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I have my Teensy 4 connected to a data acquisition system. For a variety of reasons, I'd like to power the Teensy with an external power source. But I also need to transfer data through USB. If I cut the trace on the bottom of the Teensy PCB, will I still be able to transfer USB data but...

Thanks Paul. I'll take a look at this.

When Teensy 4.0 and 4.1 first came out, it was possible to access the entire 512k of RAM2 space using the DMAMEM call. Sometime between then and now, an upgrade to Teensyduino reduced the amount of space allocatable to about 510k or so. I'm wondering there is a way get full access to the 512k...

It seems this was the problem. Obviously I never saw that TeensyLoader was still open. Thanks a lot Paul!

Good suggestion. Well, I tried two USB other cables and I get the same problem. I have also tried to upload the blink sketch to a Teensy 4.0 and this works. I think the 4.0 uses the same 480 Mbps USB as 4.1 So it really does seem to be a Teensy 4.1 issue. The TeensyLoader doesn't even pop up...

I just bought 4 Teensy 4.1's and am getting errors uploading to all of them. I am running MacOS 1.13.6 and a clean installation of Arduino 1.8.12 and have installed TeensyDuino 1.52. When attempting to upload a simple blink code, it compiles, but then returns the error about not uploading. I...

So does this mean you can transfer between a Teensy and a host PC using High Speed USB (ie, 480 Mbps)? What kind of transfer speed are you getting? Is your code available?

Thanks, this should be fine when all I need to do it write out data. However, at other points in my code (not shown here), I have to write out blank data, but read back the MISO data. Again, your suggestion would work, however, the problem with using the SPI CS is that I need to check the...

Thanks a lot, KurtE, I'll take a look at this. I do need the CS to deassert itself every write, but I'll have to confirm this. I'm interfacing with some hardware that fills a 1024 event (24 bits event) FIFO and empties it via SPI. I'll give this a try regardless and see how it compares. I...

I do call this function multiple times and so yes, there are gaps between repeated calls. I'm not sure how to reduce this though as I don't want to call the function again and clear the queue prior to the last byte being sent. Is there a better way?

OK, thanks for your response. I'll keep working on this to reduce the gap between words.

This is great, however I think it will only work if the number of bytes to transfer is a multiple of 2? I have the situation where I need to send 24 bit words to the SPI. I currently do this using an 8 bit and an 16 bit transfer, with a SPI_PUSHR_CONT on the first transfer. I am still getting a...

Haven't looked at other brands yet. I have only a 16 GB Lexar Class 10 on hand, but this might be worth looking into. I'm very impressed with T3.6 so far and very glad I jumped in the KS campaign. Thanks.

Good to know, thank you. I am using the Teensy to acquire high speed data via SPI from a piece of hardware and am looking at ways to save it or send it quickly to a PC. I've previously used Serial USB for transfer, but at 12Mbps, it is not fast enough. I was hoping SD might be faster (and it...

I am using the uSDFS-master library to write data to the SD card on T3.6. It works for the most part, but I am noticing that occasionally I get very long delays in writing data. As a test, I am writing 32768 byes to an open file. Usually, this process takes about 3000us, but sometimes will...

Quick update: It appears the 3T magnetic field isn't the culprit, but the RF is. This is probably not surprising. It appears we are getting large 10V spike in the USB power in, that is frying the Teensy. Not sure why it's not frying the PC, but it may be more protected against these things...

Yes, this goes without saying. We have no intention of creating a medical device for use in humans. Understandably, there are a lot of regulations that need to be followed for medical devices. This is not the issue here. We are basic scientists working on an idea at his point. You have to...

This is good to know, thanks. We are using the USB to power it.

Thanks drjohn. This is the approach we are going to take. The Teensy is already housed in a carbon fiber box, with no ferromagnetic components other than what might be on the PCB (ie, nickel plated SMD's?). I am thinking that perhaps the 3T is erasing the flash memory of the Teensy and...

I have no experience with placing microcontrollers in an MRI. If you do, please offer suggestions. If you don't, then please don't provide advice on irrelevant topics like MRI safety. I am well aware of the possible effects of a 3T MR, and you don't just get access to such things as 3T MRI's...

Hi, I have a research project that involves placing a Teensy 3.1 in a 3 Tesla MRI. Unfortunately it seems that this does not work and the Teensy becomes unresponsive. I have no experience with such things, but does anyone know why the Teensy becomes unresponsive? I am curious if there are...

Thanks for looking into this. I'm still getting it to drop the connection occasionally, but perhaps this is related to me having a VMWare session running concurrently. I will shut it down and try again. The program will only print something if the bytes it's reading is different from what the...

Apologies, to run it: ./test_read 13824 4608 /dev/cu.usbmodemxxxxx 30 I have tried a few things (eg, closing the port after every read of 13864 bytes), and it seems to be much more stable now. I will keep trying to see if this is the still the case. I appreciate your time.

OS X 10.6.8. I should have mentioned that.

I am working on a project to transfer data from the Teensy 3.1 to a Mac via USB. I am sending a set of data (an array of 4608 - 32 bit integers) from the Teensy 3.1 to the Mac. I am sending the 32 bit integers (only 24 bits are important) as an array of bytes using serial.write(), and then...

I appreciate the help on this, Christoph. I am communicating with a sensor that send 24 bit words at 24MHz. I am not sure how the sensor will behave with a short gap between the 8 bit and 16 bit frames. So, aside from the elegance factor keeping the 24 bit frame together in one uniformly...

This seems to be working, although I will run it through some more tests. I found I had to add an #include <SPI.h> header. But no big deal. I am communicating with a device that uses 24 bit words, but since the ARM doesn't support words longer than 16 bits, I have to separate this into...

OK, so I guess it's not just me then. I am still having some issues. It's getting caught up in the while(trx.busy()); loop. I am trying to make 24 bit word transfers using SPI at 24 MHz, and was hoping DMA + SPI would help eliminate the gap in sending 8 bit + 16 bit words within one chip select...

Thanks. Yes, I am using the Arduino IDE. I have tried this revision, but I get the following error: I have added the following template declaration for ActiveChipSelectLow in ChipSelect.h: #ifndef CHIPSELECT_H #define CHIPSELECT_H #include <core_pins.h> /** A abstract class that...

I have been looking into DMA SPI transfers and came across your library. Unfortunately, when compiling the example code, I get the following error: Arduino: 1.0.6 + Td: 1.20-rc5 (Mac OS X), Board: "Teensy 3.1"...

That's a good point about VMWare. I run on a Mac natively (OS X 10.6.8), so I will shut down VMware and take another look. I appreciate your comments on this.

What's interesting is that it doesn't appear to show up anywhere on the USB bus. Admittedly, I haven't rebooted the machine yet to see if that helps. I am running VMWare, and when I choose to attach it to my Windows 7 VM, it shows up as an Input Device and the USB Prober now sees it. For some...

I have noticed the same problem on a Mac. The Teensy3 was working for some time and uploading programs, but then it suddenly got recognized as an Input Device rather then the Serial Network it used to get recognized as. I cannot upload programs to Teensy3 when it is set up as an Input Device...

I know the serial.readBytes() function has been optimized on the Teensy3 and is capable of > 1MBs. This is great, but I need to write data from the Teensy to a PC (Mac OS X) at similar speeds. Does the Teensy3 do this? Is there any reason to suspect that serial.write() would not be just as...