mordae/pico-sdr
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Improve NCO flexibility

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This commit is contained in:
Jan Hamal Dvořák 2024-08-07 00:01:37 +02:00
parent 63d9a59fe6
commit b31fc626e3
1 changed files with 41 additions and 24 deletions
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65
src/main.c
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@ -43,23 +43,21 @@
#define ADC_RATE (2 * MHZ)
#define DECIMATE 4
/*
* NOTE: Must have 256 phases with 256 bytes each.
* Otherwise the DMA 1-byte write trick wouldn't work.
*/
#define LO_NUM_PHASES 256
#define LO_PHASE_BITS 8
#define LO_PHASE_WORDS (1 << (LO_PHASE_BITS - 2))
#define NCO_NUM_PHASES (1 << 8)
#define NCO_PHASE_BITS 8
#define NCO_PHASE_WORDS (1 << (NCO_PHASE_BITS - 2))
#define STEP_BASE ((UINT_MAX + 1.0) / CLK_SYS_HZ)
static uint32_t nco_step = (uint32_t)(STEP_BASE * INIT_FREQ) * 32 * LO_PHASE_WORDS;
static uint32_t nco_step = (uint32_t)(STEP_BASE * INIT_FREQ) * 32 * NCO_PHASE_WORDS;
static uint32_t nco_null = 0;
static uint32_t nco_mask = (1 << NCO_PHASE_BITS) - 1;
static uint32_t lo_phase[LO_NUM_PHASES][LO_PHASE_WORDS]
__attribute__((__aligned__(LO_NUM_PHASES * 4 * LO_PHASE_WORDS)));
static uint32_t nco_phase[NCO_NUM_PHASES][NCO_PHASE_WORDS]
__attribute__((__aligned__(NCO_NUM_PHASES * 4 * NCO_PHASE_WORDS)));
static uint32_t nco_addr = (uint32_t)lo_phase;
static_assert(sizeof(nco_phase) == 65536, "sizeof(nco_phase) == 65536");
static uint32_t *nco_addr = &nco_phase[0][0];
#define NUM_GAINS 29
static int gains[NUM_GAINS] = { 0, 9, 14, 27, 37, 77, 87, 125, 144, 157,
@ -72,6 +70,7 @@ static int frequency = INIT_FREQ;
static int dma_ch_nco1 = -1;
static int dma_ch_nco2 = -1;
static int dma_ch_nco3 = -1;
static int dma_ch_nco4 = -1;
static int dma_ch_mix = -1;
static queue_t iq_queue;
@ -133,7 +132,7 @@ static void init_lo()
pio_sm_exec_wait_blocking(PIO, SM_LO, pio_encode_set(pio_pins, 0));
}
static void lo_generate_phase(uint32_t *buf, size_t len, uint32_t step, uint32_t phase)
static void nco_generate_phase(uint32_t *buf, size_t len, uint32_t step, uint32_t phase)
{
for (size_t i = 0; i < len; i++) {
uint32_t bits = 0;
@ -152,10 +151,11 @@ static void rx_lo_init(double freq)
{
uint32_t step = STEP_BASE * freq;
for (uint32_t i = 0; i < LO_NUM_PHASES; i++)
lo_generate_phase(lo_phase[i], LO_PHASE_WORDS, step, i << 24);
for (uint32_t i = 0; i < NCO_NUM_PHASES; i++)
nco_generate_phase(nco_phase[i], NCO_PHASE_WORDS, step,
i << (__builtin_clz(NCO_NUM_PHASES) + 1));
nco_step = step * 32 * LO_PHASE_WORDS;
nco_step = step * 32 * NCO_PHASE_WORDS;
}
static void rf_rx_start()
@ -163,6 +163,7 @@ static void rf_rx_start()
dma_ch_nco1 = dma_claim_unused_channel(true);
dma_ch_nco2 = dma_claim_unused_channel(true);
dma_ch_nco3 = dma_claim_unused_channel(true);
dma_ch_nco4 = dma_claim_unused_channel(true);
dma_ch_mix = dma_claim_unused_channel(true);
dma_channel_config dma_conf;
@ -180,20 +181,31 @@ static void rf_rx_start()
/* Prepare the phase address. */
dma_conf = dma_channel_get_default_config(dma_ch_nco2);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_8);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_16);
channel_config_set_read_increment(&dma_conf, false);
channel_config_set_write_increment(&dma_conf, false);
channel_config_set_chain_to(&dma_conf, dma_ch_nco3);
dma_channel_configure(dma_ch_nco2, &dma_conf, (uint8_t *)(&nco_addr) + 1,
((uint8_t *)&dma_hw->sniff_data) + 3, 1, false);
dma_channel_configure(dma_ch_nco2, &dma_conf, (void *)(&nco_addr) + 0,
((void *)&dma_hw->sniff_data) + 2, 1, false);
/* Trigger LO using the address. */
/* Copy it to the DMA. */
dma_conf = dma_channel_get_default_config(dma_ch_nco3);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_32);
channel_config_set_read_increment(&dma_conf, false);
channel_config_set_write_increment(&dma_conf, false);
dma_channel_configure(dma_ch_nco3, &dma_conf, &dma_hw->ch[dma_ch_mix].al3_read_addr_trig,
&nco_addr, 1, false);
channel_config_set_chain_to(&dma_conf, dma_ch_nco4);
dma_channel_configure(dma_ch_nco3, &dma_conf, &dma_hw->ch[dma_ch_mix].read_addr, &nco_addr,
1, false);
/* Trigger LO by clearing the bottom bits. */
dma_conf = dma_channel_get_default_config(dma_ch_nco4);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_32);
channel_config_set_read_increment(&dma_conf, false);
channel_config_set_write_increment(&dma_conf, false);
dma_channel_configure(dma_ch_nco4, &dma_conf,
(void *)&dma_hw->ch[dma_ch_mix].al3_read_addr_trig +
REG_ALIAS_CLR_BITS,
&nco_mask, 1, false);
/* Drive the LO capacitor. */
dma_conf = dma_channel_get_default_config(dma_ch_mix);
@ -202,8 +214,8 @@ static void rf_rx_start()
channel_config_set_write_increment(&dma_conf, false);
channel_config_set_dreq(&dma_conf, pio_get_dreq(PIO, SM_LO, GPIO_OUT));
channel_config_set_chain_to(&dma_conf, dma_ch_nco1);
dma_channel_configure(dma_ch_mix, &dma_conf, &PIO->txf[SM_LO], lo_phase, LO_PHASE_WORDS,
false);
dma_channel_configure(dma_ch_mix, &dma_conf, &PIO->txf[SM_LO], &nco_phase[0][0],
NCO_PHASE_WORDS, false);
init_lo();
@ -221,26 +233,31 @@ static void rf_rx_stop(void)
dma_channel_clear_chain_to(dma_ch_nco1);
dma_channel_clear_chain_to(dma_ch_nco2);
dma_channel_clear_chain_to(dma_ch_nco3);
dma_channel_clear_chain_to(dma_ch_nco4);
dma_channel_clear_chain_to(dma_ch_mix);
dma_channel_abort(dma_ch_nco1);
dma_channel_abort(dma_ch_nco2);
dma_channel_abort(dma_ch_nco3);
dma_channel_abort(dma_ch_nco4);
dma_channel_abort(dma_ch_mix);
dma_channel_cleanup(dma_ch_nco1);
dma_channel_cleanup(dma_ch_nco2);
dma_channel_cleanup(dma_ch_nco3);
dma_channel_cleanup(dma_ch_nco4);
dma_channel_cleanup(dma_ch_mix);
dma_channel_unclaim(dma_ch_nco1);
dma_channel_unclaim(dma_ch_nco2);
dma_channel_unclaim(dma_ch_nco3);
dma_channel_unclaim(dma_ch_nco4);
dma_channel_unclaim(dma_ch_mix);
dma_ch_nco1 = -1;
dma_ch_nco2 = -1;
dma_ch_nco3 = -1;
dma_ch_nco4 = -1;
dma_ch_mix = -1;
}