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Support fixed packet length frames on the FSK decoder

This commit is contained in:
Manolis Surligas 2017-04-15 02:41:47 +03:00
parent a8d0eae736
commit f1ff356193
4 changed files with 60 additions and 17 deletions
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11
grc/satellites/upsat/satnogs_upsat_fsk_frame_acquisition.xml
View File

@ -3,7 +3,7 @@
<name>UPSAT FSK Frame Acquisition</name>
<key>satnogs_upsat_fsk_frame_acquisition</key>
<import>import satnogs</import>
<make>satnogs.upsat_fsk_frame_acquisition($preamble, $sync_word, $whitening, $manchester, $check_crc, $ax_25, $whitening_mask, $whitening_seed, $whitening_order)</make>
<make>satnogs.upsat_fsk_frame_acquisition($preamble, $sync_word, $whitening, $manchester, $check_crc, $ax_25, $whitening_mask, $whitening_seed, $whitening_order, $packet_len)</make>
<param>
<name>Frame Preamble</name>
@ -87,12 +87,19 @@
<type>int</type>
</param>
<param>
<param>
<name>Whitening order</name>
<key>whitening_order</key>
<value>17</value>
<type>int</type>
</param>
<param>
<name>Packet length</name>
<key>packet_len</key>
<value>0</value>
<type>int</type>
</param>
<sink>
<name>in</name>

7
include/satnogs/upsat_fsk_frame_acquisition.h
View File

@ -68,6 +68,10 @@ namespace gr
* @param whitening_mask the polynomial of the scrambler
* @param whitening_seed the initial seed of the scrambler
* @param whitening_order the size of the scrambler's LFSR
* @param packet_len if set to 0 the decoder enters the variable
* packet length mode, where the packet length is indicated from the
* first byte after the SYNC word. Otherwise this field specifies the
* payload length in bytes.
*/
static sptr
make (const std::vector<uint8_t> &preamble,
@ -76,7 +80,8 @@ namespace gr
bool ax25_format = false,
uint32_t whitening_mask = 0x1001,
uint32_t whitening_seed = 0x1FF,
uint32_t whitening_order = 17);
uint32_t whitening_order = 17,
size_t packet_len = 0);
};
} // namespace satnogs

55
lib/upsat_fsk_frame_acquisition_impl.cc
View File

@ -42,14 +42,16 @@ namespace gr
bool check_crc, bool ax25_format,
uint32_t whitening_mask,
uint32_t whitening_seed,
uint32_t whitening_order)
uint32_t whitening_order,
size_t packet_len)
{
return gnuradio::get_initial_sptr (
new upsat_fsk_frame_acquisition_impl (preamble, sync_word, whitening,
manchester, check_crc,
ax25_format, whitening_mask,
whitening_seed,
whitening_order));
whitening_order,
packet_len));
}
/*
@ -59,7 +61,8 @@ namespace gr
const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word, bool whitening, bool manchester,
bool check_crc, bool ax25_format, uint32_t whitening_mask,
uint32_t whitening_seed, uint32_t whitening_order) :
uint32_t whitening_seed, uint32_t whitening_order,
size_t packet_len) :
gr::sync_block ("upsat_fsk_frame_acquisition",
gr::io_signature::make (1, 1, sizeof(float)),
gr::io_signature::make (0, 0, 0)),
@ -78,6 +81,7 @@ namespace gr
d_manchester (manchester),
d_check_crc (check_crc),
d_is_ax25 (ax25_format),
d_var_packet_len(packet_len == 0),
d_state (SEARCHING),
d_shifting_byte (0x0),
d_decoded_bytes (0),
@ -106,6 +110,9 @@ namespace gr
d_pdu = new uint8_t[UPSAT_MAX_FRAME_LEN];
d_ax25_tmp_buf = new uint8_t[2 * UPSAT_MAX_FRAME_LEN * 8];
d_ax25_buf = new uint8_t[2 * UPSAT_MAX_FRAME_LEN];
/* If the fixed packet length is set, store the expected frame size */
d_frame_len = packet_len;
}
/*
@ -180,7 +187,12 @@ namespace gr
{
LOG_DEBUG("Enter have payload");
d_state = HAVE_PAYLOAD;
d_decoded_bytes = 1;
if(d_var_packet_len) {
d_decoded_bytes = 1;
}
else {
d_decoded_bytes = 0;
}
d_decoded_bits = 0;
}
@ -219,7 +231,11 @@ namespace gr
uint16_t crc_calc;
size_t ax25_frame_len = 0;
ax25_decode_status_t status;
size_t payload_len;
uint8_t *payload;
const float *in = (const float *) input_items[0];
for (i = 0; i < noutput_items; i++) {
slice_and_shift (in[i]);
@ -276,7 +292,12 @@ namespace gr
if (d_shifting_byte == d_sync_word[d_decoded_bytes]) {
d_decoded_bytes++;
if (d_decoded_bytes == d_sync_word_len) {
have_frame_len ();
if(d_var_packet_len) {
have_frame_len ();
}
else{
have_payload();
}
}
}
else {
@ -307,6 +328,15 @@ namespace gr
case HAVE_PAYLOAD:
d_decoded_bits++;
if (d_decoded_bits == 8) {
if(d_var_packet_len) {
payload = d_pdu + 1;
payload_len = d_frame_len - 1;
}
else{
payload = d_pdu;
payload_len = d_frame_len;
}
d_decoded_bits = 0;
d_pdu[d_decoded_bytes] = d_shifting_byte;
d_decoded_bytes++;
@ -314,9 +344,9 @@ namespace gr
if (d_decoded_bytes == d_frame_len) {
if (d_is_ax25) {
unpack_ax25_bytes (d_frame_len - 1);
unpack_ax25_bytes (payload_len);
status = ax25_decode (d_ax25_buf, &ax25_frame_len,
d_ax25_tmp_buf, (d_frame_len - 1) * 8);
d_ax25_tmp_buf, payload_len * 8);
if (status == AX25_DEC_OK) {
/* Skip the AX.25 header */
message_port_pub (
@ -335,15 +365,14 @@ namespace gr
}
if (d_whitening) {
d_descrambler.descramble (d_pdu + 1, d_pdu + 1,
d_frame_len - 1);
d_descrambler.descramble (payload, payload, payload_len);
}
if (!d_check_crc) {
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
pmt::make_blob (payload,
payload_len - sizeof(uint16_t)));
reset_state ();
break;
}
@ -357,8 +386,8 @@ namespace gr
if (crc_calc == crc_received) {
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
pmt::make_blob (payload,
payload_len - sizeof(uint16_t)));
}
else {
LOG_WARN("Frame with wrong CRC got 0x%x calc 0x%x",

4
lib/upsat_fsk_frame_acquisition_impl.h
View File

@ -57,6 +57,7 @@ namespace gr
const bool d_manchester;
const bool d_check_crc;
const bool d_is_ax25;
const bool d_var_packet_len;
decoding_state_t d_state;
uint8_t d_shifting_byte;
size_t d_decoded_bytes;
@ -92,7 +93,8 @@ namespace gr
bool check_crc, bool ax25_format,
uint32_t whitening_mask,
uint32_t whitening_seed,
uint32_t whitening_order);
uint32_t whitening_order,
size_t packet_len);
~upsat_fsk_frame_acquisition_impl ();
// Where all the action really happens