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This port only exists on the the TI-84 Plus and the TI-84 Plus Silver Edition. On the standard TI-83 Plus, it acts as a shadow of port 0B. On the TI-83 Plus Silver Edition, this port has no effect.


Port Number: 8Bh

Equivalent HDRC port: MGC_O_HDRC_INTRUSBE (0x0B)

Function: USB Events Mask

This port is a mask for what errors port 86 will report.

Set the corresponding bits here to receive notifications via port 86.


  • Bit 0: Possibly set if the bus has been suspended (no activity for some length of time.)
  • Bit 1: Unknown; probably related to HNP and/or SRP.
  • Bit 2: Set if a bus reset has occurred (both D+ and D? pulled low for some length of time.)
  • Bit 3: Unknown.
  • Bit 4: Possibly set if a device has been connected (D+, or maybe D?, pulled high for some length of time.)
  • Bit 5: This usually indicates that something was unplugged.
  • Bit 6: Unknown; probably related to HNP.
  • Bit 7: Calculator cannot provide sufficient power. Usually caused by low batteries, although, some devices cause this every time.