Someone made an interesting FPCB to access JTAG for Teensy 4.1:


It looks like it has to be for a Teensy 4.1 without Ethernet.

I'm sure Paul (pjrc) has read the threads that ask for JTAG access or a "development" Teensy with JTAG access.? Maybe, one day.....

Ian?

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Jack, W8TEE

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On 2023-09-20 15:12, Albert Peter wrote:

Having worked with most of the Arduino line and several other
microcontrollers, including the Blue Pill - the Teensy has a whole lot
going for it,

I was wondering if there would be any point to ditching the Teensy and just
using its CPU, the IMXRT1062. Not to save money, but to have less pins, less
board real estate. AND to have genuine JTAG debug. And there are better IDE's
out there...

One problem with that, is that the exact CPU in the Teensy is a BGA ( Ball Grid
Array ). I'm damned good at soldering, but that's where I draw the line.

- Jerry, KF6VB

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Having worked with most of the Arduino line and several other microcontrollers, including the Blue Pill - the Teensy has a whole lot going for it, especially
for demanding applications like SDR. Some of the Blue pill brothers have the raw power, but the question is do they have the wide library support that Teensy has? There is also the question of a suitable higher res screen. You need at least the 800x480 pix to show what the T41 has. On the grand scale of things, you would not be saving much if you do want performance. - Note that even RASPI is much more expensive that Teensy 4,1.

A primary requirement of the T41 Sw is support for the ARM DSP library. Other micros do support it, but that is a basic need. Doing a port of T41 SW to the STM32 family would be a pretty large task, IMHO.

Just my 2 cents worth.
Al
AC8GY

All:

I'm still plugging away on writing the assembly manual and building the T41 kit from 4SQRP. I was able to get the receiver done today and was listening to CW on 15M today and took a few seconds of video. It shows the T41's ALP decoder in action. This is at about 34WPM. The interesting thing to note, however, is how an adjacent signal (perhaps 100 Hz away) does not affect the decoder. You can see the video here:



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Jack, W8TEE

Thanks Jack

No,I think they were small changes.? It's a while ago.? I'll check and get back to you.

I remember being quite surprised what good time it kept.

Harry? GM3RVL

The system described in the article uses an Si5340D, which can provide "complementary clocks" (180 degree) from a single programmed output.
That sounds exactly what you are proposing to do with the Si5351.? I have both the online and hard copy of the article.? I can send you the hardcopy
when I return home next week.? It's a very interesting article.

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73 Greg KF5N

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Jack, W8TEE

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Ive seen most of the other radio groups clammering about adding a real time clock module to their radios of late. ?I suspect, long term, this is the teal answer. ?

Jack and Paul

I have a modified version of the direct frequency entry software which allows you to set time and date.? I tried it out on a couple of? 'volunteers' and they identified a few issues which I've not had time to sort out yet.

Would that be helpful assuming I can sort out the issues they raised?

Harry GM3RVL

Hi Greg
I've just about finished the RX board and the wiring from the main board with the 2 clocks.? Be interesting to see how the RX works with the divide by 2.
I Googled QEX.? It is an ARRL publication.? I must try to find the article you mentioned.? I'd be interested to know how it dealt with keeping a fixed relationship between the two div by 2s.
Harry? GM3RVL

Thanks Jack, that's just what I needed know.

Paul, KI7LW

It has been a few years since I took it, but it was top notch instruction.? Also very unique, since the data being analyzed is music.? A refreshing change from the usual dry engineering material.
I had better understanding of the DFT and data sampling than from any other source I had studied before.

--
73 Greg KF5N

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Jack, W8TEE

Thanks for the link. It looks like a useful course.

I'm curious as I started a Coursera course a couple of years ago. I won't say which university it was through, but I'm pretty sure it was in Colorado. It was on sensors and motors as in process control, and it was much more detailed than I expected. I'm not exactly a rookie, but it was going to take a lot of study. I reported some problems with equations being wrong (units didn't work out, etc.) and I got no response from the instructors. Several other students reported that quizes had some wrong answers and also got no resposne. I dropped out due to lack of instructor support.

How was your experience with this course?

A review of the code seems to imply the T41 time shown in the display should sync up with the DCF77 time signal, but I've never seen that happen (I live in Phoenix). Should it? If so, is there a way to have it sync up with WWVB, which is more accessible in my part of the country? I couldn't find any messages on this topic and haven't seen anything in the book (first edition), hence my question. I have a GPS module I could use to do it but wanted to ask the group first before I move in that direction.

Thanks,

Paul (KI7LW)

Not a book, but an online course:



There are lots of exercises using Python.? This is one of my favorite technical courses.? I didn't take it for credit, only for learning.
This course covers the fundamental basis of DSP.

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73 Greg KF5N

Thanks for the advice guys.? You make a convincing argument for the Teensy, so I'll be sticking between the lines on that one.

As an analogue transceiver builder, I'm really looking forward to learning something new.? Also, I'm enjoying reading "Digital Signal Processing A Practical Guide for Engineers and Scientists" by Smith as an accompaniment to your book.? Since I'm in the Lit / Research phase of the project, I might ask if you had any personal recommendations of books that offer intuitive insights into DSP (although it's hard to beat Smith in that regard!)

But perhaps that's the subject of another thread.
P.S. the book has just arrived.? It's going to be a long night!
73