paoloboatto
Member
@MorganS: Is the GPS running off the Teensy 3.3V? On a breadboard? It may be a power draw issue? My T_3.6 could power the GPS, I was not using SD card - but I did pull 3.3v from T_3.6 in two spots to feed the power rail on the breadboard to the GPS. Working on same project somebody else was using external power (with common GND) on the GPS as his similar unit was failing to function - so the power draw may be an issue as the SD does draw some current … as it makes noise.
@paoloboatto - interesting F_CPU speed change helped - what was the F_CPU when it was failing - 180/216/240/256?
It was the default 180MHz. To further investigate you can also change the SPI clock speed