Onboard Red Led Blinks 9 Times


New member
I was working on a project using the Teensy 4.1 and whenever I attempt to utilize the SPI1 or SPI2 peripherals the red program led flashes 9 times (repeating after a small delay). I can't find any documentation on what different blinking patterns indicate so I wanted to check here to see if anyone else has encountered the 9 blink pattern and, if so, what the problem was. I have no problem utilizing SPI0 its just the other two that are giving me the error.

Thank you.

Also, I'm utilizing Rust to program the Teensy, so if no one else has ever encountered the 9-blinking red led the issue may be related to the rust toolchain I'm using (however, I'm pretty sure that's not the issue).
The explanation for all of the troubleshooting blink codes can be found at the bottom of <this> page.

Hope that helps . . .

Mark J Culross
Based upon the explanation for 9 blinks, checking for a Crash Report might provide further insight into what's going wrong.

To view the Crash Report, add the following in your setup() function & open the Serial Monitor in the Arduino IDE to see any report that may be generated:

while(!Serial) ;
if (CrashReport)

See if that report provides any clues . . .

Mark J Culross
Looks like it was in fact a toolchain issue. Thank you for the link to the blink codes I'm checking in with the imxrt-hal rust folks to see why the LPSPI3 interface is hanging on initialization.