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Add sweep, noise and faster LO generator

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Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>
This commit is contained in:
Jan Hamal Dvořák 2024-01-28 13:14:30 +01:00
parent 549b80e20e
commit 5df6824b3a
1 changed files with 84 additions and 23 deletions
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107
src/main.c
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@ -263,39 +263,27 @@ static float lo_freq_init(float req_freq)
float freq = roundf(req_freq / step_hz) * step_hz;
unsigned step = (float)UINT_MAX / (float)CLK_SYS_HZ * freq;
unsigned sin_acc = 0;
unsigned cos_acc = UINT_MAX / 4;
unsigned sin_err = 0;
unsigned cos_err = 0;
int prev_sin_bit = 0;
int prev_cos_bit = 1;
interp0->ctrl[0] = (31 << SIO_INTERP0_CTRL_LANE0_MASK_MSB_LSB) |
(0 << SIO_INTERP0_CTRL_LANE0_MASK_LSB_LSB) |
(0 << SIO_INTERP0_CTRL_LANE0_SHIFT_LSB);
interp0->ctrl[1] = interp0->ctrl[0];
interp0->base[0] = step;
interp0->base[1] = step;
interp0->accum[1] = UINT_MAX / 4;
for (int i = 0; i < LO_WORDS; i++) {
unsigned bsin = 0, bcos = 0;
for (int j = 0; j < 32; j++) {
int sin_bit = (sin_acc + sin_err) >> 31;
int sin_bit = interp0->peek[0] >> 31;
bsin |= sin_bit;
bsin <<= 1;
int cos_bit = (cos_acc + cos_err) >> 31;
int cos_bit = interp0->pop[1] >> 31;
bcos |= cos_bit;
bcos <<= 1;
if (prev_sin_bit != sin_bit) {
sin_err = (sin_acc + sin_err) & 0x7fffffff;
}
if (prev_cos_bit != cos_bit) {
cos_err = (cos_acc + cos_err) & 0x7fffffff;
}
prev_sin_bit = sin_bit;
prev_cos_bit = cos_bit;
sin_acc += step;
cos_acc += step;
}
lo_sin[i] = bsin;
@ -693,7 +681,7 @@ static void command(const char *cmd)
{
static char tmp[83];
int n, x;
float f;
float f, g;
if (1 == sscanf(cmd, " help %[\a]", tmp)) {
puts("help - this help");
@ -701,6 +689,8 @@ static void command(const char *cmd)
puts("bias I O - output negated I to O");
puts("rx N FREQ - receive on pin N");
puts("tx N FREQ - transmit on pin N");
puts("sweep N F G MS - sweep from F to G with MS at step");
puts("noise N - transmit random noise");
return;
}
@ -802,6 +792,77 @@ static void command(const char *cmd)
return;
}
if (5 == sscanf(cmd, " sweep %i %f %f %i %[\a]", &n, &f, &g, &x, tmp)) {
dma_channel_abort(tx_dma);
if (!f || !g) {
gpio_init(n);
puts("stopped");
return;
}
send_init(n);
const float step_hz = (float)CLK_SYS_HZ / (LO_WORDS * 32);
const float start = roundf(f / step_hz) * step_hz;
const float stop = roundf(g / step_hz) * step_hz;
int steps = roundf((stop - start) / step_hz);
for (int i = 0; i < LO_WORDS; i++)
lo_cos[i] = 0;
dma_channel_config dma_conf = dma_channel_get_default_config(tx_dma);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_32);
channel_config_set_read_increment(&dma_conf, true);
channel_config_set_write_increment(&dma_conf, false);
channel_config_set_ring(&dma_conf, false, LO_BITS_DEPTH + 2);
channel_config_set_dreq(&dma_conf, pio_get_dreq(pio1, 2, true));
dma_channel_configure(tx_dma, &dma_conf, &pio1->txf[2], lo_cos, UINT_MAX, true);
for (int i = 0; i < steps; i++) {
int c = getchar_timeout_us(0);
if ('\n' == c || '\r' == c)
break;
float actual = lo_freq_init(start + i * step_hz);
printf("frequency = %10.6f MHz\n", actual / MHZ);
sleep_ms(x);
}
dma_channel_abort(tx_dma);
return;
}
if (2 == sscanf(cmd, " noise %i %[\a]", &n, tmp)) {
send_init(n);
for (int i = 0; i < LO_WORDS; i++)
lo_cos[i] = rand();
dma_channel_config dma_conf = dma_channel_get_default_config(tx_dma);
channel_config_set_transfer_data_size(&dma_conf, DMA_SIZE_32);
channel_config_set_read_increment(&dma_conf, true);
channel_config_set_write_increment(&dma_conf, false);
channel_config_set_ring(&dma_conf, false, LO_BITS_DEPTH + 2);
channel_config_set_dreq(&dma_conf, pio_get_dreq(pio1, 2, true));
dma_channel_configure(tx_dma, &dma_conf, &pio1->txf[2], lo_cos, UINT_MAX, true);
puts("Transmitting noise, press ENTER to stop.");
while (true) {
int c = getchar_timeout_us(0);
if ('\n' == c || '\r' == c)
break;
for (int i = 0; i < LO_WORDS; i++)
lo_cos[i] = rand();
}
dma_channel_abort(tx_dma);
return;
}
puts("unknown command");
}