hardware/colead-slm/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
   5  *
   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.
  10  *
  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.
  15  *
  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/>.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <glib.h>
  22 #include "libsigrok.h"
  23 #include "libsigrok-internal.h"
  24 #include "protocol.h"
  25 #include <errno.h>
  26 #include <string.h>
  27
  28
  29 static void process_packet(const struct sr_dev_inst *sdi)
  30 {
  31         struct dev_context *devc;
  32         struct sr_datafeed_packet packet;
  33         struct sr_datafeed_analog analog;
  34         GString *dbg;
  35         float fvalue;
  36         int checksum, mode, i;
  37
  38         devc = sdi->priv;
  39         if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
  40                 dbg = g_string_sized_new(128);
  41                 g_string_printf(dbg, "received packet:");
  42                 for (i = 0; i < 10; i++)
  43                         g_string_append_printf(dbg, " %.2x", (devc->buf)[i]);
  44                 sr_spew("%s", dbg->str);
  45                 g_string_free(dbg, TRUE);
  46         }
  47
  48         if (devc->buf[0] != 0x08 || devc->buf[1] != 0x04) {
  49                 sr_dbg("invalid packet header.");
  50                 return;
  51         }
  52
  53         if (devc->buf[8] != 0x01) {
  54                 sr_dbg("invalid measurement.");
  55                 return;
  56         }
  57
  58         checksum = 0;
  59         for (i = 0; i < 9; i++)
  60                 checksum += devc->buf[i];
  61         if ((checksum & 0xff) != devc->buf[9]) {
  62                 sr_dbg("invalid packet checksum.");
  63                 return;
  64         }
  65
  66         fvalue = 0.0;
  67         for (i = 3; i < 8; i++) {
  68                 if (devc->buf[i] > 0x09)
  69                         continue;
  70                 fvalue *= 10;
  71                 fvalue += devc->buf[i];
  72         }
  73         fvalue /= 10;
  74
  75         memset(&analog, 0, sizeof(struct sr_datafeed_analog));
  76         analog.mq = SR_MQ_SOUND_PRESSURE_LEVEL;
  77         analog.unit = SR_UNIT_DECIBEL_SPL;
  78         analog.num_samples = 1;
  79         analog.data = &fvalue;
  80
  81         /* High nibble should only have 0x01 or 0x02. */
  82         mode = (devc->buf[2] >> 4) & 0x0f;
  83         if (mode == 0x02)
  84                 analog.mqflags |= SR_MQFLAG_HOLD;
  85         else if (mode != 0x01) {
  86                 sr_dbg("unknown measurement mode 0x%.2x", mode);
  87                 return;
  88         }
  89
  90         /* Low nibble has 14 combinations of direct/long-term average,
  91          * time scale of that average, frequency weighting, and time
  92          * weighting. */
  93         mode = devc->buf[2] & 0x0f;
  94         switch (mode) {
  95                 case 0x0:
  96                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_A \
  97                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
  98                         break;
  99                 case 0x1:
 100                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 101                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 102                         break;
 103                 case 0x2:
 104                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_C \
 105                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
 106                         break;
 107                 case 0x3:
 108                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_C \
 109                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 110                         break;
 111                 case 0x4:
 112                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT \
 113                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
 114                         break;
 115                 case 0x5:
 116                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT \
 117                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 118                         break;
 119                 case 0x6:
 120                         analog.mqflags |= SR_MQFLAG_SPL_PCT_OVER_ALARM \
 121                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 122                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
 123                         break;
 124                 case 0x7:
 125                         analog.mqflags |= SR_MQFLAG_SPL_PCT_OVER_ALARM \
 126                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 127                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 128                         break;
 129                 case 0x8:
 130                         /* 10-second mean, but we don't have MQ flags to express it. */
 131                         analog.mqflags |= SR_MQFLAG_SPL_LAT \
 132                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 133                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
 134                         break;
 135                 case 0x9:
 136                         /* Mean over a time period between 11 seconds and 24 hours.
 137                          * Which is so silly that there's no point in expressing
 138                          * either this or the previous case.  */
 139                         analog.mqflags |= SR_MQFLAG_SPL_LAT \
 140                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 141                                         | SR_MQFLAG_SPL_TIME_WEIGHT_F;
 142                         break;
 143                 case 0xa:
 144                         /* 10-second mean. */
 145                         analog.mqflags |= SR_MQFLAG_SPL_LAT \
 146                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 147                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 148                         break;
 149                 case 0xb:
 150                         /* Mean over a time period between 11 seconds and 24 hours. */
 151                         analog.mqflags |= SR_MQFLAG_SPL_LAT \
 152                                         | SR_MQFLAG_SPL_FREQ_WEIGHT_A \
 153                                         | SR_MQFLAG_SPL_TIME_WEIGHT_S;
 154                         break;
 155                 case 0xc:
 156                         /* Internal calibration on 1kHz sine at 94dB, not useful
 157                          * to anything but the device. */
 158                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT;
 159                         break;
 160                 case 0xd:
 161                         /* Internal calibration on 1kHz sine at 94dB, not useful
 162                          * to anything but the device. */
 163                         analog.mqflags |= SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT;
 164                         break;
 165                 default:
 166                         sr_dbg("unknown configuration 0x%.2x", mode);
 167                         return;
 168                         break;
 169         }
 170
 171         packet.type = SR_DF_ANALOG;
 172         packet.payload = &analog;
 173         sr_session_send(devc->cb_data, &packet);
 174
 175         devc->num_samples++;
 176
 177 }
 178
 179 SR_PRIV int colead_slm_receive_data(int fd, int revents, void *cb_data)
 180 {
 181         const struct sr_dev_inst *sdi;
 182         struct dev_context *devc;
 183         int len;
 184         char buf[128];
 185
 186         (void)fd;
 187
 188         if (!(sdi = cb_data))
 189                 return TRUE;
 190
 191         if (!(devc = sdi->priv))
 192                 return TRUE;
 193
 194         if (revents != G_IO_IN)
 195                 /* Timeout event. */
 196                 return TRUE;
 197
 198         if (devc->state == IDLE) {
 199                 if (serial_read(devc->serial, buf, 128) != 1 || buf[0] != 0x10)
 200                         /* Nothing there, or caught the tail end of a previous packet,
 201                          * or some garbage. Unless it's a single "data ready" byte,
 202                          * we don't want it. */
 203                         return TRUE;
 204                 /* Got 0x10, "measurement ready". */
 205                 if (serial_write(devc->serial, "\x20", 1) == -1)
 206                         sr_err("unable to send command: %s", strerror(errno));
 207                 else {
 208                         devc->state = COMMAND_SENT;
 209                         devc->buflen = 0;
 210                 }
 211         } else {
 212                 len = serial_read(devc->serial, devc->buf + devc->buflen,
 213                                 10 - devc->buflen);
 214                 if (len < 1)
 215                         return TRUE;
 216                 devc->buflen += len;
 217                 if (devc->buflen > 10) {
 218                         sr_dbg("buffer overrun");
 219                         devc->state = IDLE;
 220                         return TRUE;
 221                 }
 222                 if (devc->buflen == 10) {
 223                         /* If we got here, we're sure the device sent a "data ready"
 224                          * notification, we asked for data, and got it. */
 225                         process_packet(sdi);
 226                         devc->state = IDLE;
 227                 }
 228         }
 229
 230         return TRUE;
 231 }
 232