WMXZ

So, there seems to be no way to use the on-board SD disk with SPI. Why I'm interested in using a slower SPI, is that with SPI and CS I can deactivate the SD disk between writes by simply putting SPI into shared mode, which significantly reduces...

I can easily access the on-board SD card of T4.1 using standard sdio. Now I wanted to test it using the SPI interface (I guess SPI2) However, the following code Serial.println(SPI2.pinIsChipSelect(46)); Serial.println(SPI2.pinIsMISO(43))...

To see the available pins go to "micropython\ports\mimxrt\boards\TEENSY4\pins.csv" (for example on github) where in column A you see the names you can use (here D24 and D25 without 'minus' or 'underscore')

Are you sure that 'O-24' and 'O-25' is the right syntax. Never have seen such in python. Assume you have the latest firmware you should have something like 'D24' and 'D25'

yes, please provide full program (using the </> code tag), as the error is not in the python snippet

Suggest to check the time series of the acoustic data. Some (or all?) I2S mems seem to be DC-coupled before ADC and have terrible DC-offset and DC-drifts. As a consequence they lost the dynamic range one would expect. Alternatively to checking...

Unwanted Audio noise depends heavily on the wiring of the analog part. Especially the power supply of the analog frontend. They easily can pickup electronic noise (highspeed data transmission, etc) via air and via electric interferences. The...

Only two small modifications to Michael's valid answer: You do not NEED to install or use Arduino/Teensyduino. I'happily use Makefiles with hand installed C++ toolchain and Teensy libraries and use Teensy.exe for downloading. Installing...

While basic Circuitpython firmware for T4.1 is available, there is not very much development/support. Knowing the quality support you can find on this forum, I would suggest to use Teensyduino (based on Arduino). The acquisition chain is trivial...

@VictorFS I have no idea on the cause-effect chain, but without pull-up of the program pin this particular system will not boot.

It may, or may not be related, but for one of my systems T4.1 does only boot (from hibernate or power plug-in), if Program pin is pulled high. I do this with a 68 k resistor. It seems that the boot chip, to which prog pin is connected, inhibits...

@h4yn0nnym0u5e , I guess your approach is not good, and is destroying the spectrum. For an 1024 point FFT you need 1024 points spanning 8 blocks of 128 samples. Of course, you can construct your own algorithm and process the 8 blocks individually...

Sorry, but could explain the algorithm how you distribute, say a 1024 point FFT over eight 128 data blocks (i.e. 8 update() calls). This is not obvious from the code, at least to me.

USB connection does NOT require 5V, only D+,D- and GND. A lot of people cut the USB-5V in the cable instead of the VIN-VÙSB Pad connection. 2nd, You should power Teensy with 5V either from USB or VIN. Powering with 3.3V (Bypassing the LDO) is NOT...

@tician, did you really check that you have in your DMA_ISR the "arm_dcache_delete(...)" line to clear the cache as indicated by @jmarsh?

I have a weird power startup issue. system: T4.1 to be powered by 5V (4-alcaline D-cells) with Pololu D24V10F5 DC/DC converter Attached to Teensy are custom ADC attached to Battery in parallel to DC/DC converter is a Preamp (to be switched on by...