I use a Teensy 3.5 with Teensyduino 1.44, and I am currently writing a driver for a MCP2517FD CAN controller. The INT pin of MCP2517FD is connected to pin #38. I have written that the SPI is using that pin with SPI1.usingInterrupt (38). But I think that this line has no effect.

I have examined the SPI.h file and I found the usingInterrupt function (from line 468). I think this function is valid for Teensy 3.1/3.2, but has not been updated for Teensy 3.5 / 3.6. Adding "|| n == 38" at the end of line 473 solved my issue (#38 is PTC11).

I suggest the following replacement for this function:

#if defined(__MK20DX128__) || defined(__MK20DX256__)
void usingInterrupt(uint8_t n) {
if (n == 3 || n == 4 || n == 24 || n == 33) {
usingInterrupt(IRQ_PORTA);
} else if (n == 0 || n == 1 || (n >= 16 && n <= 19) || n == 25 || n == 32) {
usingInterrupt(IRQ_PORTB);
} else if ((n >= 9 && n <= 13) || n == 15 || n == 22 || n == 23
|| (n >= 27 && n <= 30)) {
usingInterrupt(IRQ_PORTC);
} else if (n == 2 || (n >= 5 && n <= 8) || n == 14 || n == 20 || n == 21) {
usingInterrupt(IRQ_PORTD);
} else if (n == 26 || n == 31) {
usingInterrupt(IRQ_PORTE);
}
}
#elif defined(__MK64FX512__) || defined(__MK66FX1M0__)
void usingInterrupt(uint8_t n) {
if (n == 3 || n == 4 || (n >= 25 && n <= 28) || (n >= 39 && n <= 42)) {
usingInterrupt(IRQ_PORTA);
} else if (n == 0 || n == 1 || (n >= 16 && n <= 19) || (n >= 29 && n <= 32) || (n >= 43 && n <= 46) || n == 49 || n == 50) {
usingInterrupt(IRQ_PORTB);
} else if ((n >= 9 && n <= 13) || n == 15 || n == 22 || n == 23 || (n >= 35 && n <= 38)) {
usingInterrupt(IRQ_PORTC);
} else if (n == 2 || (n >= 5 && n <= 8) || n == 14 || n == 20 || n == 21 || n == 47 || n == 48 || (n >= 51 && n <= 55)) {
usingInterrupt(IRQ_PORTD);
} else if (n == 24 || n == 33 || n == 36 || n == 56 || n == 57) {
usingInterrupt(IRQ_PORTE);
}
}
#endif

Best regards,

Pierre Molinaro