--- /dev/null
+/* DSC sensor
+ *
+ *
+ * Decode DSC security contact messages
+ *
+ * Copyright (C) 2015 Tommy Vestermark
+ * Copyright (C) 2015 Robert C. Terzi
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * DSC - Digital Security Controls 433 Mhz Wireless Security Contacts
+ * doors, windows, smoke, CO2, water,
+ *
+ * Protcol Description available in this FCC Report for FCC ID F5300NB912
+ * https://apps.fcc.gov/eas/GetApplicationAttachment.html?id=100988
+ *
+ * General Packet Description
+ * - Packets are 26.5 mS long
+ * - Packets start with 2.5 mS of constant modulation for most sensors
+ * Smoke/CO2/Fire sensors start with 5.6 mS of constant modulation
+ * - The length of a bit is 500 uS, broken into two 250 uS segments.
+ * A logic 0 is 500 uS (2 x 250 uS) of no signal.
+ * A logic 1 is 250 uS of no signal followed by 250 uS of signal/keying
+ * - Then there are 4 sync logic 1 bits.
+ * - There is a sync/start 1 bit in between every 8 bits.
+ * - A zero byte would be 8 x 500 uS of no signal (plus the 250 uS of
+ * silence for the first half of the next 1 bit) for a maximum total
+ * of 4,250 uS (4.25 mS) of silence.
+ * - The last byte is a CRC with nothing after it, no stop/sync bit, so
+ * if there was a CRC byte of 0, the packet would wind up being short
+ * by 4 mS and up to 8 bits (48 bits total).
+ *
+ * There are 48 bits in the packet including the leading 4 sync 1 bits.
+ * This makes the packet 48 x 500 uS bits long plus the 2.5 mS preamble
+ * for a total packet length of 26.5 ms. (smoke will be 3.1 ms longer)
+ *
+ * Packet Decoding
+ * Check intermessage start / sync bits, every 8 bits
+ * Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
+ * vvvv v v v v
+ * SSSSdddd ddddSddd dddddSdd ddddddSd dddddddS cccccccc Sync,data,crc
+ * 01234567 89012345 67890123 45678901 23456789 01234567 Received Bit No.
+ * 84218421 84218421 84218421 84218421 84218421 84218421 Received Bit Pos.
+ *
+ # SSSS S S S S Synb bit positions
+ * ssss ssss ttt teeee ee eeeeee e eeeeeee cccccccc type
+ * tttt tttt yyy y1111 22 223333 4 4445555 rrrrrrrr
+ *
+ * Bits: 0,1,2,3,12,21,30,39 should == 1
+ *
+ * Status (st) = 8 bits, open, closed, tamper, repeat
+ * Type (ty) = 4 bits, Sensor type, really first nybble of ESN
+ * ESN (e1-5) = 20 bits, Electronic Serial Number: Sensor ID.
+ * CRC (cr) = 8 bits, CRC, type/polynom to be determined
+ *
+ * The ESN in practice is 24 bits, The type + remaining 5 nybbles,
+ *
+ * The CRC is 8 bit, "little endian", Polynomial 0xf5, Inital value 0x3d
+ *
+ * CRC algorithm found with CRC reveng (reveng.sourceforge.net)
+ *
+ * CRC Model Parameters:
+ * width=8 poly=0xf5 init=0x3d refin=true refout=true xorout=0x00 check=0xfd name=(none)
+ *
+ */
+
+#include "rtl_433.h"
+#include "util.h"
+
+#define DSC_CT_MSGLEN 5
+#define DSC_CT_CRC_POLY 0xf5
+#define DSC_CT_CRC_INIT 0x3d
+
+
+static int DSC_callback(bitbuffer_t *bitbuffer) {
+ bitrow_t *bb = bitbuffer->bb;
+ int valid_cnt = 0;
+ char time_str[LOCAL_TIME_BUFLEN];
+
+ if (debug_output > 1) {
+ fprintf(stderr,"Possible DSC Contact: ");
+ bitbuffer_print(bitbuffer);
+ }
+
+ for (int row = 0; row < bitbuffer->num_rows; row++) {
+ if (debug_output > 1 && bitbuffer->bits_per_row[row] > 0 ) {
+ fprintf(stderr,"row %d bit count %d\n", row,
+ bitbuffer->bits_per_row[row]);
+ }
+
+ // Number of bits in the packet should be 48 but due to the
+ // encoding of trailing zeros is a guess based on reset_limit /
+ // long_limit (bit period). With current values up to 10 zero
+ // bits could be added, so it is normal to get a 58 bit packet.
+ //
+ // If the limits are changed for some reason, the max number of bits
+ // will need to be changed as there may be more zero bit padding
+ if (bitbuffer->bits_per_row[row] < 48 ||
+ bitbuffer->bits_per_row[row] > 70) { // should be 48 at most
+ if (debug_output > 1 && bitbuffer->bits_per_row[row] > 0) {
+ fprintf(stderr,"DSC row %d invalid bit count %d\n",
+ row, bitbuffer->bits_per_row[row]);
+ }
+ continue;
+ }
+
+ // Validate Sync/Start bits == 1 and are in the right position
+ if (!((bb[row][0] & 0xF0) && // First 4 bits are start/sync bits
+ (bb[row][1] & 0x08) && // Another sync/start bit between
+ (bb[row][2] & 0x04) && // every 8 data bits
+ (bb[row][3] & 0x02) &&
+ (bb[row][4] & 0x01))) {
+ if (debug_output > 1) {
+ fprintf(stderr,
+ "DSC Invalid start/sync bits %02x %02x %02x %02x %02x\n",
+ bb[row][0] & 0xF0,
+ bb[row][1] & 0x08,
+ bb[row][2] & 0x04,
+ bb[row][3] & 0x02,
+ bb[row][4] & 0x01);
+ }
+ continue;
+ }
+
+ uint8_t bytes[5];
+ uint8_t status,crc;
+ uint32_t esn;
+ uint8_t crcc1, crcc2, crcc3, crcc4, crcc5, crcc6, crcc7, crcc8;
+
+ bytes[0] = ((bb[row][0] & 0x0F) << 4) | ((bb[row][1] & 0xF0) >> 4);
+ bytes[1] = ((bb[row][1] & 0x07) << 5) | ((bb[row][2] & 0xF8) >> 3);
+ bytes[2] = ((bb[row][2] & 0x03) << 6) | ((bb[row][3] & 0xFC) >> 2);
+ bytes[3] = ((bb[row][3] & 0x01) << 7) | ((bb[row][4] & 0xFE) >> 1);
+ bytes[4] = ((bb[row][5]));
+
+ // XXX change to debug_output
+ if (debug_output)
+ fprintf(stdout, "DSC Contact Raw Data: %02X %02X %02X %02X %02X\n",
+ bytes[0], bytes[1], bytes[2], bytes[3], bytes[4]);
+
+ status = bytes[0];
+ esn = (bytes[1] << 16) | (bytes[2] << 8) | bytes[3];
+ crc = bytes[4];
+
+ local_time_str(0, time_str);
+
+ if (crc8le(bytes, DSC_CT_MSGLEN, DSC_CT_CRC_POLY, DSC_CT_CRC_INIT) == 0) {
+ printf("%s DSC Contact ESN: %06X, Status: %02X, CRC: %02X\n",
+ time_str, esn, status, crc);
+
+ valid_cnt++; // Have a valid packet.
+ } else if (debug_output) {
+ fprintf(stderr,"%s DSC Contact bad CRC: %06X, Status: %02X, CRC: %02X\n",
+ time_str, esn, status, crc);
+ }
+ }
+
+ if (valid_cnt) {
+ return 1;
+ }
+
+ return 0;
+}
+
+
+r_device DSC = {
+ .name = "DSC Security Contact",
+ .modulation = OOK_PULSE_PCM_RZ,
+ .short_limit = 250, // Pulse length, 250 µs
+ .long_limit = 500, // Bit period, 500 µs
+ .reset_limit = 5000, // Max gap,
+ .json_callback = &DSC_callback,
+ .disabled = 1,
+ .demod_arg = 0,
+};
+
+
+
projects / rtl-433.git / blobdiff