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May I ask two question? I have some asm code from the 80s (on paper). So, I simply can type it in and is should work, right? Also, I recall that one of the nice features of the Z80 was that it had 2 independent register sets, so that context switching was fast. Is that also implemented?

I second Paul's item high performance ADC chip (not audio focused) battery power / management power over ethernet lower priority single pair ethernet or ethercat wifi

I use MTP.reset() when informing PC to reset the MTP connection. This is useful when Teensy is writing to disk while connected to PC, as PC will not be aware of new files and will never enquire. There are multiple ways of informing PC that Teensy files have changed. -MTP.reset() which original...

yes, for example a dual microSD card reader will show up as two devices, even without SD card inserted

Or your use (cabling,etc) of the RTC battery

I have frequently used 1TB SD cards formatted with a PC (exFAT)

I noticed (on T4.1) similar missing early print statements where I was waiting for serial to come up and printed some text that never showed up. In the end it turned out, that the Win PC (in my case, not Mac) enumerated USB so that Serial was available, but was still busy with other...

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 the consumption. Not sure if that can be done with...

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)); Serial.println(SPI2.pinIsMOSI(45))...

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 the timeseries, use the FFT module and inspect the...

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 drivers, per se, may not help to understand 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 Arduino/Teensyduino, however, simplifies the setup and use...

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 (audio tool) and nearly no-coding. You only may...

@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 boot. To test this simply touch prog pin t with VBAT.

@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 and combine the frequencies. For this to work...

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 recommended as the powerup sequence of Teensy is...

@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 teensy) Teenys connected to PC (Vin-VUSB cut)...

Without modifying the library source code, you could insert a queue object, which has a begin() and end() method. It may do what you wanted.

As this discussion already happened some years ago, I repeat my suggestion to elongate the d+ d- pads to make the more solder friendly. That would IMHO be sufficient for most cases. Through holes invite to complex wiring, reducing possible throughput.

If you need the last two bits, you cannot use the optimized 16 bit DSP, then, AFAIK, there are no special DSP optimizations. Or you give up the top 2 bits and modify the Audiolibrary to extract you the 16 bits of interest,

Put the solder back between red pin (VIN) and the Pad. Or apply 5 V to the red pin (VIN). What you have done is equivalent to cutting the connection between the two pads (separating VIN from VUSB)

As the last two bits are anyway noise, to could easily use the teensy audio library that is optimized for 16 bit DSP. Nothing specific for T4. A 1k FFT is already implemented. To make a 8k FFT, you could easily extend the 1 k FFT module to 8k.

OK, if you really wanted to use 16 bit that is optimized for 16 bit integer DSP, with a T4 having float32 and float64 processors then... BUT, these optimizations have not changed from CMSIS4 or earlier to CMSI5

Yes, If you look to the butterfly operations you see a one-to-one relation to the math as given in the comment above every instruction. The differences, for example radix 4 to radix8 is simply programming style but not specific to processor architecture. We all know that loop unwrapping will...

There is not very much CMSIS optimization for T4. FFT is plain float multiplications-addition that are typical for all FFT implementations. 16-bit integer FFT for T3 are different. Here you find DSP optimization (as implemented in Audio Library). If you wanted to do 8 k FFTs then you leave the...

What I like about the history is that IIRC the name Unix was chosen to indicate singe user single task operating system to run on a small computer. contrary to the mainframes at that time. And BTW Linux is Linus Thorwalds Unix (kernel) implementation coming slightly after A. Tannenbaum's Minix...

And you soldered the connection, right?

OK, missed that this were Read tests, so using this for buffering would require read/write access.

Which would be not a problem for a fast data logging program with producer/consumer queue to buffer latencies of uSD cards.

So, that would allow to use PSRAM also with T4.0, or do I mis-undertand the flexibility?

Yes, I know and there are some things better done in MTP-Teensy, but that is what progress is about and I'm happy that Paul, who kickstarted my interest in MTP, finally found some time to work on it to get rid of the experimental tag (@Paul: we still need some unique PID for MTP-Serial)

MPT.loop() simply communicates with PC and handles USB-MTP-requests. Each call to MTP.loop() handles a single MTP request by PC. Other USB requests by PC and Teensy (e.g. USB-Serial) are handled in parallel (transparently). USB per se is handled at an elevated priority level. Running MTP-loop...

Makes sense, as there was no mechanism in place to detect storage removal, or to 'error' handle the absence of a disk.

run MTP.loop() in loop() (lowest priority) and if ADC is running on elevated priority then there is no issue, Anyhow, I, myself, only call MTP.loop() when ADC is stopped, or I'm not interested in captured data. MTP_teensy may run MTP.loop using a 20Hz timer: I would stop this timer during...

That is a good point. Detecting disk removal/insertion is one aspect, but content management on responder (teensy) is another one. The original MTP version had the index file on the disk, so it was easy to synchronize index file with disk related mtp actions and after reset, the file was simply...

OK, the actual derived class (in common/ArduinoFiles.h) is /** * \class PrintFile * \brief PrintFile class. */ template<class BaseFile> class PrintFile : public print_t, public BaseFile { public: using BaseFile::clearWriteError; using BaseFile::getWriteError; using BaseFile::read...

Using TD on Arduino2.0.3/4 on Windows11, I got this Icon, missing the program and reboot icon. Is that normal behavior?

So, I get this warning (using Makefile and GCC 13.3.1 ) : In file included from \Users\zimme\AppData\Local\Arduino15\packages\teensy/hardware/avr/0.60.2/cores/teensy4/Stream.h:24, from...

figure out the interrupt level and check if more important task are processed at higher interrupt level. Interrupt level processing requires considerations of all other tasks. Also, ANY interrupt level processing will block main setup() and loop() functions. Having said that interrupt level...

but a reprogramming and factory-reset button. short press: reload program from PC (must be connected to Teensy) 15 s press: erase all flash and copy original blink program into correct flash position and restart To shutdown Teensy connect on-off pin to GND for ~5 s. To wake-up Teensy connect...

Really? Do you wanted to hear: "go to school!" ?

looks like robot to collect answers to train LLM

Also the SPH0645 (especially the board from Adafruit) needs some 'tolerant' users (large negative offset) DMA does give a fixed delay , so only 'jitter' is driven by asynchronous frame-sync.

You cannot change the Teensy bootloader, which is on a dedicated chip. This is by design, but you can, as others have done, write a secondary bootloader, that resides in your program and allows updating the flash on Teensy. If you use WiFi with ESP32, you need to pass hexcode from ESP32 to...