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It would be really nice if the flasher code could directly accept any .hex lines it is likely to receive.

I would study the example below. Look closely at how/where "client" is set.

https://gist.github.com/atomsfat/1813823

> A simple hardware diagnostic using patterns of red LED blinks is also planned

Nice! - black boxes are hard to debug. Would be very helpful to distinguish between "loader can't talk to MCU",...

That is my concern. Some protocols are likely to lose exactly an entire line. This could get flashed and the error might not be immediately obvious.

> you need to type in ":flash XXXX", where XXXX is the number of lines reported by the program

I recommend that you don't do this. Type in ":flash XXXX", where XXXX is the number of lines you...

For speaker analysis and correction, this is great.

https://www.roomeqwizard.com/

If you want to do convolution based correction, then just use the impulse response from REW and also use...

Yes, specifically "fast, partitioned convolution".

While it's only necessary for high resolution at low frequencies, I am able to run 12288 taps, stereo.

OK, I checked and some notes:

T4 with a small heat sink attached
It runs about 45C (far far different than the graph)
Slowing from 600 to 528 is only a couple of degrees cooler
wfi makes no...

In many cases, one could include this in their idle loop, which I understand reduces power/heat more than slowing down to 450 mhz.

asm volatile("wfi");

My guess is that at 450 mhz, it will last a very long time. And most applications won't notice the slower speed.

There was some discussion of strlcpy(). IMO, don't just use it, use it and check the return value. Ie:



if (strlcpy(dest, src, sizeof(dest)) > sizeof(dest))
handle_error();

3 years life at 600 mhz - that could be a problem.

Sure, you could pack four 10 bit samples into every five bytes. But consider other approaches - like a teensy 4.1 or a larger sd card.

My experience is that paste is better, even when you don't have a stencil. But I save time and frustration - unless JLCPCB puts most of the parts on, I always order a stencil. More advice - use a...

I agree with tomas. Is there a tool for predicting how many bits you need for how much distortion?

Consider either headphones (low bass with low power) or a subwoofer (which will need size and power).

For about $15, you can buy an external TOSLINK DAC box. Not the lowest cost option, but will probably outperform the PT8211.

Yes, it works on both 4.0 and 4.1.

See here for a newer, better teensy 3.x version:

https://forum.pjrc.com/threads/43165-Over-the-Air-firmware-updates-changes-for-flashing-Teensy-3-5-amp-3-6

Nice work Joe.

I use the audio library with USB input and SPDIF optical output. I have no noise issues.

You haven't explained what you need to do, but stay digital as much as possible and if you have to do a...

Nice!

Can you make a iMXRT1062 version too? :-)

For less noise, you should be doing a differential read on two analog inputs.

What options are available on a teensy to do bounds checking? Ie, what's the easiest way to find the above error?

IMO, the memory allocation details should be abstracted away for the typical use case. Ie, a single mallocX() call where you optionally pass it a hint as to the speed desired (or other...

I'd use the existing routine for writing blocks. Specifically:

void eeprom_write_block(const void *buf, void *addr, uint32_t len)

I'm curious, is there any reason that the library shouldn't have an empty constructor and do the initialization in begin()? In any case, just crashing is poor design.

My understanding is that if you omit the stop, then the bus isn't released and, with your slave chip/application, the following start isn't needed/tolerated.
But the libraries don't provide a way...

Good that you found something that works. As I see it, your application could use less buffer space if it had something like this for all but the first and last portions:
...

You should post your actual code. I don't know much about it, but possibly use wait_idle() between partial writes.

Can you do many smaller writes? What is the target chip and software running on it?

There is a nice spreadsheet coefficient calculator/visualizer here:

https://www.minidsp.com/applications/advanced-tools/advanced-biquad-programming

+1 on using the teensy code (see...

> The geometric mean gives 965Hz, i.e. 35Hz bellow the 1000Hz

I get:

sqrt(1390*720) = 1000.4 Hz

If you really need a custom iMXRT1062 design now, then I'd design it for both a MKL02 and a jtag connector.

>but not symmetrical around 1000Hz.

You should use the geometric mean and with that, it is symmetrical.

You might as well get used to the teensy way of debugging. Lots of print statements, sometimes with a Serial.flush() followed by a delay.

Two questions:

I use partitioned fast convolution to greatly reduce filtering delays. Can't partitioning be used for this application?

If one does use 96 biquad bandpass filters (which seems...

I only looked at it briefly, but that code appears to be doing a FFT and then combining bins. Not clear why so many people write code without comments.

Agreed, the typical person watching is likely to prefer larger bins and less delay. You can still use the same number of lights, probably most people won't notice the lack of accuracy on the low...

+1 on combining bins. Say you down sample to 11K sps, then run a 22,000 sample FFT. Each bin would represent .5 hz.

The DD4WH code is an example of large FFTs.

If one is going to mix digital circuitry with analog audio, better to use differential/balanced for the audio. Or stick with digital audio (eg, an i2s microphone).

Is the teensy loaded with code that emulates a serial port?

With com0com, you would just have to write the code to move bytes over TCP.

http://com0com.sourceforge.net/

Or possibly this:

https://tibbo.com/support/downloads/tdst.html

Very minor change - leave interrupts off when done flashing.

With interrupts, it's critical to be clear about during which stage. The first when data is being moved from input to upper flash and the second when upper flash is being moved down to lower...

The ESP-01 seems like a good fit.

I didn't look closely at what you are doing, but in general, for low jitter input, you can disable interrupts while waiting for the next pulse. Or use an interrupt of the highest priority to capture...

I would have some use for a teensy version of OpenLog that uses MTP over usb. But would have to have similarly low power consumption.

A fine but important point. When you use the teensy clock to measure a ratio between two external clocks, drift in the teensy clock is mostly irrelevant. Because it effects both measurements...