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Those GPIO pins can be used for other purposes as well, it depends on the software (configration). The TI solution is like the AD's miniDSP. Problem is getting the (right) PurePath software: http://www.ti.com/tool/PUREPATHCONSOLE You can also use the older PurePath Studio workflow if the PPC3...

Seems this is late but the PCM5242 chips has a built-in DSP, and you could use the GPIO pins as extra I2S data lines to another DAC (sharing the clock lines). That way you could build for an example a 2 in 4 out DSP crossover for active speakers. I see there isn't much space for anything but...

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Seems you probably have to implement a whole new USB UAC2 stack. There aren't many open source implementations available, you can find the XMOS and this SDR-Widget for Atmel processors: https://github.com/borgestrand/sdr-widget Some XMOS code you might have used earlier can be found here...

The shared gain is a great idea. Us the other half of 1k dual pot with the op amp by connecting it from the negative input to ground via another 47 ohms resistor and a largish capacitor (470 uF at least). The feedback resistor sets the maximum gain. Note that you should really use a "C" taper...

Nope. We are not handling power here but just bare voltages, thus the unit is dBu which is exactly 0.775V, and that's what the "Table 1. Maximum output level of microphone (dBu)" referenced earlier uses as the output voltage level measurement unit. Those levels are quite high though, but...

Seriously? The function used in the filter is actually "double tanh (double x)" in C(++, whatever), double means 64-bit floating point, both the parameter and return value are doubles.

The table gives you the maximum output level which for said 20 mv/Pa sensitive microphone will be +4 dBu @130 dB. Please use the dB level to voltage conversion calculator here: http://www.sengpielaudio.com/calculator-db-volt.htm +4 dBu converts to 1.227652988 volts (V) RMS, 3.47232701 volts...

There are some tanh approximations you could try, see for an example this thread on stackexchange: https://math.stackexchange.com/questions/107292/rapid-approximation-of-tanhx or this on kvr vst: https://www.kvraudio.com/forum/viewtopic.php?t=262823

Capacitor and even dynamic mics can put out easily over 1V p-p, even more in front of lets say 100W guitar amp or drum set. With the gain of 50 that means 50V p-p output level. Output level depends on mic sensitivity. See http://www.sengpielaudio.com/calculator-transferfactor.htm for table 1...

The mic pre (1512) should really have a gain control (linear or rev log 10k potentiometer in series with a large capacitor > 1000uF). Even then there can be too much gain when recording loud sources considering there is the second gain stage. That second stage could be left out if you run the...

Can't say anything about the ths472 chip, doesn't look professional audio level one to me. Something like That1512 would be much better choice: https://www.mouser.fi/ProductDetail/THAT/1512P08-U?qs=9Udfh7QmL4sFBLonIQFgcw== ThatCorp has good application notes available. Can't go wrong. Also the...

Does the code in https://forum.pjrc.com/threads/60532-Teensy-4-1-Beta-Test?p=237578&viewfull=1#post237578 work with Teensy 4.0 and audio shield with ESP-PSRAM64H soldered in? Nice to have ethernet, then you can use OSC instead of MIDI for controlling modular synths (assuming you've got some...

We don't know why there are these requirements. Anyway a trivial sampled (not actually sampled but calculated in this case but considered as sample) square wave contains frequency components above Nyqvist thus aliasing (study sampling theory). If you're frequency or actually sample period is...

Problem with the square wave generated that way is that it will be aliased unless the AudioSynthWaveform can produce alias-free waveforms. Using a comparator on aliased trivial square wave would remove all aliasing in analog domain though. If you use comparator on sine wave there is obviously...

Create two sine waves (to left and right channels) with the phase angle you want and then use a comparator to convert the other channel to square wave.

Good to see the problem was solved! You better fork https://github.com/PaulStoffregen/SoundfontDecoder to make the fix, commit it and push it to your github fork and then send Paul the pull request and he will decide what to do with it (isn't this the workflow?). Now when you have got the...

KiCAD seems to have very tight schematic/layout integration, and you can only go in that direction - change schematic in schematic editor ("Eeschema") and import changes into layout (in "Pcbnew"). If you can't do that for an example if there are missing libraries or differences in KiCAD versions...

Please be more specific, which code are you running? Have you tried running the other Teensy audio library demos, do they have this same problem. Soundfonts also have loops which are kind of single cycle waveforms so that's not problem. If you have some own implementation please post you're code...

It might be that also the headphone amplifier is another possible source of noise, see https://forum.pjrc.com/threads/27215-24-bit-audio-boards?p=78831&viewfull=1#post78831 Sometimes on some clock domains there may be artefacts caused by jitter. There are means how to tune the clock...

I think there was an issue with HP of SGTL5000 HP filter, if you disable it you'll get much less noise. http://openaudio.blogspot.com/2017/03/teensy-audio-board-self-noise.html

Thanks for tips, I'll check those china companies. I might still move the codec to I2S2 as it would free up the main I2S for multi-channel use. Unfortunately every connection (I2S lines) from the isolator to Teensy crosses over each other (pinout is reversed kind of). Also for the I2S2 master...

Played little bit in Kicad using whollender CS4272 design files. This PCB is too complicated, it could as well be double layer and without those RF isolators (those are fancy though, I didn't even know such exist). I just edited netlist manually as the input from schematic didn't seem to work...

I think the problem is in the synchronization of the startup. Basically you should first stop all clocks including that of codec's. Next reset the FIFO's, setup the I2S on the host side with DMA and only then enable the I2S receiver, clocks and codec. If the 'wrong' channel (right) is received...

Regarding ADC, there is at least the Cirrus (Wolfson) WM8782 ADC which is quite inexpensive and easy to use chip: https://www.cirrus.com/products/wm8782/ With 0.65mm pitch in 20 pin SSOP is it easy (almost) to solder. It doesn't require special I2C or SPI codec driver either, it uses hardware...

(This is continuum to the closed thread: https://forum.pjrc.com/threads/59113-PT8215-cheap-I2S-A-D) This is good find anyway. PT8211 nor PT8215 are I2S DAC's but relative, they use TDA1545 kind PCM format which is right justified. What makes this good it's current output DAC which makes it...

BLCK is still connected to wrong pin D22 it should go to D21.

Do rather something like this: typedef enum { INT16, INT32, FLOAT } data_type; typedef struct audio_block_struct { uint8_t ref_count; uint8_t reserved1:6; uint8_t data_type_tag:2; uint16_t memory_pool_index; union { int16_t data[AUDIO_BLOCK_SAMPLES]; int32_t...

I guess you could also use RX_DATA1 pin to input data using only single I2S interface, but then you had to enable the input pin and increase the frame size, and the audio library doesn't know anything about that as it expects only two channels, not four interleaved. Maybe that's what the...

AudioInputI2S i2s1; AudioInputI2S i2s2; Is that ok? Shouldn't that be AudioInputI2S i2s1; AudioInputI2S2 i2s2;

What if you just required that the board is powered only using USB, a phone charger for an instance when it's not connected to PC, or connect the +5V socket to VUSB pins (on teensy) directly, they are directly connected anyway. Teensy 4.0 VIN is +5V. You could of course use a small 5V relay...

When I'm looking at the schematics and compare to T4 pins I wonder if there is an error. It looks like that the MCLK pin is connected to correct T4 pin (D23) but the pins SCLK (BLCK), LRCLK, SDA and SCL should been connected to D21 - D18 in that order meaning they have been shifted to D22 - D19...

Eurorack PSU supplies are +/- 12V so that must be the absolute maximum range. Anyway, for CV's some digital interface could make sense more than the analog, how about ADAT I/O?. ES-8 for an example has ADAT interface (https://www.expert-sleepers.co.uk/es8.html). There seems to be a standalone...

There is a nice 8x8 analog I/O board for FreeDSP, the pcb is available from Tindie except that it's not in store right now (the seller is busy doing another FreeDSP project): https://www.tindie.com/products/auverdion/freedspx-analogio-x8/ I guess that would work nice with the Teensy 4.0...

Configuring via pins practically means that you don't wire the I2C or SPI at all and practically hardwire the used PCM mode (I2S, TDM etc.), sample rates, bit depth etc.. Thus no need for codec drivers. Most of the converters have that "parallel interface" anyway, but it's seldom used.

On iMX RT1060 it is possible to use AD_B1_07 pin as SPDIF_EXT_CLK (currently mapped to digital pin 16/AD2) as input (via a mux, that's referred as tx_clk2 in RM) for the MCLK3 source in SA1-SAI3. That would give us possibility to sync the internal clock generation to an external MCLK. For...

Just some thoughts after browsing github. It would be a good start for the 16-bit to whatever bit upgrade if the lower level (I2S and TDM, PCM is not supported, meaning MSB left justified, positive frame sync, no 1 BLCK delay in the beginning of the frame?) drivers supported only 32-bit bit...

Are any of these 32-bit floating point forks working on Teensy 4.0? Also there doesn't seem to be F32 implementation for I2S slave mode...

Ok. However, if you use HW configuration mode for the converters you don't need any special drivers other than for Teensy (which already exists). I hadn't thought the stacking option, that would make it possible to use modular approach. Different modules like a basic stereo codec (AK4558 for...

I think you shouldn't try designing one board for all possible users and use cases. People who need multiple inputs usually want to record some music performance like drum set with multiple microphones. They don't usually need multiple outputs (for independent monitoring maybe it would be nice...

Could you actually run Voyetra MIDI Sequencer Gold on Teensy 4.0 using this emulator? See http://www.vgmpf.com/Wiki/index.php?title=Sequencer_Plus_Gold How about the timing? You should been also able to emulate the MPU-401 MIDI interface in UART mode though some other MIDI interfaces are also...

Check out this one: http://www.embeddedartists.com/products/lpcxpresso/lpclink2.php Looks like your regular USB JTAG, here for the NXP Cortex-M4 controllers (and implemented using a LPC4370), but it is not if you plug in this board: http://www.embeddedartists.com/products/app/labtool.php The...

There are plenty of DAC's and ADC's but without a proper MCLK output or an external PLL it's not worth using them anyway. Also there are a little bit better codecs like AK4556 which might also be reasonable choice for CODEC. Teensy 3.0's Cortex-M4 chip also supports multichannel audio output...

That's a tiny board, maybe too tiny after all. Anyway, for adding memory also consider MRAM of FRAM nv SPI RAM's, might be already fitting the layout. Everspin MR20H40 is the MRAM variant with 512kx8 (512 kbytes) chip which could be used as RAM or EEPROM or whatever, so for you could implement...