Small tweaks
This commit is contained in:
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053458abfd
commit
ad2a255900
2 changed files with 62 additions and 53 deletions
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@ -37,7 +37,7 @@ blocks:
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id: variable
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parameters:
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comment: ''
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value: '94_600_000'
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value: '88_200_000'
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states:
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bus_sink: false
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bus_source: false
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@ -49,7 +49,7 @@ blocks:
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id: variable
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parameters:
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comment: ''
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value: '192_000'
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value: '200_000'
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states:
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bus_sink: false
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bus_source: false
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@ -78,7 +78,7 @@ blocks:
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parameters:
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affinity: ''
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alias: ''
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audio_decimation: '4'
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audio_decimation: '8'
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comment: ''
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deemph_tau: 75e-6
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maxoutbuf: '0'
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@ -100,7 +100,7 @@ blocks:
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device_name: ''
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num_inputs: '2'
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ok_to_block: 'True'
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samp_rate: samp_rate // 4
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samp_rate: samp_rate // 8
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states:
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bus_sink: false
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bus_source: false
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@ -150,15 +150,15 @@ blocks:
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alias: ''
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beta: '6.76'
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comment: ''
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cutoff_freq: samp_rate / 8
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decim: '4'
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cutoff_freq: samp_rate / 16
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decim: '8'
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gain: '1'
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interp: '1'
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maxoutbuf: '0'
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minoutbuf: '0'
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samp_rate: samp_rate
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type: fir_filter_fff
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width: samp_rate / 8
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width: samp_rate / 16
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win: window.WIN_HAMMING
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states:
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bus_sink: false
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@ -677,7 +677,7 @@ blocks:
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name: '"FM Demodulation"'
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nconnections: '1'
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size: '512'
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srate: samp_rate // (2 ** 3)
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srate: samp_rate // 8
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stemplot: 'False'
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style1: '1'
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style10: '1'
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@ -856,4 +856,4 @@ connections:
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metadata:
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file_format: 1
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grc_version: 3.10.9.2
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grc_version: 3.10.11.0
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97
src/main.c
97
src/main.c
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@ -53,27 +53,28 @@ static uint32_t lo_sin[LO_WORDS] __attribute__((__aligned__(1 << LO_BITS_DEPTH))
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#define INIT_SAMPLE_RATE 100000
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#define INIT_FREQ 94600000
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#define INIT_GAIN 127
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#define NUM_GAINS 29
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static int gains[NUM_GAINS] = { 0, 9, 14, 27, 37, 77, 87, 125, 144, 157,
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166, 197, 207, 229, 254, 280, 297, 328, 338, 364,
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372, 386, 402, 421, 434, 439, 445, 480, 496 };
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#define BASE_GAIN (1 << 15)
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#define ATTN_BITS 8
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static int sample_rate = INIT_SAMPLE_RATE;
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static int max_amplitude = CLK_SYS_HZ / INIT_SAMPLE_RATE / 2;
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static int gain = INIT_GAIN;
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static int gain = BASE_GAIN / (CLK_SYS_HZ / INIT_SAMPLE_RATE / 2);
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static int frequency = INIT_FREQ;
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static queue_t iq_queue;
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static uint8_t iq_queue_buffer[IQ_QUEUE_LEN][IQ_BLOCK_LEN];
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static size_t iq_queue_pos = 0;
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static uint32_t rnd = 0;
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static uint32_t xorshift_seed;
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inline static __unused uint32_t rnd_next()
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static inline __unused uint32_t xorshift(void)
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{
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rnd = rnd * 0x41c64e6d + 12345;
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return rnd;
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uint32_t x = xorshift_seed;
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x ^= x << 13;
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x ^= x >> 17;
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x ^= x << 5;
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xorshift_seed = x;
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return x;
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}
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static void dma_channel_clear_chain_to(int ch)
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@ -187,6 +188,7 @@ static const uint32_t samp_insn = 16;
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static void init_adder()
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{
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const uint16_t insn[] = {
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/* y has weight of 2, x has weight of 1 */
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pio_encode_out(pio_pc, 4), // 0000 +0
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pio_encode_jmp_x_dec(0), // 0001 +1
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pio_encode_jmp_x_dec(0), // 0010 +1
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@ -428,6 +430,11 @@ static void rf_rx_stop(void)
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dma_ch_samp_sin = -1;
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}
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inline static void led_set(bool on)
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{
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gpio_put(PICO_DEFAULT_LED_PIN, on);
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}
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inline static uint32_t pio_sm_get_blocking_unsafe(pio_hw_t *pio, int sm)
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{
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while (pio->fstat & (1u << (PIO_FSTAT_RXEMPTY_LSB + sm)))
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@ -438,12 +445,18 @@ inline static uint32_t pio_sm_get_blocking_unsafe(pio_hw_t *pio, int sm)
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inline static int nextI()
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{
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static int prevI = 0;
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static int prevI2, prevI1, prevI;
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int sI = 0;
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sI -= 2 * pio_sm_get_blocking_unsafe(PIO, SM_COS);
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sI -= pio_sm_get_blocking_unsafe(PIO, SM_COS);
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int sI2 = pio_sm_get_blocking_unsafe(PIO, SM_COS);
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int I2 = sI2 - prevI2;
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prevI2 = sI2;
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int sI1 = pio_sm_get_blocking_unsafe(PIO, SM_COS);
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int I1 = sI1 - prevI1;
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prevI1 = sI1;
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int sI = I2 + I2 + I1;
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int I = sI - prevI;
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prevI = sI;
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@ -452,12 +465,18 @@ inline static int nextI()
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inline static int nextQ()
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{
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static int prevQ = 0;
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static int prevQ2, prevQ1, prevQ;
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int sQ = 0;
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sQ -= 2 * pio_sm_get_blocking_unsafe(PIO, SM_SIN);
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sQ -= pio_sm_get_blocking_unsafe(PIO, SM_SIN);
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int sQ2 = pio_sm_get_blocking_unsafe(PIO, SM_SIN);
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int Q2 = sQ2 - prevQ2;
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prevQ2 = sQ2;
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int sQ1 = pio_sm_get_blocking_unsafe(PIO, SM_SIN);
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int Q1 = sQ1 - prevQ1;
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prevQ1 = sQ1;
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int sQ = Q2 + Q2 + Q1;
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int Q = sQ - prevQ;
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prevQ = sQ;
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@ -492,28 +511,21 @@ static void rf_rx(void)
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Q -= nextI();
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I *= gain;
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I /= max_amplitude;
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I >>= ATTN_BITS;
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if (I > 127)
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I = 127;
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else if (I < -128)
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I = -128;
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*blockptr++ = (uint8_t)I + 128;
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*blockptr++ = I + 128;
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Q *= gain;
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Q /= max_amplitude;
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Q >>= ATTN_BITS;
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if (Q > 127)
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Q = 127;
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else if (Q < -128)
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Q = -128;
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*blockptr++ = (uint8_t)Q + 128;
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*blockptr++ = Q + 128;
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}
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if (queue_try_add(&iq_queue, &block)) {
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iq_queue_pos = (iq_queue_pos + 1) & (IQ_QUEUE_LEN - 1);
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iq_queue_pos = (iq_queue_pos + 1) % IQ_QUEUE_LEN;
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led_set(0);
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} else {
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led_set(1);
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}
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}
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}
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@ -527,16 +539,9 @@ static void run_command(uint8_t cmd, uint32_t arg)
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} else if (0x02 == cmd) {
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/* Set the rate at which IQ sample pairs are sent */
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sample_rate = arg;
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max_amplitude = CLK_SYS_HZ / sample_rate / 2;
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gain = BASE_GAIN / (CLK_SYS_HZ / sample_rate / 2);
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dma_timer_set_fraction(dma_t_samp, 1, CLK_SYS_HZ / (sample_rate * DECIMATE));
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rx_lo_init(frequency + sample_rate, true);
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} else if (0x04 == cmd) {
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/* Set the tuner gain level */
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gain = INIT_GAIN * pow(10.0, arg / 200.0);
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} else if (0x0d == cmd) {
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/* Set tuner gain by the tuner's gain index */
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if (arg <= NUM_GAINS)
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gain = INIT_GAIN * pow(10.0, gains[arg] / 200.0);
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}
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}
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@ -587,7 +592,7 @@ static void do_rx()
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fwrite(block, IQ_BLOCK_LEN, 1, stdout);
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fflush(stdout);
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} else {
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int wait = rnd_next() & 0x1fff;
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int wait = xorshift() >> (32 - 15);
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for (int i = 0; i < wait; i++)
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asm volatile("nop");
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@ -615,6 +620,10 @@ int main()
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gpio_set_dir(PSU_PIN, GPIO_OUT);
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gpio_put(PSU_PIN, 1);
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gpio_init(PICO_DEFAULT_LED_PIN);
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gpio_set_dir(PICO_DEFAULT_LED_PIN, GPIO_OUT);
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gpio_put(PICO_DEFAULT_LED_PIN, 0);
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/* Prioritize DMA over CPU. */
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bus_ctrl_hw->priority |= BUSCTRL_BUS_PRIORITY_DMA_W_BITS | BUSCTRL_BUS_PRIORITY_DMA_R_BITS;
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@ -633,7 +642,7 @@ int main()
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if (check_command() > 0) {
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static const uint32_t header[3] = { __builtin_bswap32(0x52544c30),
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__builtin_bswap32(5),
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__builtin_bswap32(NUM_GAINS) };
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__builtin_bswap32(29) };
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fwrite(header, sizeof header, 1, stdout);
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fflush(stdout);
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