Is the T4.1 RTC clock required?

[jensa]

Hi,
I'm doing a custom T4.1. My first board worked well, but for my second board I'm trying to optimize a bit. The T4.1 has two crystals in the reference design - one for the MCU and one for the RTC. Is the RTC crystal required if you don't need the RTC features?

J

 

[PaulStoffregen]

The chip has a low accuracy 32 kHz oscillator which is supposed to be automatically used if no RTC crystal is present. So at least in theory, it should work.

As a practical matter, all software for Teensy has been developed and tested with a real RTC crystal, so there's a chance some software may depend on it in unexpected ways. Might be wise to desolder the crystal from a Teensy 4.1 and test your program before committing to a custom PCB.

 

[jensa]

Thanks! I'll desolder and test!

J