Future Teensy features & pinout

Doctors are petitioning govt to lockdown Australia. Looking more and more like a rough ride ahead for all on starship Earth. Best wishes to all.
 
We will need permission from PJRC for such a special thread on COVID-19.

I can appreciate that there may be some reluctance, not being directly Teensy product related. The relationship, if any, will be to understand the economic consequence. If permission were given, then some rules would have to be strictly observed - refrain from any political stance or comment would be one example.

The upside is benefits could be found. First, we could support the sense that "we are all in this together". This would have impact on our mental health and keep our spirits high. Second, I would be keen to see some ideas about how Teensy products might help. There seems to be a general viewpoint that more widespread testing needs to be achieved. Could we use our collective brainpower to come up with some ideas. Even if not successful in combating the virus, it would be fun to see what we dream up. Third, we should all learn a lot about different views and situations in different places worldwide.

By having a single thread for such comments, it would keep everything virus related in one place. That would be easier to moderate. We might all have a good laugh too at some of the wacky ideas that may emerge...
 
We will need permission from PJRC for such a special thread on COVID-19.

Sure, let's chat of the current events on another thread. Please feel free to start one in general discussion, and post a link to it here.

Then we'll temporarily close this thread. Plenty of feedback has already been written, and right now all work is going into 1062-based hardware and software. Will probably not re-open this until Teensy 4.1 is released.
 
I like to see the T5 have the ability to drive larger LCDs. 800x480 or higher. SPI would be too slow, parallel RGB would take up too many IOs.
MIPI-DSI would be a good option to go for.

I've seen buydisplay.com have some MIPI-DSI panels available but no example of driver code.

The Arduino Portenta H7 has I believe MIPI-DSI but no example sketch.

I've got a STM32F769I Discovery board that has a 4" 800x480 capacitive touch LCD via MIPI-DSI. The display is sharp and fast refresh.

Need also few Mbytes of RAM for frame buffer.
 
What about a proper heatsink on the MCU? one that also fixes the BGA to the PCB with enough flex and force in the fixture to keep things going after a Teensy has been pried off a breadboard, or exposed to mechanical stress.
Also, I'd recommend a thicker, more warp resistant PCB. (double meaning, no pun intended :cool: )
 
Will the 1170 have DACs as peripherals? These are useful to "glue" the digital world to the analogue world. (Note for our US cousins... there's no such thing as "gl") Tee hee.
 
I like to see the T5 have the ability to drive larger LCDs. 800x480 or higher. SPI would be too slow, parallel RGB would take up too many IOs.
MIPI-DSI would be a good option to go for.

I've seen buydisplay.com have some MIPI-DSI panels available but no example of driver code.

The Arduino Portenta H7 has I believe MIPI-DSI but no example sketch.

I've got a STM32F769I Discovery board that has a 4" 800x480 capacitive touch LCD via MIPI-DSI. The display is sharp and fast refresh.

Need also few Mbytes of RAM for frame buffer.

I second this! ^^^ would like to see higher res displays driven directly by the chip - seen some beautiful things on the development boards with LVGL and Qt.
 
According to NXP, 1170 will one 12 bit DAC. Why they chose to include only 1 rather than 2 or 4 makes little sense to me.

I was just thinking that it might be useful to be able to "synchronise" two Teensies together - in sort of "Lego" brick fashion. Perhaps allow one system clock to influence another one (or maybe even more), such that more than one DAC could be synchronised.

There may be other advantages of such a config... ?? Best done at chip level autonomously, but could be so at Teensy board level ??
 
More love for Vin, for easy seamless concurrent use of USB and Vin.

No additional LDO, but an ideal diode between VUSB and the LDO (currently TLV75733P) and ideally a second one for Vin.

Such as a pair of cheap LM66100, for VUSB and Vin. I think the VUSB solder bridge area could then be reclaimed to make room for some of it.
 
good idea!

Also it would be nice to have a LDO with a bit more max input voltage. This could help with adaptors to USB-C, which could provide more or could also erratically provide too much for the current Teensy (looking here at chinese power supplies or banks).
 
Obviously, everybody has a grab bag of favorite features. But I tend to think there are limits about what can be done.

I tend to think some of the constraints might be:
  • PJRC.COM is a small company, This tends to limit the number of designs to 1-2 per year.
  • Obviously the higher the price, the fewer people will buy new Teensies. Right now, the sweet spot is the $20-30 range for the consumer. Perhaps it can go a little higher, but I would suspect $40 or $50 may be the limit. I doubt the retail price of the Portenta H7 ($104) would be sustainable for the long term.
  • I wonder how important is backwards compatibility? Paul has done a heroic effort to make the Teensy 4.x compatible with the Teensy 3.x if you stick to the main devices (first serial port, first I2C bus, first SPI bus, position of the first 10 analog pins, position of the power/ground/VUSB pins), but of course once you get past the main devices, things are not as compatible between Teensies.
  • For many people (including me), having the main Teensy pins be breadboard/prototype board accessible is very important. However, having pins at 0.1" means much bigger chips to bring out more pins, which can drive up the cost.
  • I think one of the useful new features in the Teensy 4.1 is the solder pads to add 1-2 more memory chips, including 1 chip that might be persistent.
  • How important is USB host, ethernet, and hopefully wifi/bluetooth to people on the board directly?

So one thought that I've had is the basic Teensy 5.0 should be the size of the Teensy 4.1, and if possible the pinout should be the same as the 4.1 for those pins. This way, we won't need a revision E audio shield, etc.

No SD card on the Teensy 5.0. Instead use the area to bring out as many pins as we can, using a standard connector. Perhaps a ribbon connector, perhaps something else.

Come out with daughter boards that can mount either under the Teensy (or over it) to attach to the high density pin output and bring out the various functionality people want (JTAG debugging, display/camera, flexio, micro-SD card, etc.).

It would be nice if we had pads like the Teensy 4.1 for external memory. From one standpoint, it would be nice if there were two versions, where one had the chips attached, and the other didn't have chip support (given how few places in the world there are to order psram chips). But I can understand having multiple models is a cost to PJRC.

Personally, I would like to see a lipo battery JST-2 pin connector and a charger chip to charge lipo batteries from USB, but I can certainly live without it.

An alternative might be to grow the Teensy 5.0 by 0.2" wide. Have the standard pins from the Teensy 4.1 on the inner row, and all of the extra pins on the outer row. That would give us 48 additional pins. I don't know if we want the USB host, ethernet, and the inner pins to be in the same location as the Teensy 4.1. It might make sense to move these to the outer row pins, but I can also understand keeping them in the same position.

The main way I would probably use this is to mount stacking headers on the main pins, and then only mount headers above the board for the outer row pins. That way people wanting to use a traditional breadboard for the main pins can do so, but you could use jumper wires to connect the other pins. People who design PCBs, could design it to take both rows of pins.
 
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A wider form factor could span two parallel breadboards instead of one and still make more pins accessible.

A Problem is non-standard connectors. See 4.0 SD card. It is always a hack to make the SD work. A little wider footprint would have allowed to solder an SD socket directly.
Also, these connectors are not available everywhere and not everybody has access to digikey, etc, because spending 50€ for a pair of connectors will definitely sum up to the original cost of the Teensy 5.

Also important: a battery charger and power management. This would allow using the Teensy in mobile applications. For now it is again always a hack, use external modules, breakoutsm etc.
 
I fully second MichaelMeissner’s post #190

After having swallowed the disappointment that future Teensys will have rather less integrated analog stuff like DACs and ADCs an never offer satisfying resolution and low noise, my personal opinion tends now to omit specific peripherals on the small Teensy PCB and to request rather as many pins to be brought out as possible for maximum flexibility. USB-host, Ethernet, all that can either be put on shields for the breadboard party while advanced designers will be able to add these to their PCBs. The freed up few square millimeters are better used with a connector, so that still more pins can be used.

The idea of the double pin rows will greatly help as Michael described since it will satisfy the needs of everybody, the stackers, the breadboarders, and the PCBers.
 
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I really think that rather than the breadboard and longer breadboard form factor it's time to move to a breadboard and module release where the "5.1" equivalent is available on a castellated module rather than the breadboard friendly form factor. It allows bringing out more pins and is more convenient for integrating into larger projects.
 
One minor thing that would be useful is having solder jumpers that would add pull-up resistors for the I2C ports.

One of the things I might wish for is an update to the prop shield:
  • A simple audio subsystem like the PT8211 for mono sound output, plus an amplifier;
  • Two pins (not 11 and 13) that have voltage level shifters for APA102 and WS2812B LEDs. Perhaps pins 14 & 17, so you can use the Serial WS2812 library to drive the pins;
  • Flash memory;
  • Pull-up resistors for SCL/SDA;
  • Optionally motion sensors.

It would be nice if this card had some standard pinouts where you could attach a set of 3 or 4 cables to get easy access to Serial1, I2C1, etc. Maybe having a few set of pins for adding analog potentiometers, and push buttons. Maybe even a pinout for attaching a SPI display.

Note, Adafruit and Sparkfun are now adding Qwiik ports for their boards that use I2C. In a prop board rev 2, it would be useful to have at least one of these as well.

If you don't put a lipo battery on the Teensy 5, perhaps put it on the prop shield v2, similar to what Adafruit does for the Teensy -> Feather adapter (if there is USB power, the battery will be charged from the USB power, but not used -- if there is no USB power, it will use the battery -- Adafruit uses A7 with voltage dividers to give uses a rough idea of the amount of current remaining).
 
I really think that rather than the breadboard and longer breadboard form factor it's time to move to a breadboard and module release where the "5.1" equivalent is available on a castellated module rather than the breadboard friendly form factor. It allows bringing out more pins and is more convenient for integrating into larger projects.

I'm not sure exactly what you mean for the layout. If you mean a board that doesn't have holes per se, but just has castellated edges for soldering into a PCB, that may alienate some users if it was the only option.

The trouble with this is, not everybody is at that level in terms of soldering ability. For these people, it is nice that PJRC offers Teensies with the pins soldered in. They can use jumper wires on a breadboard to play with designs. Maybe later they will get boards without the pins, and solder away. While I am somewhat more experienced with the solder gun now, having the initial Teensies with the pins soldered in was what drew me to the Teensy in the first place, rather than other competing projects.

And I can imagine if you are the type that routinely plugs a Teensy into either a breadboard or prototype board with headers and then takes it out again, that having castellated edges would open up the Teensy to various cold solder joints and you might have to keep re-soldering it. With through hole pins, it is a lot more stable.
 
I'm not sure exactly what you mean for the layout. If you mean a board that doesn't have holes per se, but just has castellated edges for soldering into a PCB, that may alienate some users if it was the only option.
I'm suggesting that the second board in the 5 series would be in a new format, the first would still be in the traditional Teensy layout.
 
So one thought that I've had is the basic Teensy 5.0 should be the size of the Teensy 4.1, and if possible the pinout should be the same as the 4.1 for those pins. This way, we won't need a revision E audio shield, etc.

No SD card on the Teensy 5.0. Instead use the area to bring out as many pins as we can, using a standard connector. Perhaps a ribbon connector, perhaps something else.

I like this idea. In the space of the SD card, you could add 25 more pins at a 100 mil spacing. Not saying that's how it should be done but I could see at least 15 more pins. I could certainly make use of them for additional features on my CNC boards.
 
The upcoming 1170-based board will be called Teensy 4.something, probably 4.5. It definitely will *not* be Teensy 5.0. We probably won't call anything version 5 until Cortex-M55. The reality of this board is a faster Cortex-M7 and secondary Cortex-M4 with more or less the same peripherals as we have in Teensy 4.0 & 4.1, just more of them, plus the MIPI camera & display, openvg 2D-GPU, and gigabit ethernet.

I don't have any comments right now about all this talk of form factors and pinouts, other than I am reading it all & considering options...
 
Indeed MichaelMeissner’s post has good notes - and some others - some design choices based on the 1170 MCU probably on a napkin at PJRC ...

NXP hasn't posted package info yet? Except it has 93 more pins than 1062 [196 BGA] in a '289 BGA' for the 1170.

It seems there was a note the 1170 would not be on a 0.7" wide PCB? But a necessarily wider board to accommodate the MCU ... Not sure if hat is fiction or posted somewhere ... perhaps this thread?

To get the extra pins for T_4.1 (ethernet/QSPI/etc) the larger package (than used on T_4.0) with bigger BGA spacing was needed to escape the wires affordably on the 6 (?) layer board. So with 93 extra pins it seems it will be necessarily larger to have the same BGA spacing to work with.

Having components on the T_4.x bottom freed/maximized up topside space - doing castellated for direct solder would not allow for those - unless it was routed out.
 
One other thought is perhaps the library people should be thinking of ways to use the secondary processor in parallel to the main Teensy. Obviously this will take a lot of time after the Teensies are shipping (to at least beta folk) to iron out the bugs and such. It may be that it is too hard of a problem to add parallelism to the Arduino framework, but it may make sense to at least provide the tools to allow separation.

Obviously you want things to be configurable, since it is likely only one task will get the second processor. For example, one user with mixed support, may decide she/he wants to run audio playback in the secondary processor, perhaps another user would want to use it to control WS2812B LEDs, etc.
 
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