Hi there,
Yea, that is a PITA in LIBs i see it now and then, Look for an near alternative, even a sparkfun or Adafruit or a manufactures competitor, also the versions sometimes older BSP have the hook and then the new ones drop it because it wasn’t used often… Yea looking under the hood for stuff now… LOL 
You want to poll it for some error or status? Stepper driver ,
You read the uart instead of an INT pin.
I asked the AI too.
What actually works (no extra pin)
- Read
IOIN.DIAGover UART.
The IOIN register mirrors the current logic level of the DIAG pin internally. Poll it on a timer and you’ve effectively “read DIAG” without wiring it to the MCU. - (Better) Read the detailed status bits over UART.
UseDRV_STATUS(and friends likeGSTAT,SG_RESULT) to check for the exact conditions you care about (stall, OT/OTPW, short, standstill, etc.). Many people wire DIAG only to catch “something’s wrong”; readingDRV_STATUStells you what and avoids false positives.
Hmm, ??
HTH
GL 
PJ 