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Hey All, Is there library support for dual USB on Teensy 4.0, where both USB ports are in device mode? I want to connect it to two PCs and accept commands from both.

Thanks Paul, so erasing it would be the safest solution? I'm about to port a longer term project from FRDM-K64F to teensy 3.5 but need to retain proper debug capability. Just don't want to blow anything up.

Quick question on this subject (to Paul, hopefully). I understand that the longer term plan for the Teensy bootloader is that holding the DE pin low would tell the bootloader to leave DC and DD alone for an external debugger's use. Does the current bootloader take immediate control of those...

Oh, forgot to add. Have a look on youtube for videos on soldering surface mount components. There are some good tips on there.

Just asking here, but why go to the trouble of desoldering the components rather than just purchase new ones? It seems like a lot of trouble/expense. Especially a BGA part. I had a local company replace a BGA for me a year or so ago, it took them a week and cost £60. I don't think it would have...

I'm afraid I can't answer as to what the Sumotoy library supports. I've not used it myself. Hopefully some else can chip in on that. Hopefully also someone might know whether that lib needs MISO. Perhaps you can give a bit more detail of your project? It's not clear to me that you have a...

Re the RA8875: Are you planning to use a library or write your own code? The MISO pin is used for reading status register also, not just data. If you're writing your own code, you could probably get away without using it (albeit maybe not with the most optimum performance but OK for most...

Yes, there are two levels of interrupts on these cores, but being honest, your question doesn't make much sense. Can you tell us more about what you're trying to do?

Yeah, I guess you probably can. You'll only need a SWD/JTAG tool if you want to do single step debugging.

There's a difference between 'driven' high and 'pulled' high. Think of it like this; Driven is as good as connecting it directly to the power supply, whereas pulling it high goes through a resistor to the power supply. When CS is asserted low, it is 'driven' low. This is as good as being...

You bacially have 5v on one rail and 3v3 on another which are connected via two series resistors. So current will flow through the resistors, that is true. You can work it out with ohms law. 1.7v divded by the sum of the two pull-up reststors.

It doesn't like __PRGMTAG_ in the LCARSLARGE.h header file. If you cant/dont want to change that header file, insert the following line somewhere before #include "fonts/LCARSLARGE.h" #define __PRGMTAG_ e.g. the top of your file might be. #define __PRGMTAG_ /* define this as nothing, to...

In the Flextimer section of the manual, look up "Complementary mode".

FlightSimCommand NavCoarseUp; FlightSimCommand NavCoarseDown; FlightSimCommand NavFineUp; FlightSimInteger NavFrequencyHz; These lines look like they are declaring variables of FlightSimCommand and FlightSimInteger types, but you haven't told the compiler what those types are. I suspect you...

Do you have a link to the post you read? If that is true, the only reason I can think of would be if the Audio board library is coded that way. Are you using the library? Maybe someone who is familar with it can comment?

Yes, of course. As long as it has a different I2C address.

Use an array. E.g. const int num_leds[] = { 61, 86, 94, 86, 61, 94 /* if you want to add another strip, just put its number of LEDS here */ };

Crossworks for Arm will do exactly what you want. It's a very easy to use IDE that uses the GNU compiler, and I'm pretty sure is free up to a certain code size limit. A bare minimum Kinetis project will give you just enough code to setup some default interrupt vectors, boot and clear out...

I think Detriot_Aristo has probably hit the nail on the head, but check the baud rates are the same on both sides also.

How many displays do you want to use? Are you considering shift registers to save pins?

The crash wont be because you're comparing different data types (although ideally you should cast those ints to unsigned char for the test), the crash will be because you are dereferencing header, which probably is an invalid address, or a peripheral that hasn't had its clock switched on. Where...

As I say, I'm not familiar with the workings of the libraries as I dont use them, but my guess would be that they are hardcoded to use certain pins. I think if you are using two or more libraries that conflict over some pins, you would expect to see odd effects. E.g. if the audio library takes...

If you have no data sheet for the part, I'd say rule of thumb, go for 10mA across an LED. Maybe slightly more, 15mA maybe, but not much more than that for an unknown device. On a micro pin, I think the max is 25mA per pin. Not sure what the max for the whole device all at once is. How many of...

Ok, so I don't think you have to worry about the MISO issue that you've found. That would only be a problem if you want to read from two SPI devices, if one of them is RA8875. From what you've said, you only have one device using SPI, the RA8875. I think the problem you haven't perhaps...

No. Personally I wouldn't advise the later solution. I'm not familiar with the exact display it talks about, but it sounds like there is a good chance of damaging it. What are you using for your audio? and what do you want to do with audio exactly? receive audio samples or just send them?

So I guess you want the LED to light when the button is pressed? I'd put a resistor in to protect that LED, That's waiting to pop without one. And go for the 3v3 so you know for sure what voltage you're using. I'm guessing you're powering from USB, so your Vin is around 5v. Of course, Vin is...

Just a suggestion, but k64f has two USB modules, it might be easier to have one as permanent host and one as permanent device. That way you could fit dedicated USB sockets for the two different modes, (e.g. A for host, B mini or micro for device) rather than swap cable assemblies around. Your...

Pretty sure the chip supports two USB channels. Only one of them is high speed though. I assume you mean you want to be USB host to two devices? Really not sure what you mean by 4in 4out??

I have used RA8875, and you've pretty much summed it up. Those are limitations of the chip. Not criticising RAIO at all. When you think about how much ROM it would take to support more than just the four Latin character codes, and then with different fonts. That is a colossal amount of ROM...

Quick question. On the DIP64 version, I can't find were reset_b is broken out to. Is it broken out? Is there a schematic?

enums are used to assign values (typically unique values, although you can force specific values if you wish) to meaningful names that make your code easier to understand. They can be a data type of their own if you declare one as a variable, but they don't have to be. For example, if you...

That's definitely the obvious and easiest solution. If you're short of pins, you could use a resistive ladder into one analog input. Requires a few external resistors though. With a restive ladder, you can comfortably go up to about 9 to 10 switches, still using only one pin on the micro.

No, I don't think you're missing anything. It looks fine to do it that way. As you say, you would get much more efficient use of I2C. The only trade off is the ever so slightly more complicated unpacking of the data. I guess that is why the library writers do it the way they do. Providing a...

I was thinking more the power supply rails being a problem than the data lines. It would be nice to see a mock up schematic for those though I suppose. As GremlinWrangler says, a common solution is to connect each power source through a diode, so there is no way for one to feedback into the...

No. Be careful with that. Tying grounds together might be ok, but not the supply voltages directly. That could easily lead to damage to the computers or Teensys or burned out wires. Fire hazard either way.

No, don't know of anything specific like that. Would suggest googling it. What I suggested would be easy to set up if its just for you, but if you want users to be able to create accounts, that is much more work. There are load of freebie website that will do that, I'm sure, but in my...

Just so I understand you correctly, the Teensy is the client? and you want it to be able to send data to a web server somewhere from Teensy? How much data, and how frequent? If its a small amount of data, relatively infrequently you could write your own in PHP (provided your Apache server has...

I think the biggest determining factor as to whether to use an RTOS is 'is there some existing code written for that OS that you plan to use?'. E.g. if you already have OSC/MIDI source code, or a display driver for a specific display that you want to reuse, either of which that relies on APIs to...

Firstly, yes, I think you can do what you want with a Teensy 3.5 or 3.6. I think maybe you're right about not having enough consecutively numbered pins available on the 3.1. Secondly, for a model railway, I really don't think you need to. You're asking for the ability to do atomic writes to 8...

You should be able to use multiple SPI modules at the same time. There is very little information about your project for anyone to guess what might be going wrong for you. Maybe tell us a few more details, e.g. what Teensy you're using? a schematic maybe (or at least a description of what pins...

Just looks to me that you need a function prototype or definition of synthCalc before you use it. So either put the following line above the setup function void synthCalc (void); or put the synthCalc function before the setup function. The only thing that's puzzling is that you say it...

You could look at flexbus as option to expand memory-mapped RAM. I've not seen any working examples though, anywhere, of suitable parts or reference designs. It looks quite pin consuming also.

LPC-Link2 programmed with CMSIS-DAP firmware works with the Kinetis chipset, I can confirm that. It should work with any modern ARM core. I don't have a ST-LinkV2, so cannot say. Is it CMSIS-DAP or some ST proprietary thing? I ordered a couple of Loglow's breakout boards yesterday as I want...

Good on you, I say. It’s nice to see a newbie to embedded software who wants to get their hand dirty at the low level. Anyone can get projects working using someone else’s libraries when all the hard stuff is done for you, but are they really learning the skills that are unique to embedded...

1ms polling seems a bit overkill for the keypad. I'd recommend doing a sweep every 10ms, and the debouncing is that you want four consecutive matching readings to determine whether a key is pressed, or released. For the rotary encoders, these are better done using interrupts. Polling is never a...

From what you've said so far, personally I'd be looking at either I2C or CAN. Would need to know more about the project to weigh up the pros and cons though. In any case you do need to think about addressing. I.e. how will you assign addresses for the different modules/information packets.

I cant see any practical problems with what you're planning. Even with all the switches pressed, I'm sure you wont be drawing enough current to cause any issues. Just a couple of random comments. I guess you will rely on internal pull-ups, as you don't seem to have any external ones. If the...

Are you really interested in how they work, or just trying to get a project up and running with one?

Sorry for the slow response, broke my laptop :( I think. 1. 3v3 2. DD 3. GND 4. DC 5. GND 6. NC (I don't think we can get to the SDO pin on the main micro) 7. NC, but can be cut off with side cutters. 8. NC 9. GND 10. Reset to the main micro (not DE) As I said earlier, for DE, I'd put a...

Not quite. If you're using I2S you can have two stereo inputs (or four mono inputs) at the same rate. There is only one master clock signal that clocks in both inputs together. The slower data rate was only in reference to WXMZ's suggestion to use TDM and "daisy chain" devices together. That...