83Plus:Ports:2F

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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 0 and 1 control the amount time, the following values tell by how much.
    • 0 = ~3.5 microseconds
    • 1 = ~8 microseconds
    • 2 = ~10.5 microseconds
    • 3 = ~15 microseconds
  • Bits 2-7: The function of these bits are unknown.


Comments

NOTE: The timings above are ROUGHLY estimated.

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