|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 01. On the TI-83 Plus Silver Edition, this port has no effect.|
Port Number: 51h
Function: USB Enable Timer
USB timing comes from a separate 48 MHz crystal. This crystal is normally left disabled unless USB is being used. After starting the crystal, this port controls how long the hardware waits before enabling the USB hardware. Counts in 2-tick increments from the 32768 Hz crystal.