src/hardware/uni-t-ut32x/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2013 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 <config.h>
  21 #include <string.h>
  22 #include <math.h>
  23 #include "protocol.h"
  24
  25 #define SEP     "\r\n"
  26 #define BLANK   ':'
  27 #define NEG     ';'
  28
  29 /*
  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).
  32  */
  33 static float parse_temperature(unsigned char *buf)
  34 {
  35         float temp;
  36         int i;
  37         gboolean negative;
  38
  39         negative = FALSE;
  40         temp = 0.0;
  41         for (i = 0; i < 4; i++) {
  42                 if (buf[i] == BLANK)
  43                         continue;
  44                 if (buf[i] == NEG) {
  45                         if (negative) {
  46                                 sr_dbg("Double negative sign!");
  47                                 return NAN;
  48                         }
  49                         negative = TRUE;
  50                         continue;
  51                 }
  52                 if (buf[i] < '0' || buf[i] > '9') {
  53                         sr_dbg("Invalid digit '%.2x'!", buf[i]);
  54                         return NAN;
  55                 }
  56                 temp *= 10;
  57                 temp += buf[i] - '0';
  58         }
  59         temp /= 10;
  60         if (negative)
  61                 temp = -temp;
  62
  63         return temp;
  64 }
  65
  66 static void process_packet(struct sr_dev_inst *sdi)
  67 {
  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;
  74         GString *spew;
  75         float temp;
  76         int i;
  77         gboolean is_valid;
  78
  79         devc = sdi->priv;
  80         sr_dbg("Received full 19-byte packet.");
  81         if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
  82                 spew = g_string_sized_new(60);
  83                 for (i = 0; i < devc->packet_len; i++)
  84                         g_string_append_printf(spew, "%.2x ", devc->packet[i]);
  85                 sr_spew("%s", spew->str);
  86                 g_string_free(spew, TRUE);
  87         }
  88
  89         is_valid = TRUE;
  90         if (devc->packet[1] == NEG && devc->packet[2] == NEG
  91                         && devc->packet[3] == NEG && devc->packet[4] == NEG)
  92                 /* No measurement: missing channel, empty storage location, ... */
  93                 is_valid = FALSE;
  94
  95         temp = parse_temperature(devc->packet + 1);
  96         if (isnan(temp))
  97                 is_valid = FALSE;
  98
  99         if (is_valid) {
 100                 sr_analog_init(&analog, &encoding, &meaning, &spec, 1);
 101                 analog.meaning->mq = SR_MQ_TEMPERATURE;
 102                 analog.meaning->mqflags = 0;
 103                 switch (devc->packet[5] - '0') {
 104                 case 1:
 105                         analog.meaning->unit = SR_UNIT_CELSIUS;
 106                         break;
 107                 case 2:
 108                         analog.meaning->unit = SR_UNIT_FAHRENHEIT;
 109                         break;
 110                 case 3:
 111                         analog.meaning->unit = SR_UNIT_KELVIN;
 112                         break;
 113                 default:
 114                         /* We can still pass on the measurement, whatever it is. */
 115                         sr_dbg("Unknown unit 0x%.2x.", devc->packet[5]);
 116                 }
 117                 switch (devc->packet[13] - '0') {
 118                 case 0:
 119                         /* Channel T1. */
 120                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 0));
 121                         break;
 122                 case 1:
 123                         /* Channel T2. */
 124                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 1));
 125                         break;
 126                 case 2:
 127                 case 3:
 128                         /* Channel T1-T2. */
 129                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 2));
 130                         analog.meaning->mqflags |= SR_MQFLAG_RELATIVE;
 131                         break;
 132                 default:
 133                         sr_err("Unknown channel 0x%.2x.", devc->packet[13]);
 134                         is_valid = FALSE;
 135                 }
 136                 if (is_valid) {
 137                         analog.num_samples = 1;
 138                         analog.data = &temp;
 139                         packet.type = SR_DF_ANALOG;
 140                         packet.payload = &analog;
 141                         sr_session_send(sdi, &packet);
 142                         g_slist_free(analog.meaning->channels);
 143                 }
 144         }
 145
 146         /*
 147          * We count packets even if the measurement was invalid. This way
 148          * a sample limit on "Memory" data source still works: Unused
 149          * memory slots come through as "----" measurements.
 150          */
 151         sr_sw_limits_update_samples_read(&devc->limits, 1);
 152         if (sr_sw_limits_check(&devc->limits))
 153                 sr_dev_acquisition_stop(sdi);
 154 }
 155
 156 SR_PRIV void LIBUSB_CALL uni_t_ut32x_receive_transfer(struct libusb_transfer *transfer)
 157 {
 158         struct dev_context *devc;
 159         struct sr_dev_inst *sdi;
 160         int hid_payload_len, ret;
 161
 162         sdi = transfer->user_data;
 163         devc = sdi->priv;
 164         if (transfer->actual_length == 8) {
 165                 /* CH9325 encodes length in low nibble of first byte, with
 166                  * bytes 1-7 being the (padded) payload. */
 167                 hid_payload_len = transfer->buffer[0] & 0x0f;
 168                 memcpy(devc->packet + devc->packet_len, transfer->buffer + 1,
 169                                 hid_payload_len);
 170                 devc->packet_len += hid_payload_len;
 171                 if (devc->packet_len >= 2
 172                                 && devc->packet[devc->packet_len - 2] == SEP[0]
 173                                 && devc->packet[devc->packet_len - 1] == SEP[1]) {
 174                         /* Got end of packet, but do we have a complete packet? */
 175                         if (devc->packet_len == PACKET_SIZE)
 176                                 process_packet(sdi);
 177                         /* Either way, done with it. */
 178                         devc->packet_len = 0;
 179                 } else if (devc->packet_len > PACKET_SIZE) {
 180                         /* Guard against garbage from the device overrunning
 181                          * our packet buffer. */
 182                         sr_dbg("Buffer overrun!");
 183                         devc->packet_len = 0;
 184                 }
 185         }
 186
 187         /* Get the next transfer (unless we're shutting down). */
 188         if (sdi->status != SR_ST_STOPPING) {
 189                 if ((ret = libusb_submit_transfer(devc->xfer)) != 0) {
 190                         sr_dbg("Failed to resubmit transfer: %s", libusb_error_name(ret));
 191                         sdi->status = SR_ST_STOPPING;
 192                         libusb_free_transfer(devc->xfer);
 193                 }
 194         } else
 195                 libusb_free_transfer(devc->xfer);
 196
 197 }
 198
 199 SR_PRIV int uni_t_ut32x_handle_events(int fd, int revents, void *cb_data)
 200 {
 201         struct drv_context *drvc;
 202         struct dev_context *devc;
 203         struct sr_dev_driver *di;
 204         struct sr_dev_inst *sdi;
 205         struct sr_usb_dev_inst *usb;
 206         struct timeval tv;
 207         int len, ret;
 208         unsigned char cmd[2];
 209
 210         (void)fd;
 211         (void)revents;
 212
 213         if (!(sdi = cb_data))
 214                 return TRUE;
 215
 216         di = sdi->driver;
 217         drvc = di->context;
 218
 219         if (!(devc = sdi->priv))
 220                 return TRUE;
 221
 222         memset(&tv, 0, sizeof(struct timeval));
 223         libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx, &tv,
 224                         NULL);
 225
 226         if (sdi->status == SR_ST_STOPPING) {
 227                 usb_source_remove(sdi->session, drvc->sr_ctx);
 228                 std_session_send_df_end(sdi);
 229
 230                 /* Tell the device to stop sending USB packets. */
 231                 usb = sdi->conn;
 232                 cmd[0] = 0x01;
 233                 cmd[1] = CMD_STOP;
 234                 ret = libusb_bulk_transfer(usb->devhdl, EP_OUT, cmd, 2, &len, 5);
 235                 if (ret != 0 || len != 2) {
 236                         /* Warning only, doesn't matter. */
 237                         sr_dbg("Failed to send stop command: %s", libusb_error_name(ret));
 238                 }
 239
 240                 sdi->status = SR_ST_ACTIVE;
 241                 return TRUE;
 242         }
 243
 244         return TRUE;
 245 }