEP[1])
202 /* Found a packet that spans up to and including 'idx'. */
204 process_packet(sdi, &pkt[0], idx);
205 remain = devc->packet_len - idx;
207 memmove(&pkt[0], &pkt[idx], remain);
208 devc->packet_len -= idx;
215 /* Gets invoked when RX data is available. */
216 static int ut32x_receive_data(struct sr_dev_inst *sdi)
218 struct dev_context *devc;
219 struct sr_serial_dev_inst *serial;
226 * Discard receive data when the buffer is exhausted. This shall
227 * allow to (re-)synchronize to the data stream when we find it
228 * in an arbitrary state. Drain more data from the serial port,
229 * and check the receive buffer for packets.
231 if (devc->packet_len == sizeof(devc->packet)) {
232 process_packet(sdi, &devc->packet[0], devc->packet_len);
233 devc->packet_len = 0;
235 len = sizeof(devc->packet) - devc->packet_len;
236 len = serial_read_nonblocking(serial,
237 &devc->packet[devc->packet_len], len);
241 devc->packet_len += len;
247 /* Gets periodically invoked by the glib main loop. */
248 SR_PRIV int ut32x_handle_events(int fd, int revents, void *cb_data)
250 struct sr_dev_inst *sdi;
251 struct sr_serial_dev_inst *serial;
263 if (revents & G_IO_IN)
264 ut32x_receive_data(sdi);
266 if (sdi->status == SR_ST_STOPPING) {
267 serial_source_remove(sdi->session, serial);
268 std_session_send_df_end(sdi);
269 sdi->status = SR_ST_ACTIVE;
271 /* Tell the device to stop sending data. */
273 serial_write_blocking(serial, &cmd, sizeof(cmd), 0);