mborgerson
Senior Member

I'm not sure those are the parts I found by stepping through the DigiKey search process, but I'm strongly biased toward them. It was DigiKey that made it possible for me to start a small board production facility early...

The last time I played around with the ARM CMSIS FFT on the Teensy it was with the T3.6. I found that a Real FFT took about 1.02mSec for FFT1024 with a Hanning window. A friend is working over the same calculations...

I just transferred a solar energy evaluation program from the T3.6 that I used last summer to the T3.5. I ran into some compilation issues in MTP.h and MTP.cpp in the tests for processor type: #if...

I dug out my LT1867L board and recorded a data file with all 8 channels connected to a 1.5V alkaline battery and sampled at 4000 samples/second. Data from each of the first four channels passed through an 8-pole IIR...

The LT1867 is a capacitive Successive Approximation ADC. The input acquisition time is a nominal 1.1 microseconds, independent of the sample rate. As noted, it is imperative to have good anti-aliasing filters at...

I've used an LT1867 board from another project to successfully collect data on the T3.6. Here is the part of the code that interacts with the LT1867: /**************************************************************...

Or you could consider using an SD File that is pre-allocated. This avoids the necessity for the file system to scan the FAT to find the next file cluster.

Excellent point. I've gone so far as to add a label to the silkscreen for things like SCK, MOSI, MISO, etc. etc. The vias generally take less than half the PCB area of a normal test point. Some of my smaller vias...

That was my thought too. A closer examination of the timing of the low-current part shows that those periods last about the same interval as the timing info shows for an average update of the ILI9341 (about 41mSec). ...

Been there, done that. I got past the problem at the prototype stage by finding a convenient place to cut the traces and do an "X" set of jumpers to switch the signals. I've also added pull-ups by finding a...

Funny you should ask! A few days ago, I had a setup to measure power consumption of the T4.1 while writing to the SD Card. The setup uses a high-side current sensor on the T4.1 power input and measures the current at...

I took a quick look at the GitHub repository and I will probably try implementing it later today. A few things still bother me: 1. The endpoint definitions are different between the T3 and T4 cores in usb_desc.h:...

In a post on this thread: https://forum.pjrc.com/threads/66265-Fastest-way-to-transfer-data-to-from-Teensy-4-0-4-1-and-Windows-10 I gave examples of python scripts and a Teensy 4.1 sketch that transferred data to...

FWIW, I've attached a PDF schematic from a data logger from about 12 years ago---back when 32GB SD cards were the largest available and cost $50 to $75 dollars each. We needed 128GB of storage, so I designed a...

Luni: Feel free to put the python scripts on the wiki page.

Using all three I2C ports may give you 3x the sampling rate that you would get with a multiplexer. Answering the following questions might get more complete responses: 1. What are your desired and minimum...

Rather than post hundreds of lines of C++ Builder code that you could build to illustrate data transfers that take only a few dozen lines, I bit the bullet and came up with a couple of Python scripts. The first script...

I've had good results transferring data at rates over 10MB/second using the USB Serial port. I've recently found that it makes things simpler to use the USB Dual Serial setup. I use SerialUSB1 for the data transfers...

I think a neat approach would be to build your own switch with some brass sheet stock from the local hobby shop: T___________NUT_ ^____________G The 'T' is a terminal for a switch input on your...

Tested B6 with Radiohead library and two NRF24LO1 modules with LNA and power amplifiers. Good comms between T4.0 and T4.1 at default power and SPI settings over about 30 feet inside the house. The Teensies and...

Installed on Win10x64 Home. All the following compiled and ran on T4.1 without problems (except the ever present warning about using Timelib.h vs Time.h): OV7670 Camera test with JPG compression and SerialUSB1...

I stripped down a logger I wrote some time ago to the bare bones: * Open SD file * write binary records consisting of timing data and 5 ADC values to a buffer * when buffer is full, swap collection to another...

Using the default Teensy Serial USB, I can send about 22MB/second to my PC data logger host app. Your host application has to be optimized for data transfer---the only screen output I use is a byte count about once per...

You could get 75MHz by setting analogoutfrequency on a PWM-capable pin. I think that's as high as you can go as it is 1/2 the bus frequency of 150MHz. Perhaps you could get 80MHz by overclocking the T4.1, but that...

I've created a GitHub repository with the Slideshow library. The repository has the Slideshow class, an example program, and 5 files that are used by the example program. The repository is here: ...

The open once, write and flush many times, close once process is more efficient with larger writes to SD. When you do small writes, like your 64 bytes, it is not so efficient, as the system has to merge and write a...

I figured out how to get a better video of the slide show transition. This video was taken from the display of the slide show app I plan to post on GitHub tomorrow. This whole thing about posting videos on line...

I think I'll have it on GitHub sometime tomorrow. The code seems pretty stable now, but I need to clean up excess debug statements and add some documentation. I suppose I could add a few more types of transitions...

Rather than opening and closing the files, you could simply call the flush() function. That function writes currently buffered data to the SD and updates the length in the directory. IIRC, it is significantly...

An important thing to remember is that the SD write routines in the latest version of SD (which is actually like SDFAT 2.0B under the hood) takes only a handful of microseconds to write to the SD card. It blocks...

Okay, here is a video from a slide show run on the T4.1 and using the pixel pipeline for transitions and pan and zoom effects during slide display. The video quality is poor------it was filmed with an IPhone...

Could you just divide the input signal by two with an appropriate flip-flop or counter IC? You would lose some resolution, but you would not have to worry about messing with the software innards of the frequency...

I assume that you are driving the sensor with 5V and ground for your power. The outputs should be at about 2.5V each. The T4.1 ADC has an input limit of about 3.3Volts, so you probably need a design that offsets the...

The output data from the 1MSample logger is a binary file with a sequence of 16-bit unsigned integers. Each integer can have a value between 0 and 4095, which represents the range of values output by the ADC in 12-bit...

I think Google is the only one where I have an account. I'll see what I need to do for that. I wonder if I could put the video on my GitHub account, along with the code and demo .BMP files. I've never tried to...

Unfortunately, your circuit diagram illustrates a major problem with direct connection of Wheatstone bridges. They often present several K Ohms of impedance at the ADC inputs. This can slow the response of the circuit...