83Plus:Ports:2F

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Revision as of 06:03, 23 August 2005 by Jim e (Talk | contribs)

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This port only exists as a distinct port on the TI-83 Plus Silver Edition, the TI-84 Plus, and the TI-84 Plus Silver Edition. On the standard TI-83 Plus, it acts as a shadow of port 07.

Synopsis

Port Number: 2Fh

Function: LCD Wait Delay

After every write to the LCD bit 1 of port 2 resets for a certain amount of time. This port controls that amount time.


Read Values

  • This port reads the last vaule written to it.


Write Values

  • Bits 2-4 contorl the amount of time when port 20 contains 1. The following values tell the amount of time.
    • 00 = ~3.2 microseconds
    • 01 = ~7.4 microseconds
    • 10 = ~11.7 microseconds
    • 11 = ~16.0 microseconds
  • Bits 2-4 contorl the amount of time when port 20 contains 2. The following values tell the amount of time.
    • 000 = ~3.2 microseconds
    • 001 = ~7.4 microseconds
    • 010 = ~11.7 microseconds
    • 011 = ~16.0 microseconds
    • 100 = ~20.2 microseconds
    • 101 = ~24.5 microseconds
    • 110 = ~28.8 microseconds
    • 111 = ~33.0 microseconds
  • Bits 5-7 contorl the amount of time when port 20 contains 3. The following values tell the amount of time.
    • 000 = ~3.2 microseconds
    • 001 = ~7.4 microseconds
    • 010 = ~11.7 microseconds
    • 011 = ~16.0 microseconds
    • 100 = ~20.2 microseconds
    • 101 = ~24.5 microseconds
    • 110 = ~28.8 microseconds
    • 111 = ~33.0 microseconds


Comments

This value really shouldn't be changed. TI-OS depends on this being set high enough to function for the LCD delay.

Also the 83+SE has this port set to 4A as defualt, the 84+(SE) has this port set to 4B as defualt.


Credits and Contributions

  • James Montelongo