teensy 4.0


VE2DX
 

quite obvious that teensy 3.2 is a major issue! for what I can ready here!

I saw Teensy LC and Teensy 4.0, LC looks like totally different hardware format, what about 4.0 can it be used to replace directly a 3.2?
--

73

Richard VE2DX
WWW.VE2DX.COM


pa2pim@...
 

The form factor of the Teensy 4.0 might be the same but it's also considerable faster.

I've used a Teensy 3.5 and implemented lot's and lot's of hard- and software changes.

One of the myriad of things I ran and run into is that some libraries can't deal with the higher execution speed.
Most noticeably now it's the interface with the LCD.
With a Teensy 3.5 @ 120 MHz the info on the LCD get's garbled at times.
The workaround so far has been to set a 48 MHz clock in the Arduino IDE instead of the default 120 MHz clock.
I've not stuck an oscilloscope in that part yet since the workaround is fine for the moment.

On a LoRa project I had a similar issue with the higher clock speed of the Teensy with the SPI interface of the Teensy 3.5
It was diagnosed that the Device select line was deselecting the device before the data transfer was done, see https://forum.pjrc.com/attachment.php?attachmentid=10948&d=1499109224  

I'm currently also using the I2C/TWI lines.  So far I've not seen issues with using that, at least not with the Si5351 signal generator chip controlled by the Teensy.

Next is the issue of signal levels. The Teensy 3.2 can handle 5V signals, the 4.0 can not, see https://www.pjrc.com/teensy/techspecs.html
The encoder and most of the other peripheral hardware are powered with 5V.

Now it's certainly doable to run some of them on 3.3V and/or use level converters.
Despite that the Teensy 3.5 I use can also handle 5V on it's IO pin's, that's what I did and it works fine.

So can a teensy 4 be used?

Probably yes but be prepared for some hard- and sfwr tweaking.
If you go that route have a look at the 4.1 first, same voltage level issue but lots more IO pin's which comes in very handy.

73 Pim , PA2PIM


Robbert J. van Herksen
 

Hi Pim,

Hete is another Loftur ML Controller lover, Robbert TA2/PA3BK living (it up) in Istanbul.

Your display is already slow when running the original Teensy 3.5, and gets really unusable at even higher clockspeeds.

The solution:

Get this OLED based display:
(It’s really fast, and very crisp)


Worked for me!

873 de Robbert




 XS Max (512Gb)

On 6 Oct 2022, at 17:16, pa2pim@... wrote:

The form factor of the Teensy 4.0 might be the same but it's also considerable faster.

I've used a Teensy 3.5 and implemented lot's and lot's of hard- and software changes.

One of the myriad of things I ran and run into is that some libraries can't deal with the higher execution speed.
Most noticeably now it's the interface with the LCD.
With a Teensy 3.5 @ 120 MHz the info on the LCD get's garbled at times.
The workaround so far has been to set a 48 MHz clock in the Arduino IDE instead of the default 120 MHz clock.
I've not stuck an oscilloscope in that part yet since the workaround is fine for the moment.

On a LoRa project I had a similar issue with the higher clock speed of the Teensy with the SPI interface of the Teensy 3.5
It was diagnosed that the Device select line was deselecting the device before the data transfer was done, see https://forum.pjrc.com/attachment.php?attachmentid=10948&d=1499109224  

I'm currently also using the I2C/TWI lines.  So far I've not seen issues with using that, at least not with the Si5351 signal generator chip controlled by the Teensy.

Next is the issue of signal levels. The Teensy 3.2 can handle 5V signals, the 4.0 can not, see https://www.pjrc.com/teensy/techspecs.html
The encoder and most of the other peripheral hardware are powered with 5V.

Now it's certainly doable to run some of them on 3.3V and/or use level converters.
Despite that the Teensy 3.5 I use can also handle 5V on it's IO pin's, that's what I did and it works fine.

So can a teensy 4 be used?

Probably yes but be prepared for some hard- and sfwr tweaking.
If you go that route have a look at the 4.1 first, same voltage level issue but lots more IO pin's which comes in very handy.

73 Pim , PA2PIM

--
73 de Robbert / TA2IX (aka PA3BKL)
The dutch guy living in Istanbul


pa2pim@...
 

Hi Robbert,
Tnx fr info. I've used EA displays in the past and they are of good quality. I have no speed issues, i.e. response time, with the LCD itself.
Also the Teensy 3.5 @ 48 MHz appear to be more then able to handle the tasks. Nice thing of the display you pointed at is that it also has a SPI I/F
That saves a lot of I/O pin's, something to keep in mind for future projects.

I suspect that what is happening at higher clock speeds that the timing of the control lines of the display do not stay within specs of the controller chip.
My display is of unknown origin obtained many moons ago on some flea-market and had been gathering dust for years. 
That suspicion is only based on earlier experience with the SPI interface and I have not really investigated it.
There are still lots of other and bigger fish to fry.

And just FYI and amusement here are some pictures on what I'm up to.

73, Pim, PA2PIM