Realistic max SPI clock rate?

Not sure how fast the dedicated SPI hardware can be clocked, but FlexIO (which can be used to implement SPI) can reach at least 200 MHz.
 
According to the NXP datasheet, 30 MHz is the max for SPI (the LPSPI peripherals, not the FlexSPI). Many people have reported success at higher speeds, but anything over 30 MHz should be considered overclocking.
 
Thanks for the feedback. FlexIO sounds rather complex to implement but might be the way to go. I'll keep looking for overclocked LPSPI Teensy examples. If there's any recommended posts to read please drop a link!
 
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And working on a breadboard its wise to stick to below 30MHz anyway - I never got anything digitls to work reliably above 40MHz in that environment (due to lots of parasitic impedances).
 
Lenat said:
If there's any recommended posts to read please drop a link!
Click to expand...

If using the SPI library, you configure the clock speed with SPI.beginTransaction() and SPISettings. This is will documented.

SPI Arduino Library, connecting SPI devices to Teensy

www.pjrc.com www.pjrc.com

SPI.beginTransaction() - Arduino Reference

The Arduino programming language Reference, organized into Functions, Variable and Constant, and Structure keywords.
www.arduino.cc www.arduino.cc

If you wish to program the LPSPI hardware directly rather than use the SPI library, it is documented in the reference manual. Find the link under "Technical Information" on the Teensy 4.1 page.

Teensy® 4.1

www.pjrc.com www.pjrc.com

Using the LPSPI hardware directly is quite complicated. Most people prefer to use the SPI library because programming is so much simpler.
 
Thanks for the links Paul, I'm looking at the SPI Library first.

MarkT said:
And working on a breadboard its wise to stick to below 30MHz anyway - I never got anything digitls to work reliably above 40MHz in that environment (due to lots of parasitic impedances).
Click to expand...

How about soldered applications, instead of breadboard? Wires and breadboards can mess with SPI, but how about ideal conditions where the Teensy is directly soldered to a PCB?
 
Much higher so long as you have signals over a groundplane at a reasonable impedance, and you can add good (low inductance) decoupling to chips with SMT caps and low-value series resistors on datalines to reduce ringing.
 
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