| 1 | function [fft_load, fft_lts_load, samp_skip_mode] = rx_fft_ctrl_fsm(lts_sync, fft_load_done, pkt_done) |
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| 2 | |
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| 3 | persistent fsm_state, fsm_state=xl_state(0, {xlUnsigned, 3, 0}); |
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| 4 | |
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| 5 | %Inputs: |
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| 6 | % lts_sync: Successful correlation of second LTS (must be 1 cycle) |
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| 7 | % fft_load_done: Last FFT input sample loaded |
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| 8 | % pkt_done: Resets state (last FFT is performed, pkt Rx ends early, etc.) |
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| 9 | |
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| 10 | %Outputs: |
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| 11 | % fft_load: Start FFT load operation |
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| 12 | % samp_skip_mode: Selection of number of samples to skip post FFT load |
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| 13 | % 0: Skip 0 samples (first LTS) |
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| 14 | % 1: Skip CP_LEN samples (second LTS and all DATA symbols) |
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| 15 | |
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| 16 | %States: |
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| 17 | % ST_LTS_WAIT: Waiting for LTS sync (this is the idle/reset state) |
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| 18 | % ST_LTS_LOAD1: Load first LTS into FFT |
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| 19 | % ST_LTS_LOAD2: Load second LTS into FFT |
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| 20 | % ST_DATA_LOAD: Load DATA symbols into FFT |
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| 21 | % ST_DATA_DONE: Finished loading DATA symbols (returns to LTS_WAIT) |
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| 22 | |
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| 23 | ST_LTS_WAIT = 0; |
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| 24 | ST_LTS_LOAD1 = 1; |
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| 25 | ST_LTS_LOAD2 = 2; |
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| 26 | ST_DATA_LOAD = 3; |
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| 27 | ST_DATA_DONE = 4; |
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| 28 | |
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| 29 | switch double(fsm_state) |
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| 30 | |
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| 31 | case ST_LTS_WAIT |
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| 32 | fft_load = 0; |
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| 33 | samp_skip_mode = 0; |
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| 34 | fft_lts_load = 0; |
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| 35 | |
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| 36 | if( (pkt_done==1) ) |
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| 37 | fsm_state = ST_LTS_WAIT; |
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| 38 | elseif( (lts_sync==1) ) |
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| 39 | fsm_state = ST_LTS_LOAD1; |
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| 40 | else |
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| 41 | fsm_state = ST_LTS_WAIT; |
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| 42 | end |
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| 43 | |
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| 44 | case ST_LTS_LOAD1 |
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| 45 | fft_load = 0;%1; |
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| 46 | fft_lts_load = 1; |
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| 47 | samp_skip_mode = 0; |
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| 48 | |
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| 49 | if( (pkt_done==1) ) |
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| 50 | fsm_state = ST_LTS_WAIT; |
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| 51 | elseif( (fft_load_done==1) ) |
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| 52 | fsm_state = ST_LTS_LOAD2; |
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| 53 | else |
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| 54 | fsm_state = ST_LTS_LOAD1; |
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| 55 | end |
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| 56 | |
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| 57 | case ST_LTS_LOAD2 |
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| 58 | fft_load = 0;%1; |
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| 59 | fft_lts_load = 1; |
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| 60 | samp_skip_mode = 1; |
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| 61 | |
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| 62 | if( (pkt_done==1) ) |
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| 63 | fsm_state = ST_LTS_WAIT; |
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| 64 | elseif( (fft_load_done==1) ) |
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| 65 | fsm_state = ST_DATA_LOAD; |
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| 66 | else |
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| 67 | fsm_state = ST_LTS_LOAD2; |
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| 68 | end |
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| 69 | |
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| 70 | case ST_DATA_LOAD |
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| 71 | fft_load = 1; |
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| 72 | fft_lts_load = 0; |
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| 73 | samp_skip_mode = 1; |
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| 74 | |
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| 75 | if( (pkt_done==1) ) |
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| 76 | fsm_state = ST_DATA_DONE; |
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| 77 | else |
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| 78 | fsm_state = ST_DATA_LOAD; |
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| 79 | end |
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| 80 | |
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| 81 | case ST_DATA_DONE |
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| 82 | fft_load = 0; |
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| 83 | fft_lts_load = 0; |
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| 84 | samp_skip_mode = 0; |
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| 85 | fsm_state = ST_LTS_WAIT; |
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| 86 | |
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| 87 | otherwise |
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| 88 | fft_load = 0; |
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| 89 | fft_lts_load = 0; |
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| 90 | samp_skip_mode = 0; |
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| 91 | fsm_state = ST_LTS_WAIT; |
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| 92 | |
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| 93 | end %end switch |
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| 94 | |
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| 95 | end %end function |
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| 96 | |
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