83Plus:Ports:8C
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Revision as of 20:22, 27 October 2011 by Thepenguin77 (Talk | contribs)
| 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 04. On the TI-83 Plus Silver Edition, this port has no effect. |
Synopsis
Port Number: 8Ch (LSB), 8Dh (MSB)
Function: USB Frame Counter
These ports show the current value of the USB frame counter.
Read Values
- Port 8C: Bits 0-7 of the frame counter.
- Port 8D: Bits 8-10 of the frame counter.
Write Values
- No effect
Comments
These two ports indicate the frame counter value used (presumably) in the most recently sent or received start-of-frame packet. (In normal operation, SOFs are sent by the host, once per millisecond, and contain an 11-bit counter value.) These ports can be used for timing, or simply as an indication that USB is working (since the USB controller will not generate SOFs unless a device is connected.)
