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Was an AMScope unit with two eyepieces and a port for a camera. Not in low budget territory, but has proven it's worth many times over. Have it permanently at my desk. I just slide the head into position when I need to take a look at things. Someday I'll get a camera for it, but haven't seen...

A while back, I bought a stereo microscope for soldering and fine work. It works great and has enough offset from the work to get a soldering iron into where it needs to go. I had to install a Barlow lens to do that. It even has a camera port on it, but I've yet to install a camera. Haven't...

Teensy 4.x I/O are NOT 5V tolerant. Use a buffer. Max input voltage is VDD+0.3V, which is typically 3.6V.

A 1N4148 diode is about 3nA @5V reverse bias. Less at lower bias. The leakage does double every 10C. So operating at 70C, the leakage is 32x greater than at 20C. However, the impedance of the input pin matters. If it is 1Meg or less, then the voltage on the pin is under 0.1V, even at...

Been stalled. Vacations, travel, grandchildren, life, etc. Have made no progress on this. Need to get back to it. The development work isn't easy for me. (I'm out of practice.) My development area is a mess and it's not trivial to straighten it out. Thanks for inquiring! It gives me...

Not a very kind response. Just relaying my hard won experience. BSEE 1978, MSEE 1987. Your mileage may vary.

Personally, I wouldn't do that. Diodes conduct in both directions, but they are obviously asymmetric. One learns this when creating diode stacks for high voltage applications. So the Teensy pin will be subjected to 5V. The question is how much leakage current at 5V can it take? I'm not...

If it's the other way, doesn't the Teensy see the 5V and die? I don't understand the circuit then.

That's technically only 1 diode drop, or 0.7V. That's not enough of a drop from 5V. Could damage the Teensy pin. 5-0.7 = 4.3V. Two diodes would be a drop of 1.4V. 5-1.4 = 3.6V, which is at the absolute maximum of the part. (3.3VDD + 0.3V) Not safe (for the Teensy) either. However, I...

I can't vouch for your code. But lockable Teensy's do what you want. They can only be programmed by builds using your key. They cannot be loaded with any other code once locked, only your authorized code. Search for this on the PJRC website.

Short answer: Something is taking too long. Now to find it. Think I have a better handle on logging now, with the structs. May go back to my original idea of attempting to profile parts of the code. I can time each function in cycles using ARM_DWT_CYCCNT (modifying for rollover later) and...

I didn't need to with the SW encoder. Luni had extended it to 64 bits for EncoderTool. The 64bit rollover is so far out, I didn't need to deal with it. (3.89 million years @ 2200 RPM!) In [19]: 60/(2200*4096) *2**64 /3600/24/365.25 Out[19]: 3892103.4674003003 But the HW encoder is only 32 bits.

Not so fast on the revolutions... The lathe can operate up to 2200 RPM, this is needed for small diameter pieces, to get the surface feet per minute up to the recommended cutting rate. So for feeding (not threading) the WRAP will occur in 7.94 hours. I need a way to handle this event. Other...

So does this means a priority 16 is handled the same as 17? Or if 16 comes along it will interrupt 17? UNTIL THEY WRAP... then what happens? I need that to work as well. That's the crux of the problem. That could happen if the machine is left on for 8 hours. I want to avoid bad stuff...

Can I have PIT timers with different priorities? PIT1>PIT2? I want to ensure my Bresenham algorithm works for both positive and negative directions. I can post that in a following note. The lathe can run either CW or CCW depending on what operation, or what handed thread is cut, RH or LH...

I spent the past couple of hours marking up code and getting an assessment of what I need to do. Have a couple of questions on various topics. 1. Whats the max duration of IntervalTimer? Does it pick the appropriate timer according to the delay? 2. For prioritizing timers, is it possible to...

Your method is simpler and easier to understand (for me). I rarely use pointers, unless I really have to, because I know I make pointer errors!

I don't understand this. Isn't the max PTR value = 0x70000000 + sizeof(PSRAM) - sizeof(fooData) ? maxPTR should be the address of the last struct in PSRAM, correct?

Originally I was doing this all at 400 RPM to stress things. That was the ~36us. I don't know what a DWORD is. C and microprocessors are extremely inconsistent. The micro guys are always redefining terms. What is a DWORD? What is sizeof(DWORD) for a Teensy4.x? 4 bytes? That's why I used...

Since you are sampling at twice the rate (due to the 400 RPM vs 200 RPM of my test) you can only have 4 uint32_t's in your struct. What you have is consistent with my calculations. Thanks. This is going to be one heck of a hack-a-thon.

Thanks for the explanation. I need to figure out how to trigger this intelligently, as there's not a lot of spare memory. A simple way for me is to start when I touch the start button. But after the start, I have to physically engage the half nut lever, and that can take a random amount of...

Got down to the shop. After setting up, which took 10 minutes, the actual threading pass I timed at 7.5 seconds. That was setting the cutter 2.5mm before the work piece, and cutting 4 threads at 10 TPI. This includes fumbling to sync the lead screw. I can't imagine being faster than this, 10...

So I understand the output, in an ideal situation, the index value should be what every time? Index at every 200 ms? And one would expect a plus minus 1 count from the average difference?

I will check how long a time interval I need, perhaps I'm overestimating it. Will time it this morning. Parts of the process are manual, which can be variable. Synchronization with the lead screw is discrete, and there's a human (me) in the loop. Worst case, I'll have to double the PSRAM to...

That's reasonable. I have to start somewhere. Tomorrow morning will strap on the noise cancelling head phones and have a go at it! No matter what, I'm sure there will be some interesting finds.

I understand. Just suffering from some analysis paralysis. Not really sure what I need. So I'll try something and dare to be wrong. Need to go to the lathe with a stop watch or something like that and time how long a test is. It's been a while since I've been in the shop. N will basically...

Maybe. First glance, yes, but you know how it is. I may just want it to stop, so I can see what happened up to that point. I mean if the address counter is at the end, I can just stop, correct? I don't want rollover to wipe out the initial conditions... Very interesting! I find these...

Re: post #197. Actually, I was not being inconsistent. I don't need many rotations (threads) after the first contact. Just enough to establish phase information. What I do need to capture is what is happening before contact AND the few threads after cutting. At the moment, the start logging...

I strongly recommend using some sort of driver board. A Teensy 4.1 cannot directly drive a stepper motor. Also, many stepper motors take voltages that will destroy a Teensy 4.x. I use an opto-coupled stepper driver so that there's no chance of harming my Teensy. To drive the opto-coupler I...

It's hard to control computers, press buttons and actuate lathes at the same time. If I'm out of sequence I don't collect the data, or the buffer fills, or machinery breaks, the work piece is ruined or I get injured. None of those things are really appealing, especially the latter items...

I have 8MB of PSRAM. I'll rerun my calculations on how much I can save. Two rotations is not enough time to log, probably need the equivalent of maybe 10-12 seconds, maybe more. That's like 80 revolutions, or 327680 interrupts (@ 400 RPM). So I need to save at most 24 bytes per edge, or I'll...

Where do you do the sprintf function? In the ISR? Then copy the resultant string to RingBuf? Then in the main loop after the excitement is over, you spool it out?

I was on vacation for a while. (Still am.) Can you explain the syntax of the EXTMEM line? EXTMEM logRecord logRecords[NUM_RECORDS]; logRecord is a struct, logRecords is an array of struct? And the array has 8192 elements (structs)? You dump the data in the main loop with some sort of command?

If one uses setClipRect is that what DMA uses as the buffer? I'm kind of unclear on how to use DMA with the ILI9341.

Thanks. Generally, the issue with stuff like this are drivers. Did a brief look earlier and didn't see a driver for a Mac. But maybe I didn't look hard enough. Will look again, because having the ability to do logic analysis is a good thing. Although, @h4yn0nnym0u5e pointed out to me the...

It's overkill for your application, but CAN is message based, so abstracting away the bus stuff, it's like Serial. You can have simple commands, like just a character. "F" for off, and "N" for on, for instance. Or whatever. CAN is far more sophisticated than that, but you don't need the...

How close of a synchronization is required? To nanoseconds, microseconds, milliseconds or seconds? If roughly milliseconds, I'd use CAN, and twisted pair between Teensies. You need a 3.3V CAN transceiver. A differential signal is good for longer wire runs as it's more immune to noise...

It was used for a DC measurement, was charging a laser pulse capacitor. Used a lot of resistors in series to minimize capacitance. Did the job that was required. Measuring HV transients isn't that easy, due to the isolation requirement. Measuring the ionization current sounds easier to me...

Interesting article. In that circuit the ground of the plug is technically not at ground. In a real engine the threaded section is grounded, since the block is ground. I'd isolate the case from the plug, but that's me. Been shocked more times than I'd like to admit. The circuit shown can...

Some people are using the spark plug ionization current. There's a lot of papers on the subject. Properly interpreting the current tells you a lot.

Having made a 50KV resistor divider, which needed to be in oil, I'm aware of the issues. You need 100's of megohms and ways to avoid creep and corona. Not to mention HV insulators. Solving the whole problem is obviously better, but 1/2 a loaf is better than nothing. I seem to recall that...

How about running the test on the primary side? Could you measure the voltage on the capacitors prior to discharge? If the caps are the predominant problem, might this help? The primary side is at a lower voltage, which could make the electronics easier. I understand that what counts is at...

Some crud that needed a second reboot? 2nd boot seemed to restore TyCommander again. It's working again. Edit: My code isn't working right, but TyCommander is functional again.

Thanks. So noted. Kind of lazy on that. Your way is much better. Will go through code and try to scrub it. No I didn't mean instantiation, my mistake. Sometimes (due to ignorance) use the wrong terms.

Well foo. TyCommander isn't seeing my 3 boards any more after an update to MacOS 15.6. I did the upgrade last night. Can't debug, as I need connection to at least 2 of them. Made the program changes, but can't get any serial data to display, dag nab it. Even put in @joepasquariello 's cycle...

I think I found something. I set the interrupt priority after the encoder instantiation. It should be before, if it's working as I think the code does. That assumes that the code does get the priority and at the moment, that's not settled. So I can try that. EncoderTool, TeensyTimerTool...

What makes this tough is the use of Arduino/Teensy libraries. It's hard to tell if there's some hidden global disabling of interrupts lurking somewhere. Like deep down in SPI, or something like that. I don't know how to confirm or deny if this is happening in my compiled code base. What's...

Sometimes 8us, have captured over 33us on my scope using persistence. It varies from ~2:1 to 50:1 ball park figures. I need to look it up. I thought about using position match, seemed like a bit of overhead, but it seems like it could be used. I'll check where I set nvic priority, don't...

Just had another thought. In EncoderTool, does the on change callback inherit the priority of the pin interrupt? If it's only priority 128, then it gets interrupted by everything else. Every once in a while I see a long duration ISR and I don't know why. I set the pin interrupts to be 32. I...

Thanks. I'm moving on to QuadEncoder, or some routine like that. Saw enough variation in EncoderTool counts to convince me there's a problem with it. It's weird, it seemed awesome in the beginning, but there's apparently some kind of issue since the count is varying for something that should...