Recent content by J_Sanders

OK, I did some homework on M.2 (which I probably should have done before posting!). It's a larger industry standard than I realized - and fair to assume it would have been axed by now if reliability were an issue.

Hi all, I have a naïve question. I have never developed a board with a socket that directly interfaces with PCB pads. I grew up blowing into Nintendo cartridges to make games run, so I have an irrational fear of sockets for applications that require long term performance (10y+). Of course, in...

IMPORTANT: Please use the updated OSHPark links in the PCB Readme, here.

I just posted v1.1 of this board in the repository, solving the previous stability issue with DAC2 HD. The fix was to add a 4-component USB power supply filter borrowed from an FTDI circuit note, figure 2.5 here. As of now, there are no known issues with the interface - and the audio quality is +++

For the record, I started a thread on this topic here. I'm currently using a workaround on the MATLAB side that loops the serial read and write functions with no more than 200 bytes per read or write. The effective data transmission rate is ~20Mbps using PsychToolbox IOPort instead of MATLAB's...

Awesome, thanks Frank! A small update - I discovered that the crackling issue on the top-mount version of the board only affects DAC2 HD - not DAC2 Pro or DAC+. I've updated OSHpark and Github notes to reflect this. The solution turned out to be power supply decoupling - a 10uf ceramic...

Hi all, I'm hoping to learn whether someone has already developed a function to set the drive strength, speed and other configurable parameters of Teensy digital pins (esp. T4.0 and 4.1) Something like setDriveStrength(Pin, Level) If not, is there a thread or resource explaining how to do it...

I added example USB Passthrough sketches for DAC2 Pro and DAC2 HD. This effectively turns either HiFiBerry board into a 44.1kHz 16-bit USB sound card for the PC. To load these example sketches, you must select 'Audio' from Tools > USB Type in Arduino IDE...

And I'll be darned. It WAS a ground loop. The glitches are gone if I record with the NI board on my laptop while the Teensy is powered from a different PC. Thanks Paul!!

I had assumed that the spikes were driven by digital noise in the I2S signal - but you do make a good point about my sanity check - the NI USB card and the ASUS Xonar U7 were both grounded to the same USB hub as the Teensy board. It would be really strange if toggling pin 44 but not others...

I don't suspect a current issue - why would pin44 cause more current to be drawn by an audio board than the other built-in SD pins? If the line out has digital filtering enabled somewhere by default, it could suppress the spikes...

Oddly enough, no! At first pass, the line out pins don't seem to have the issue. I expected to see it, since I saw them on the headphone channel and two separate PCM series audio DACs. Does the line out have any filtering enabled by default? I didn't realize that volume() controls a headphone...

I found a reason why it may have evaded detection: At full volume on the SGTL (sgtl5000_1.volume(0.8);), the glitch is masked almost entirely by the noise floor: It's more salient at sgtl5000_1.volume(0.7): And at sgtl5000_1.volume(0.5): So the interference really only manifests if you...

OK, maybe it's a typo in the pinout diagram. I was hoping not! I should add - this glitch is practically inaudible to me with headphones at standard listening levels. The glitches are only 2-3x the noise floor in amplitude. To hear them, you'll need to amplify. I discovered the SD interference...

Hi Frank, For all tests except for I2S2, I plugged the Teensy 4.1 board directly into the Teensy audio board using pin headers. From the pinout diagram, it looks like pin 44 is a clock pin for SDIO mode (light blue) and a chip select pin for SPI2 bus (green). The CS line toggles far slower...