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OK, I am guessing the constructor doesn't use the USBHost parameter, but the constructor is defined this way to force the caller to have already created a USBHost object as a safeguard?

OK, I think the USBHIDInput override for operator bool() is responsible for the driver claiming boolean: class USBHIDInput { public: operator bool() { return (mydevice != nullptr); } https://github.com/PaulStoffregen/USBHost_t36/blob/master/USBHost_t36.h#L523

I am trying to understand the general architecture of the HID device drivers in the USBHost_t36 library. I didn't find any overview docs on the library, so I am researching it from the code. Specifically, I don't understand how the relationship between different objects is established, like...

MIDI uses a current loop. I think you need to tap off the Thru signal after the opto-isolator.

It should be located above: https://forum.pjrc.com/threads/54345-ILI9341_t3-font-editor?p=191271&viewfull=1#post191271

Sounds good! The LVGL font spec is here: https://github.com/lvgl/lv_font_conv/blob/master/doc/font_spec.md

Thanks for this! It would be awesome if this also supported the LVGL font format ( https://lvgl.io/tools/fontconverter ) or an intermediate format to work with the existing LVGL converter.

I am using a custom board (with FlexIO2), but it looks like the standard T4.1 should have enough exposed consecutive pins on FlexIO3 starting with AD_B1_00 for the 16bit bus, plus 4 pins for D/C, WR, and CS. The example I started with is here: https://community.nxp.com/thread/501529 But using...

I have used the FlexIO with 16bit parallel interface, based on the mculcd demo from the NXP SDK. It works well, although I did have to tweak it a bit.

I had good luck with umm_malloc: https://github.com/rhempel/umm_malloc

OK, I have gotten somewhat further. I was able to get ThorsSerializer working with SdFat (Teensy4 beta, using SDIO) for serialization at least. I had to change SdFat to use custom class names so that it didn't conflict with stdlib, and then adapt ThorsSerializer to use the SdFat streams...

Yes, that is definitely an option. My member types are fairly simple, ints, pointers and vectors, so a library is maybe a bit of overkill in most cases. But I wanted to check for recommendations before I go too far down that rabbit hole. By the time I handle the various data types and the...

Thanks Paul. I am trying to accomplish the serialization of a large amount of application data (MIDI) from an external RAM chip onto an SD card for long term storage and data exchange. Preferably in a human readable/portable format, like JSON. The external RAM is larger than the RAM banks in...

I have been researching on the best way to serialize large objects for storage on the SD card of Teensy 4. Specifically ones that don't have to store a DOM into a temporary variable, before serialization. I have tried Boost, Cereal, ArduinoJson and ThorsSerializer. I think for my purposes...

Is there a recommended approach to use SdFat along with existing newlib stdio functions? I was able to get SdFat to work by renaming all of the classes and members to something other than the stdio equivalents, but this creates other problems for classes using stdio types...

I have been banging my head on this for days, especially since I would have thought it would be a common question! I'm trying to serialize some objects to store them onto the SD card in a Teensy4. My project is *not* using SD.h/SdFat because we are using a different toolchain (SdFat collides...

OK, Thanks for confirming. It looks like the linker file needs to have modifications to include the code for the flash memory drivers of the EVKB

Were you able to get an Arduino built .hex file to load into the EVK? I am trying to use a J-Link to flash the EVK with an Arduino hex file, it looks successful, but does not execute successfully. I am trying both a simple UART (using LPUART1/Serial6 for the UART/USB bridge) or LED blink...

Here's the TB-3: Device VendorID/ProductID: 0x0582/0x017B (Roland Corporation) I can get my T3.6 fired up with the host implementation and put the analyzer on it when there is a test build for this combo.

I took some quick Beagle captures of MIDI incoming from the TB-3, it looks like pretty standard USB MIDI, although there is a second message following the standard message (for NOTE ON/OFF at least).

I have a Beagle USB protocol analyzer and Roland TB-3, TR-8, MX-1 (no VT-3 unfortunately) if it may help to identify if one of the vendor specific interfaces uses standard USB MIDI packets in some way...

I believe the Roland devices use proprietary drivers (they aren't class compliant) so you won't be able to use them with this host implementation

I am also looking at USB HOST MIDI implementation and would love to build out *sending* MIDI (it currently only receives MIDI input). I couldn't find any of the USB HOST device drivers that send data out... to get an idea of how to actually send data back out using the USB host port. Is there...

Thanks for the comments. My previous experience for "displays" is with 7-segment LEDs, which are obviously much simpler. I guess I'm not sure about how the underlying graphical assets are generated/displayed on a graphic display like that. Things like rounded tabs, fonts, icons, etc. Do they...

This may be a fundamental or "it depends" type question, but I haven't found any guidelines or benchmarking for the topic. I am thinking about using a graphic display in my next project, something like a 128x32 graphic OLED display. Basic use of the display is no problem, but I wondered how...

Is there a standard way to handle power down on the Teensy/ARM? What I mean by that is the user will usually cut power immediately with a switch, if you don't have some type of "soft power button". When this happens, in my case, I get some small amount of garbage/incomplete data sent on the...

Yes, there are situations that arise where the teensy can't be reprogrammed without pressing the button... See my previous thread about windows: https://forum.pjrc.com/threads/31912-Windows-7-%2864bit%29-standlone-teensy-loader-stalls-during-upload-sometimes This situation was totally...

I am still getting quite a few user reports around this error. I think it may be related to the fact that the user is using the loader for the first time, and using a key combo to start the bootloader (using _reboot_Teensyduino_(); not the hardware reset button). Could it be that the loader...

Thanks Paul, I use NetBeans and a makefile directly with Teensy loader and the files from an (older) Teensyduino install. If you have a memory of where/what the fix was, it would help, I will try and dissect a newer install in the meantime. EDIT: I see the other threads on the El Capitan fix...

I have a report from a user with a similar situation (USB-MIDI, Teensy 3.1 on Mac OS X El Capitan 10.11.2) I had them trace the USB enumeration using USB Prober and the device is not enumerated correctly, it is missing endpoints and some values are incorrect. The same device is working on an...

OK, I created a Win7 64 bit VM for testing and it works every time... In the meantime I had a few more customers get the same failure on Win7, so I will try and get a physical Win7 box built. The VM USB layer may be masking the problem.

Thanks Paul, I need to see if I can actually recreate the issue using my board... I don't have immediate access to a Win 7 machine. If I can find a Win7 box I hope to gather more information and try it on a PJRC Teensy also Is there any difference between using the reboot function and the...

Hey all, I have a product that uses the teensy 3.1 bootloader chip on a custom board. My customers are instructed to download the teensy loader app when it is necessary to upgrade the product. I have had quite a few customers running into an issue when performing an upgrade on Windows 7...

Well, I did the "sensible" thing and disabled DSE in the pinMode function for everything. I'm not driving any major loads with my output pins, so hopefully it should not be a problem. Now my noise problem is obsolete, thanks for the help everyone. JK

Wow, even better! thanks! I turned off the drive strength for SCK and MOSI and get a considerable noise improvement. I see that PORT_PCR_DSE is being set for any pins designated as output in the pinMode function, how can I determine if/when drive strength is needed on a particular pin? JK

Hmm, thanks for the tips... I was able to get some major improvement by adding even more decoupling 100nF caps on a relatively long trace for the rails and SPI bus. Putting a 20MHz bandwidth limit on the scope and using a shorter ground connection also cleaned up the measurements. I am using...

I am probing the output of my Teensy 3.1 board which is driving driving some SPI peripherals... Everything works as expected, but I do see some very high frequency noise on the power rails, which is related to the SPI bus whenever SCK is transitioned. The noise is about 100mV spikes in the 5nS...

Do you happen to have an example of the per-project makefile for NetBeans with Teensy 3.1? In the example are a lot of relative paths, which don't match up with my NetBeans paths. This is just to compile a very basic test main.cpp. gcc throws an error with some of the options picked up in...

Something like this may be a good candidate: Thanks JK

Thanks for the suggestions. The isolator I'm using is the ADuM 3160 on the PCB, so a cable adapter would need to be sourced with bare leads on one end. Similar to this, but for micro USB (expensive): http://www.argentdata.com/catalog/product_info.php?products_id=111 I don't need USB power for...

Hello, I am considering using Teensy 3.1 inside of a (small scale) commercial product. This seems to make sense in terms of time and cost for a short run product. The one major hurdle I need to resolve is breaking out the USB connection. I plan to have a USB isolator chip and a separate PCB...