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From: | Vanhoy, Garrett M - (gvanhoy) |
Subject: | [Discuss-gnuradio] Liquid DSP Flexframe and GNU Radio |
Date: | Tue, 26 Jul 2016 01:13:31 +0000 |
Hello,
I have sent this to the list once before, but I did not see it show up on the index so I am assuming it did not work after waiting some time.
I am attempting to embed the
liquid DSP flexframe protocol in a custom GNU Radio block. I am doing this by extending the out-of-tree module that
Tom Rondeau recently worked on. I am writing a block that embeds the flexframegen and another that embeds a flexframesync. Since these blocks tend to produce a varying amount of symbols
depending on the coding scheme or modulation, I wrote it as a general block. You can see the current version of the code
at my own fork.
I am currently having trouble with the generator and occasionally the sync block as well. However, for the generator, I am getting a return code -11 (I assume a seg fault) when I attempt to copy a generated frame to the out buffer and run this in GNURadioCompanion. This often happens after attempting to copy ~16000 gr_complex items to the outbuffer. Is there a problems with that amount? Here is my work function code:
unsigned int buf_len = 1000; unsigned int payload_len = 4096; unsigned char header[14]; // Liquid hardcodes this as the length for the header unsigned char payload[4096]; unsigned char *in = (unsigned char *) input_items[0]; unsigned char *inbuf = in; gr_complex *out = (gr_complex *) output_items[0]; gr_complex *outbuf = (gr_complex *) malloc(buf_len*sizeof(gr_complex)); gr_complex *front = out; int byte_count = 0; unsigned char frame_count; unsigned int total_items = 0; int frame_complete = 0; // Make header for(int i = 1; i < 14; i++) header[i] = i; while(byte_count < ((int) ninput_items[0]) - payload_len) { header[0] = frame_count; frame_count > 255 ? frame_count = 0 : frame_count++; memcpy(payload, inbuf, payload_len); inbuf += payload_len; byte_count += payload_len; // Assemble the frame while (!flexframegen_is_assembled(d_fg)) { flexframegen_assemble(d_fg, header, payload, payload_len); } // Make the frame in blocks frame_complete = 0; while (!frame_complete){ frame_complete = flexframegen_write_samples(d_fg, outbuf, buf_len); memcpy(front, outbuf, buf_len*sizeof(gr_complex)); front += buf_len; total_items += buf_len; } // Get frame length } free(outbuf); consume_each (total_items); // Tell runtime system how many output items we produced. return total_items; }
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