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Merge pull request #1419 from bdring/BetterI2SClockingCopy
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Better i2 s clocking redux
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@bdring
bdring authored Dec 31, 2024
2 parents 4984788 + 728ad6d commit c692589
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Showing 4 changed files with 47 additions and 59 deletions.
97 changes: 39 additions & 58 deletions FluidNC/esp32/i2s_engine.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,7 @@

#include "esp_intr_alloc.h"

/* 32-bit mode: 1000000 usec / ((160000000 Hz) / 5 / 2) x 32 bit/pulse x 2(stereo) = 4 usec/pulse */
const uint32_t I2S_OUT_USEC_PER_PULSE = 2;
uint32_t i2s_frame_us; // 1, 2 or 4

static volatile uint32_t i2s_out_port_data = 0;

Expand All @@ -42,10 +41,6 @@ static pinnum_t i2s_out_ws_pin = 255;
static pinnum_t i2s_out_bck_pin = 255;
static pinnum_t i2s_out_data_pin = 255;

//
// Internal functions
//

static inline void i2s_out_reset_tx_rx() {
i2s_ll_tx_reset(&I2S0);
i2s_ll_rx_reset(&I2S0);
Expand Down Expand Up @@ -125,7 +120,7 @@ static int i2s_out_start() {
i2s_out_reset_tx_rx();
i2s_out_reset_fifo_without_lock();

i2s_ll_tx_set_chan_mod(&I2S0, I2S_CHANNEL_FMT_ONLY_LEFT);
// i2s_ll_tx_set_chan_mod(&I2S0, I2S_CHANNEL_FMT_RIGHT_LEFT);
i2s_ll_tx_stop_on_fifo_empty(&I2S0, true);
i2s_ll_tx_start(&I2S0);

Expand Down Expand Up @@ -159,10 +154,11 @@ static int i2s_out_start() {

static bool timer_running = false;

// i2s_out_delay() is used by synchronous_write(), to ensure that that
// the newly-written data has arrived at the shift register output
void i2s_out_delay() {
delay_us((FIFO_LENGTH + FIFO_RELOAD) * (I2S_OUT_USEC_PER_PULSE / 2));
// Depending on the timing, it may not be reflected immediately,
// so wait twice as long just in case.
uint32_t wait_counts = timer_running ? FIFO_THRESHOLD + FIFO_RELOAD : 2;
delay_us(i2s_frame_us * wait_counts);
}

void IRAM_ATTR i2s_out_write(pinnum_t pin, uint8_t val) {
Expand All @@ -189,6 +185,8 @@ int i2s_out_init(i2s_out_init_t* init_param) {
return -1;
}

i2s_frame_us = init_param->min_pulse_us;

i2s_out_port_data = init_param->init_val;

// To make sure hardware is enabled before any hardware register operations.
Expand Down Expand Up @@ -237,77 +235,60 @@ int i2s_out_init(i2s_out_init_t* init_param) {
i2s_ll_enable_camera(&I2S0, false);
#ifdef SOC_I2S_SUPPORTS_PDM_TX
i2s_ll_tx_enable_pdm(&I2S0, false);
i2s_ll_rx_enable_pdm(&I2S0, false);
#endif

i2s_ll_enable_dma(&I2S0, false);

i2s_ll_tx_set_chan_mod(&I2S0, I2S_CHANNEL_FMT_ONLY_LEFT);

#if I2S_OUT_NUM_BITS == 16
i2s_ll_tx_set_sample_bit(&I2S0, I2S_BITS_PER_SAMPLE_16BIT, I2S_BITS_PER_SAMPLE_16BIT);
i2s_ll_rx_set_sample_bit(&I2S0, I2S_BITS_PER_SAMPLE_16BIT, I2S_BITS_PER_SAMPLE_16BIT);
#else
i2s_ll_tx_set_sample_bit(&I2S0, I2S_BITS_PER_SAMPLE_32BIT, I2S_BITS_PER_SAMPLE_32BIT);
i2s_ll_rx_set_sample_bit(&I2S0, I2S_BITS_PER_SAMPLE_32BIT, I2S_BITS_PER_SAMPLE_32BIT);
i2s_ll_tx_enable_mono_mode(&I2S0, true);
i2s_ll_rx_enable_mono_mode(&I2S0, true);
// Data width is 32-bit. Forgetting this setting will result in a 16-bit transfer.
#endif
// I2S0.conf.tx_mono = 0; // Set this bit to enable transmitter’s mono mode in PCM standard mode.
i2s_ll_tx_set_chan_mod(&I2S0, I2S_CHANNEL_FMT_RIGHT_LEFT); // Overridden by i2s_out_start

i2s_ll_rx_set_chan_mod(&I2S0, 1);
// i2s_ll_rx_set_chan_mod(&I2S0, I2S_CHANNEL_FMT_ALL_LEFT, false);
// I2S0.conf.rx_mono = 0;
i2s_ll_tx_set_sample_bit(&I2S0, I2S_BITS_PER_SAMPLE_32BIT, I2S_BITS_PER_SAMPLE_16BIT);
i2s_ll_tx_enable_mono_mode(&I2S0, false);

i2s_ll_enable_dma(&I2S0, false); // FIFO is not connected to DMA
i2s_ll_tx_stop(&I2S0);
i2s_ll_rx_stop(&I2S0);

i2s_ll_tx_enable_msb_right(&I2S0, true); // Place right-channel data at the MSB in the transmit FIFO.
i2s_ll_tx_enable_msb_right(&I2S0, true); // Place right-channel data at the MSB in the transmit FIFO.

i2s_ll_tx_enable_right_first(&I2S0, false); // Send the left-channel data first
// i2s_ll_tx_enable_right_first(&I2S0, true); // Send the right-channel data first

i2s_ll_tx_set_slave_mod(&I2S0, false); // Master
i2s_ll_tx_force_enable_fifo_mod(&I2S0, true);
#ifdef SOC_I2S_SUPPORTS_PDM_RX
i2s_ll_rx_enable_pdm(&I2S0, false);
#endif
#ifdef SOC_I2S_SUPPORTS_PDM_TX
i2s_ll_tx_enable_pdm(&I2S0, false);
#endif

// I2S_COMM_FORMAT_I2S_LSB
i2s_ll_tx_set_ws_width(&I2S0, 0); // PCM standard mode.
i2s_ll_rx_set_ws_width(&I2S0, 0); // PCM standard mode.
i2s_ll_tx_enable_msb_shift(&I2S0, false); // Do not use the Philips standard to avoid bit-shifting
i2s_ll_rx_enable_msb_shift(&I2S0, false); // Do not use the Philips standard to avoid bit-shifting

// i2s_set_clk

// set clock (fi2s) 160MHz / 5
#ifdef CONFIG_IDF_TARGET_ESP32
i2s_ll_tx_clk_set_src(&I2S0, I2S_CLK_D2CLK);
#endif
// N + b/a = 0
#if I2S_OUT_NUM_BITS == 16
// N = 10
uint16_t mclk_div = 10;
#else
uint16_t mclk_div = 3;
// N = 5
// 5 could be changed to 2 to make I2SO pulse at 312.5 kHZ instead of 125 kHz, but doing so would
// require some changes to deal with pulse lengths that are not an integral number of microseconds.
#endif
i2s_ll_mclk_div_t first_div = { 2, 3, 47 }; // { N, b, a }
i2s_ll_tx_set_clk(&I2S0, &first_div);

i2s_ll_mclk_div_t div = { 2, 32, 16 }; // b/a = 0.5
// i2s_ll_mclk_div_t first_div = { 2, 3, 47 }; // { N, b, a }
// i2s_ll_tx_set_clk(&I2S0, &first_div);

i2s_ll_mclk_div_t div = { 5, 0, 0 };
switch (i2s_frame_us) {
case 1:
div.mclk_div = 2; // Fractional divisor 2.5, i.e. 2 + 16/32
div.a = 32;
div.b = 16;
break;
case 2:
div.mclk_div = 5;
break;

case 4:
default:
div.mclk_div = 10;
break;
}
i2s_ll_tx_set_clk(&I2S0, &div);

// Bit clock configuration bit in transmitter mode.
// fbck = fi2s / tx_bck_div_num = (160 MHz / 5) / 2 = 16 MHz
i2s_ll_tx_set_bck_div_num(&I2S0, 2);
i2s_ll_rx_set_bck_div_num(&I2S0, 2);

// Remember GPIO pin numbers
i2s_out_ws_pin = init_param->ws_pin;
Expand Down Expand Up @@ -414,15 +395,15 @@ static uint32_t init_engine(uint32_t dir_delay_us, uint32_t pulse_us, uint32_t f
_pulse_func = callback;
i2s_fifo_intr_setup();

if (pulse_us < I2S_OUT_USEC_PER_PULSE) {
pulse_us = I2S_OUT_USEC_PER_PULSE;
if (pulse_us < i2s_frame_us) {
pulse_us = i2s_frame_us;
}
if (pulse_us > I2S_MAX_USEC_PER_PULSE) {
pulse_us = I2S_MAX_USEC_PER_PULSE;
}
_dir_delay_us = dir_delay_us;
_pulse_counts = (pulse_us + I2S_OUT_USEC_PER_PULSE - 1) / I2S_OUT_USEC_PER_PULSE;
_tick_divisor = frequency * I2S_OUT_USEC_PER_PULSE / 1000000;
_pulse_counts = (pulse_us + i2s_frame_us - 1) / i2s_frame_us;
_tick_divisor = frequency * i2s_frame_us / 1000000;

_remaining_pulse_counts = 0;
_remaining_delay_counts = 0;
Expand All @@ -433,7 +414,7 @@ static uint32_t init_engine(uint32_t dir_delay_us, uint32_t pulse_us, uint32_t f
start_timer();
set_timer_ticks(100);

return _pulse_counts * I2S_OUT_USEC_PER_PULSE;
return _pulse_counts * i2s_frame_us;
}

static int init_step_pin(int step_pin, int step_invert) {
Expand Down Expand Up @@ -480,7 +461,7 @@ static int IRAM_ATTR start_unstep() {
static IRAM_ATTR void finish_unstep() {}

static uint32_t max_pulses_per_sec() {
return 1000000 / (2 * _pulse_counts * I2S_OUT_USEC_PER_PULSE);
return 1000000 / (2 * _pulse_counts * i2s_frame_us);
}

// clang-format off
Expand Down
1 change: 1 addition & 0 deletions FluidNC/include/Driver/i2s_out.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ typedef struct {
pinnum_t data_pin;
uint32_t pulse_period; // aka step rate.
uint32_t init_val;
uint32_t min_pulse_us;
} i2s_out_init_t;

/*
Expand Down
6 changes: 5 additions & 1 deletion FluidNC/src/Machine/I2SOBus.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@

namespace Machine {
void I2SOBus::validate() {
Assert(_min_pulse_us == 1 || _min_pulse_us == 2 || _min_pulse_us == 4, "min_pulse_us must be 1, 2 or 4");
if (_bck.defined() || _data.defined() || _ws.defined()) {
Assert(_bck.defined(), "I2SO BCK pin should be configured once");
Assert(_data.defined(), "I2SO Data pin should be configured once");
Expand All @@ -18,10 +19,11 @@ namespace Machine {
handler.item("bck_pin", _bck);
handler.item("data_pin", _data);
handler.item("ws_pin", _ws);
handler.item("min_pulse_us", _min_pulse_us);
}

void I2SOBus::init() {
log_info("I2SO BCK:" << _bck.name() << " WS:" << _ws.name() << " DATA:" << _data.name());
log_info("I2SO BCK:" << _bck.name() << " WS:" << _ws.name() << " DATA:" << _data.name() << "Min Pulse:" << _min_pulse_us << "us");

// Check capabilities:
if (!_ws.capabilities().has(Pin::Capabilities::Output | Pin::Capabilities::Native)) {
Expand All @@ -40,6 +42,8 @@ namespace Machine {
params.data_pin = _data.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
params.init_val = 0;

params.min_pulse_us = _min_pulse_us;

i2s_out_init(&params);
}
}
Expand Down
2 changes: 2 additions & 0 deletions FluidNC/src/Machine/I2SOBus.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@ namespace Machine {
Pin _data;
Pin _ws;

uint32_t _min_pulse_us = 2;

void validate() override;
void group(Configuration::HandlerBase& handler) override;

Expand Down

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