83Plus:Ports:86

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 06. On the TI-83 Plus Silver Edition, this port has no effect.

Synopsis

Port Number: 86h

Function: USB Miscellaneous Events

This port reports when various device-level USB events occur.

Read Values

Reading from this port also clears it. Remember the value you read, because you can't go back and read it again.

• 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.

Write Values

• No effect

Comments

This port is used to report various bus events, which are not associated with any particular endpoint. Note that this port (probably) only works if port 5B bit 0 is set. Port 8B might also act as a mask for this port (note that that port is normally set to A1h in host mode, and 05h in peripheral mode.)