Missing pin descriptions for Teensy 4 on web site documentation...?

S

smarrocco

Active member
Looking at the documentation for the Teensy 4.0 pinouts on https://www.pjrc.com/teensy/pinout.html, there appears to be a few missing:

  • MISO 1 (MISO and MISO2 are present)
  • CS1 (CS and CS2 are present)
  • Alternates for the SPI pins do not appear (ghosted green blocks), yet they do for the Teensy 4.1.
There appears to be some discussion on the forums some time ago about this, but it doesn't appear that the web page was updated with the current information....?
 
MISO1 and CS1 are in the same location as the Teensy 4.1 (i.e. pin 0 is CS1 and pin 1 is MISO1). I had thought at one point Paul was going to update online pinout.html file (he can't change the card that comes with the Teensy 4.0 until the next time they print up the card stock).

  • I believe pins 0..33 map into the same hardware pin on both the Teensy 4.0 and 4.1.
  • The Teensy 4.1 brings 8 more pins (34..41) that are not brought out in the Teensy 4.0. This means, the alternate MISO1 pin (39) is not brought out in the Teensy 4.0.
  • On the Teensy 4.1, pins 42..47 are connected to the micro SD card reader, while on the Teensy 4.0, pins 34..39 are setup for attaching the micro SD card reader. I.e. pin 42 on the Teensy 4.1 is DAT1 or MISO2, while on the Teensy 4.0 pin 34 is DAT1 or MISO2.
 
Thank you Michael. Knowing that the pinouts between the T4 and T4.1 are the same helps. Yes, I figured that the cards sent out to people could not be updated automatically ;)

In addition to the updating of the web page info, a couple other suggestions for the documentation I'd like to make include:

-For labels involving SPI or other multiples, instead of "MISO, MISO1 and MISO2", perhaps "MISO0, MISO1 and MISO2" or "MISO1, MISO2 and MISO3". I'm sure there's some legacy involved there, but it's a bit unintuitive with lots of pins labeled as such.

-Addition of the "block descriptions" for types of pins to the models that don't show it on the left for consistency, i.e. "Analog Pins/yellow block", "SPI Pins/Green Block".

Again, I suspect the legacy for this web page is that it is a direct lift from the printed cards and thus is structured by the printed formats of those cards.
 
There is a LOT of information, that could be added here. The question has always been how much is too much for the majority of people?

For myself, I want all of the data, so I created my own:
1723726703063.png

Here is one page of my excel document, that I keep up at: https://github.com/KurtE/TeensyDocuments/blob/master/Teensy4x Pins.xlsx
The issue is that a lot of this information is sort of cryptic. Things like, the GPIO pin numbers I show the normal mode of pins, like teensy pin 0 is shown as on GPIO port 1, pin 3... But at startup the pins are switched to High speed, so in usage this pis Port 6 pin 3...

There is a lot of information here, that is not on the card that comes with the boards, like several other sub-systems, like:

FlexIO - This sub-system allows one to setup the three different FLEXIO objects which these pins as well as timers and shifters, to mimic other types of objects. Like Serial ports, SPI ports, Camera input, Parallel display output, etc.

XBAR - Hard to explain some of the different usages, but for example can be used with the Hardware Serail. For example you can use any of the XBAR pins instead of the RX pins associated with a serial port. The SerialX.setRX... calls are setup to allow this.

CSI - Camera interface, there are enough of these pins exposed for the Teensy 4.1 to allow 4-bit bus inputs from cameras, which we have done some playing with for a few cameras.

...

The question is how much of this information is useful to most users? Or when do uses hit information overload...
Also if Paul would now come out with a new version of the card, how much of it would we change? Like maybe change PWM to just
a color bar, maybe another color bar for XBAR...

We probably need something like multiple tiers of information, sort of like what Arduino has done with some of their boards.
Like the pinout information for the Arduino GIGA
The first part, give most of the basic needed stuff. They then have a disclaimer page, and then breakout most all of the information
about each of the pins.

Likewise: they have a "Cheat sheet" page, with links that give some additional information on some of the different sub-systems....
Probably a wiki.

But that is a lot of work and only one Paul.
 
The printed cards won't change anytime soon. Short version of the story... the printing shop raised prices pretty substantially, but allowed us to place 1 last order at the original price. We ordered a large quantity, enough to last well into 2025.

I believe we're already linking from the product pages (just below the pinout card info) to another thread with an older version of Kurt's expanded pinout chart. Maybe other places should also have links added? Maybe to a new thread?
 
And FWIW, in addition KurtE's wonderful document, I have a google spreadsheet that I try to keep up to date.

  • https://docs.google.com/spreadsheets/d/1LSi0c17iqtvpKuNSYksMG306_FpWdJcniSRR6aGNNYQ/edit?usp=sharing
  • The first sheet compares the pin layout of all arm based Teensys that use through hole pins (3.1/3.2, 3.5, 3.6, 4.0, 4.1, and LC). The 3.0 is also in the document, but usually the 3.0 columns are hidden. I did not include the MicroMod in this sheet.
  • The second sheet gives a quick comparison between the Teensies (amount of memory, # UARTs, # I2C buses, etc.)
  • The third sheet lists the pinout of many of the Teensy oriented shields.
  • There is a MicroMod specific sheet.
  • There is a sheet that lists many of the common I2C addresses for devices that I've used or might be interested in.
  • There is a sheet that lists the pinouts of some of the through hole or SMT chips I've used.
  • There is a sheet on Raspberry Pi pinouts, but I haven't updated it in quite some time.
  • The other sheets lists various other processor families (QT PY boards/BFFs, Feather/feather wings, ItsyBitsy, some ATmega boards, etc.).
 
Last edited:
defragster said:
the online card could be edited as a reference?
Click to expand...

The online-only info already has this edit:

1723760010492.png



defragster said:
Links there to 'added info thread/post'
Click to expand...

Yes, I'd be happy to add a link to a forum thread where more detailed info is given. The Teensy 4.1 page has such a link.

Is there a thread or message with Kurt's spreadsheet or something similar for Teensy 4.0? The info in msg #4 and in the older thread is for Teensy 4.1.
 
This is all good info, thank you all.

When you are all mentioning the "online card" (https://www.pjrc.com/store/teensy40.html#pins), I can see that that has a correction at the bottom.

The page to which I'm referring (https://www.pjrc.com/teensy/pinout.html) and the PDFs to which that points appear to be the same as the printed cards that do not show the updates in addenda.

@Kurt, thank you for the chart(s) you created. Very useful.

My engineering department has a sign on a wall that says "If you have the information in more than one place, the majority will be incorrect. ;)

Ultimately, perhaps the online version(s) of those multiple web pages could all be linked to the same, updated imagery.
 
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