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Bidirectional TDM Support #2843

Merged
merged 7 commits into from
Mar 14, 2025
Merged

Bidirectional TDM Support #2843

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f3a7e6f
Initial commit.
efairbanks Mar 10, 2025
449caf6
Works with AK4619 in TDM128 I2S compatibility mode set to rising BCLK.
efairbanks Mar 10, 2025
4d19495
Works with I2S compat mode with BCLK mode set to 0 on AK4619.
efairbanks Mar 10, 2025
4e821e1
Clean up style I2S.cpp
earlephilhower Mar 14, 2025
a265d0d
astyle I2S.cpp
earlephilhower Mar 14, 2025
d5eba81
astyle pio_i2s.pio.h
earlephilhower Mar 14, 2025
0c8db3d
Merge branch 'master' into tdm_bidirectional
earlephilhower Mar 14, 2025
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14 changes: 9 additions & 5 deletions libraries/I2S/src/I2S.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -178,15 +178,15 @@ bool I2S::setLSBJFormat() {
}

bool I2S::setTDMFormat() {
if (_running || !_isOutput || _isInput) {
if (_running || !_isOutput) {
return false;
}
_isTDM = true;
return true;
}

bool I2S::setTDMChannels(int channels) {
if (_running || !_isOutput || _isInput) {
if (_running || !_isOutput) {
return false;
}
_tdmChannels = channels;
Expand Down Expand Up @@ -255,9 +255,9 @@ bool I2S::begin() {
_isHolding = 0;
int off = 0;
if (!_swapClocks) {
_i2s = new PIOProgram(_isOutput ? (_isInput ? &pio_i2s_inout_program : (_isTDM ? &pio_tdm_out_program : (_isLSBJ ? &pio_lsbj_out_program : &pio_i2s_out_program))) : &pio_i2s_in_program);
_i2s = new PIOProgram(_isOutput ? (_isInput ? (_isTDM ? &pio_tdm_inout_program : &pio_i2s_inout_program) : (_isTDM ? &pio_tdm_out_program : (_isLSBJ ? &pio_lsbj_out_program : &pio_i2s_out_program))) : &pio_i2s_in_program);
} else {
_i2s = new PIOProgram(_isOutput ? (_isInput ? &pio_i2s_inout_swap_program : (_isTDM ? &pio_tdm_out_swap_program : (_isLSBJ ? &pio_lsbj_out_swap_program : &pio_i2s_out_swap_program))) : &pio_i2s_in_swap_program);
_i2s = new PIOProgram(_isOutput ? (_isInput ? (_isTDM ? &pio_tdm_inout_swap_program : &pio_i2s_inout_swap_program) : (_isTDM ? &pio_tdm_out_swap_program : (_isLSBJ ? &pio_lsbj_out_swap_program : &pio_i2s_out_swap_program))) : &pio_i2s_in_swap_program);
}
int minpin, maxpin;
if (_isOutput && _isInput) {
Expand All @@ -278,7 +278,11 @@ bool I2S::begin() {
}
if (_isOutput) {
if (_isInput) {
pio_i2s_inout_program_init(_pio, _sm, off, _pinDIN, _pinDOUT, _pinBCLK, _bps, _swapClocks);
if (_isTDM) {
pio_tdm_inout_program_init(_pio, _sm, off, _pinDIN, _pinDOUT, _pinBCLK, _bps, _swapClocks, _tdmChannels);
} else {
pio_i2s_inout_program_init(_pio, _sm, off, _pinDIN, _pinDOUT, _pinBCLK, _bps, _swapClocks);
}
} else if (_isTDM) {
pio_tdm_out_program_init(_pio, _sm, off, _pinDOUT, _pinBCLK, _bps, _swapClocks, _tdmChannels);
} else if (_isLSBJ) {
Expand Down
71 changes: 71 additions & 0 deletions libraries/I2S/src/pio_i2s.pio
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,41 @@ lastbit:
; Loop back to the beginning


.program pio_tdm_inout
.side_set 2 ; 0 = bclk, 1 = wclk
; The C code should place (number of bits * channels - 1) in Y and update SHIFTCTRL
; to be 32 (as per the TDM specs)
; +----- WCLK
; |+---- BCLK
mov x, y side 0b01 [1]
bitloop:
out pins, 1 side 0b00 ; Output changes on falling edge
in pins, 1 side 0b00 ; Sample input on falling edge
jmp x-- bitloop side 0b11 [1] ; Last bit toggles WCLK to mark frame boundary

lastbit:
in pins, 1 side 0b10
out pins, 1 side 0b10
; Loop back to the beginning


.program pio_tdm_inout_swap
.side_set 2 ; 0 = bclk, 1 = wclk
; The C code should place (number of bits * channels - 1) in Y and update SHIFTCTRL
; to be 32 (as per the TDM specs)
; +----- WCLK
; |+---- BCLK
mov x, y side 0b10 [1]
bitloop:
out pins, 1 side 0b00 ; Output changes on falling edge
in pins, 1 side 0b00 ; Sample input on falling edge
jmp x-- bitloop side 0b11 [1] ; Last bit toggles WCLK to mark frame boundary

lastbit:
in pins, 1 side 0b01
out pins, 1 side 0b01
; Loop back to the beginning


.program pio_lsbj_out
.side_set 2 ; 0 = bclk, 1=wclk
Expand Down Expand Up @@ -313,6 +348,42 @@ static inline void pio_tdm_out_program_init(PIO pio, uint sm, uint offset, uint
pio_sm_exec(pio, sm, pio_encode_out(pio_osr, 32));
}

static inline void pio_tdm_inout_program_init(PIO pio, uint sm, uint offset, uint data_in_pin, uint data_out_pin, uint clock_pin_base, uint bits, bool swap, uint channels) {
pio_gpio_init(pio, data_in_pin);
pio_gpio_init(pio, data_out_pin);
pio_gpio_init(pio, clock_pin_base);
pio_gpio_init(pio, clock_pin_base + 1);

pio_sm_config c = swap ? pio_tdm_inout_swap_program_get_default_config(offset) : pio_tdm_inout_program_get_default_config(offset);

sm_config_set_in_pins(&c, data_in_pin);
sm_config_set_out_pins(&c, data_out_pin, 1);
sm_config_set_sideset_pins(&c, clock_pin_base);
sm_config_set_in_shift(&c, false, true, 32);
sm_config_set_out_shift(&c, false, true, 32);
sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_NONE);

pio_sm_init(pio, sm, offset, &c);

pio_sm_set_consecutive_pindirs(pio, sm, data_in_pin, 1, false);
pio_sm_set_consecutive_pindirs(pio, sm, data_out_pin, 1, true);
pio_sm_set_consecutive_pindirs(pio, sm, clock_pin_base, 2, true);
pio_sm_set_set_pins(pio, sm, data_out_pin, 1);
pio_sm_set_set_pins(pio, sm, clock_pin_base, 2);

// Initialize PIO state for TDM
// Can't set constant > 31, so push and pop/mov if needed
if (bits * channels - 1 > 31) {
pio_sm_put_blocking(pio, sm, bits * channels - 2);
pio_sm_exec(pio, sm, pio_encode_pull(false, false));
pio_sm_exec(pio, sm, pio_encode_mov(pio_y, pio_osr));
} else {
pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits * channels - 2));
}

// Need to make OSR believe there's nothing left to shift out
pio_sm_exec(pio, sm, pio_encode_out(pio_osr, 32));
}

static inline void pio_lsbj_out_program_init(PIO pio, uint sm, uint offset, uint data_pin, uint clock_pin_base, uint bits, bool swap) {
pio_gpio_init(pio, data_pin);
Expand Down
104 changes: 104 additions & 0 deletions libraries/I2S/src/pio_i2s.pio.h
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Original file line number Diff line number Diff line change
Expand Up @@ -193,6 +193,80 @@ static inline pio_sm_config pio_tdm_out_swap_program_get_default_config(uint off
}
#endif

// ------------- //
// pio_tdm_inout //
// ------------- //

#define pio_tdm_inout_wrap_target 0
#define pio_tdm_inout_wrap 5

static const uint16_t pio_tdm_inout_program_instructions[] = {
// .wrap_target
0xa922, // 0: mov x, y side 1 [1]
0x6001, // 1: out pins, 1 side 0
0x4001, // 2: in pins, 1 side 0
0x1941, // 3: jmp x--, 1 side 3 [1]
0x5001, // 4: in pins, 1 side 2
0x7001, // 5: out pins, 1 side 2
// .wrap
};

#if !PICO_NO_HARDWARE
static const struct pio_program pio_tdm_inout_program = {
.instructions = pio_tdm_inout_program_instructions,
.length = 6,
.origin = -1,
.pio_version = 0,
#if PICO_PIO_VERSION > 0
.used_gpio_ranges = 0x0
#endif
};

static inline pio_sm_config pio_tdm_inout_program_get_default_config(uint offset) {
pio_sm_config c = pio_get_default_sm_config();
sm_config_set_wrap(&c, offset + pio_tdm_inout_wrap_target, offset + pio_tdm_inout_wrap);
sm_config_set_sideset(&c, 2, false, false);
return c;
}
#endif

// ------------------ //
// pio_tdm_inout_swap //
// ------------------ //

#define pio_tdm_inout_swap_wrap_target 0
#define pio_tdm_inout_swap_wrap 5

static const uint16_t pio_tdm_inout_swap_program_instructions[] = {
// .wrap_target
0xb122, // 0: mov x, y side 2 [1]
0x6001, // 1: out pins, 1 side 0
0x4001, // 2: in pins, 1 side 0
0x1941, // 3: jmp x--, 1 side 3 [1]
0x4801, // 4: in pins, 1 side 1
0x6801, // 5: out pins, 1 side 1
// .wrap
};

#if !PICO_NO_HARDWARE
static const struct pio_program pio_tdm_inout_swap_program = {
.instructions = pio_tdm_inout_swap_program_instructions,
.length = 6,
.origin = -1,
.pio_version = 0,
#if PICO_PIO_VERSION > 0
.used_gpio_ranges = 0x0
#endif
};

static inline pio_sm_config pio_tdm_inout_swap_program_get_default_config(uint offset) {
pio_sm_config c = pio_get_default_sm_config();
sm_config_set_wrap(&c, offset + pio_tdm_inout_swap_wrap_target, offset + pio_tdm_inout_swap_wrap);
sm_config_set_sideset(&c, 2, false, false);
return c;
}
#endif

// ------------ //
// pio_lsbj_out //
// ------------ //
Expand Down Expand Up @@ -490,6 +564,36 @@ static inline void pio_tdm_out_program_init(PIO pio, uint sm, uint offset, uint
// Need to make OSR believe there's nothing left to shift out, or the 1st word will be the count we just passed in, not a sample
pio_sm_exec(pio, sm, pio_encode_out(pio_osr, 32));
}
static inline void pio_tdm_inout_program_init(PIO pio, uint sm, uint offset, uint data_in_pin, uint data_out_pin, uint clock_pin_base, uint bits, bool swap, uint channels) {
pio_gpio_init(pio, data_in_pin);
pio_gpio_init(pio, data_out_pin);
pio_gpio_init(pio, clock_pin_base);
pio_gpio_init(pio, clock_pin_base + 1);
pio_sm_config c = swap ? pio_tdm_inout_swap_program_get_default_config(offset) : pio_tdm_inout_program_get_default_config(offset);
sm_config_set_in_pins(&c, data_in_pin);
sm_config_set_out_pins(&c, data_out_pin, 1);
sm_config_set_sideset_pins(&c, clock_pin_base);
sm_config_set_in_shift(&c, false, true, 32);
sm_config_set_out_shift(&c, false, true, 32);
sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_NONE);
pio_sm_init(pio, sm, offset, &c);
pio_sm_set_consecutive_pindirs(pio, sm, data_in_pin, 1, false);
pio_sm_set_consecutive_pindirs(pio, sm, data_out_pin, 1, true);
pio_sm_set_consecutive_pindirs(pio, sm, clock_pin_base, 2, true);
pio_sm_set_set_pins(pio, sm, data_out_pin, 1);
pio_sm_set_set_pins(pio, sm, clock_pin_base, 2);
// Initialize PIO state for TDM
// Can't set constant > 31, so push and pop/mov if needed
if (bits * channels - 1 > 31) {
pio_sm_put_blocking(pio, sm, bits * channels - 2);
pio_sm_exec(pio, sm, pio_encode_pull(false, false));
pio_sm_exec(pio, sm, pio_encode_mov(pio_y, pio_osr));
} else {
pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits * channels - 2));
}
// Need to make OSR believe there's nothing left to shift out
pio_sm_exec(pio, sm, pio_encode_out(pio_osr, 32));
}
static inline void pio_lsbj_out_program_init(PIO pio, uint sm, uint offset, uint data_pin, uint clock_pin_base, uint bits, bool swap) {
pio_gpio_init(pio, data_pin);
pio_gpio_init(pio, clock_pin_base);
Expand Down