Got my first Teensy 4.0s today.

jim lee

jim lee

Well-known member
I'm moving up from the teensy 3.2.How close are these wiring-wise are these to the 3.2 I'm used to? Code wise? And the package says lockable version. What's that mean?

Any more things to watch out for?

Thanks millions!

-jim lee
 
Haven't looked in some time - but goal was to keep same what could be. Only 3.3V signals welcome.
Compare the PJRC cards - they are more alike than different as far as the pins - though ALT/secondary options not so much maybe?
LOCKABLE is special order - nothing different if left unlocked and used normally. Once LOCKED - see the PJRC info page on that - only a properly encrypted HEX ... eHex ... can be uploaded to execute and any effort to pull the code from Flash will find encrypted bit jumble.
 
Thanks!

Also, it looks like all I need is a coin battery and it's a real time clock? This true?

-jim lee
 
Yes, but don't expect the battery to last more than a couple of months. It's ok for keeping the clock over short power outages but for long term preservation a dedicated RTC is still better.
 
How about a pizeo speaker. I hooked them directly to my 3.2 pins. Am I going to need some sort of driver to drive this now?
 
Between 2020 and 2022, I added this page about Teensy compatibility to the unofficial Teensy wiki project:
I also created this google spreadsheet on various microprocessor layouts:
In terms of your pizeo speaker, it depends on how you hooked it up.
  • If you hooked it up to ground & pins 3-6, 8-9, or 22-23 (A8-A9) and drive it with PWM, you should be fine.
  • If you hooked it up to ground & pins 20-21 (A6-A7) and drive it with PWM, you will need to move it, as these pins are not PWM in the 4.0.
  • If you hooked it up to ground & pin A14 and used pin A14 as a digital to analog (DAC) pin to make sound to drive it, you will need to completely rethink your code. The Teensy 4.0 and 4.1 do not offer a DAC pin. What was pin A14 on the Teensy 3.2 is the on/off pin on the Teensy 4.0.
  • Note, for I2S sound output (usually through the Teensy audio shield), the Teensy 3.1/3.2/3.5/3.6 uses completely different pins from the Teensy 4.0/4.1. You need to use a different audio shield between the Teensy 3.1/3.2/3.5/3.6 and the Teensy 4.0/4.1 lines.
  • Likewise, you can't use the old prop shield for audio because the Teensy 4.0 doesn't have the audio output pin (A14).
  • If you don't use SPI devices, pins 10 and 12 can be used as MQSR/MQSL pins which can drive a speaker in some fashion.
 
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