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Add Wireless M-Bus, Mode T Downlink (#2366)

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This commit is contained in:
Christian W. Zuckschwerdt
2023-02-04 19:41:29 +01:00
committed by GitHub
parent 1eb23fdb73
commit 96d2c600b7
1 changed files with 40 additions and 7 deletions
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47
src/devices/m_bus.c
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@@ -63,6 +63,9 @@ static int m_bus_decode_3of6_buffer(uint8_t const *bits, unsigned bit_offset, ui
for (unsigned n=0; n<num_bytes; ++n) {
uint8_t nibble_h = m_bus_decode_3of6(bitrow_get_byte(bits, n*12+bit_offset) >> 2);
uint8_t nibble_l = m_bus_decode_3of6(bitrow_get_byte(bits, n*12+bit_offset+6) >> 2);
if (nibble_h > 0xf || nibble_l > 0xf) {
return -1;
}
output[n] = (nibble_h << 4) | nibble_l;
}
return 0;
@@ -984,7 +987,8 @@ static int m_bus_mode_c_t_callback(r_device *decoder, bitbuffer_t *bitbuffer)
data_in.length = (bitbuffer->bits_per_row[0]-bit_offset)/8;
bitbuffer_extract_bytes(bitbuffer, 0, bit_offset, data_in.data, data_in.length*8);
// Decode
if (!m_bus_decode_format_a(decoder, &data_in, &data_out, &block1)) return 0;
if (!m_bus_decode_format_a(decoder, &data_in, &data_out, &block1))
return DECODE_FAIL_SANITY;
} // Format A
// Format B
else if (next_byte == 0x3D) {
@@ -993,8 +997,9 @@ static int m_bus_mode_c_t_callback(r_device *decoder, bitbuffer_t *bitbuffer)
data_in.length = (bitbuffer->bits_per_row[0]-bit_offset)/8;
bitbuffer_extract_bytes(bitbuffer, 0, bit_offset, data_in.data, data_in.length*8);
// Decode
if (!m_bus_decode_format_b(decoder, &data_in, &data_out, &block1)) return 0;
} // Format B
if (!m_bus_decode_format_b(decoder, &data_in, &data_out, &block1))
return DECODE_FAIL_SANITY;
} // Format B
// Unknown Format
else {
decoder_logf_bitbuffer(decoder, 1, __func__, bitbuffer, "M-Bus: Mode C, Unknown format: 0x%X", next_byte);
@@ -1014,10 +1019,13 @@ static int m_bus_mode_c_t_callback(r_device *decoder, bitbuffer_t *bitbuffer)
decoder_logf(decoder, 1, __func__, "MBus telegram length: %u", data_in.length);
if (m_bus_decode_3of6_buffer(bitbuffer->bb[0], bit_offset, data_in.data, data_in.length) < 0) {
decoder_log(decoder, 1, __func__, "M-Bus: Decoding error");
return 0;
return DECODE_FAIL_SANITY;
}
// Decode
if (!m_bus_decode_format_a(decoder, &data_in, &data_out, &block1)) return 0;
if (!m_bus_decode_format_a(decoder, &data_in, &data_out, &block1)) {
decoder_log_bitrow(decoder, 1, __func__, data_in.data, data_in.length, "MBus telegram unknown format");
return DECODE_FAIL_SANITY;
}
} // Mode T
m_bus_output_data(decoder, bitbuffer, &data_out, &block1, mode);
@@ -1119,6 +1127,7 @@ Wireless M-Bus, Mode S.
static int m_bus_mode_s_callback(r_device *decoder, bitbuffer_t *bitbuffer)
{
static const uint8_t PREAMBLE_S[] = {0x54, 0x76, 0x96}; // Mode S Preamble
static const uint8_t PREAMBLE_T_DN[] = {0xaa, 0xab, 0x32}; // Mode T Downlink Preamble
bitbuffer_t packet_bits = {0};
m_bus_data_t data_in = {0}; // Data from Physical layer decoded to bytes
m_bus_data_t data_out = {0}; // Data from Data Link layer
@@ -1129,9 +1138,22 @@ static int m_bus_mode_s_callback(r_device *decoder, bitbuffer_t *bitbuffer)
return DECODE_ABORT_LENGTH;
}
// Find a Mode T-downlink data package
unsigned offset = bitbuffer_search(bitbuffer, 0, 0, PREAMBLE_T_DN, sizeof(PREAMBLE_T_DN) * 8);
offset += sizeof(PREAMBLE_T_DN) * 8;
if (offset < bitbuffer->bits_per_row[0]) { // Did find a big enough package
bitbuffer_invert(bitbuffer);
decoder_logf_bitbuffer(decoder, 1, __func__, bitbuffer, "M-Bus: Mode T Downlink");
return DECODE_ABORT_EARLY;
}
// Find a Mode S data package
unsigned bit_offset = bitbuffer_search(bitbuffer, 0, 0, PREAMBLE_S, sizeof(PREAMBLE_S)*8);
bitbuffer_manchester_decode(bitbuffer, 0, bit_offset+sizeof(PREAMBLE_S)*8, &packet_bits, 800);
bit_offset += sizeof(PREAMBLE_S) * 8;
if (bit_offset >= bitbuffer->bits_per_row[0]) { // Did not find a big enough package
return DECODE_ABORT_EARLY;
}
bitbuffer_manchester_decode(bitbuffer, 0, bit_offset, &packet_bits, 800);
data_in.length = (bitbuffer->bits_per_row[0]);
bitbuffer_extract_bytes(&packet_bits, 0, 0, data_in.data, data_in.length);
@@ -1188,7 +1210,7 @@ static char *output_fields[] = {
};
// Mode C1, C2 (Meter TX), T1, T2 (Meter TX),
// Frequency 868.95 MHz, Bitrate 100 kbps, Modulation NRZ FSK
// Frequency 868.95 MHz, Bitrate 100 kbps (uplink), Modulation NRZ FSK
r_device const m_bus_mode_c_t = {
.name = "Wireless M-Bus, Mode C&T, 100kbps (-f 868.95M -s 1200k)", // Minimum samplerate = 1.2 MHz (12 samples of 100kb/s)
.modulation = FSK_PULSE_PCM,
@@ -1199,6 +1221,17 @@ r_device const m_bus_mode_c_t = {
.fields = output_fields,
};
// Mode T communication in downlink direction at 32.768 kbps
r_device const m_bus_mode_c_t_downlink = {
.name = "Wireless M-Bus, Mode T, 32.768kbps (-f 868.3M -s 1000k)", // Minimum samplerate = 1 MHz (15 samples of 32kb/s manchester coded)
.modulation = FSK_PULSE_PCM,
.short_width = (1000.0 / 32.768), // ~31 us per bit
.long_width = (1000.0 / 32.768),
.reset_limit = ((1000.0 / 32.768) * 9), // 9 bit periods
.decode_fn = &m_bus_mode_c_t_callback,
.fields = output_fields,
};
// Mode S1, S1-m, S2, T2 (Meter RX), (Meter RX not so interesting)
// Frequency 868.3 MHz, Bitrate 32.768 kbps, Modulation Manchester FSK
r_device const m_bus_mode_s = {