83Plus:Ports:29
| 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 01. |
Synopsis
Port Number: 29h
Function: LCD Delay (6 MHz)
This port removes the amount of delay needed between accesses to the LCD driver by adding a delay to any instruction which reads from or writes to ports 10 or 11, as well as the mirror ports 12 and 13.
Usage
Bits 0 and 1 are unknown, but don't seem to directly remove the needed delay. On the 83+SE these are reset, on the 84+(SE) these are set.
Bits 2-7 control the amount of delay added at specified instructions. To calculate the number of clock cycles added, divide the contents of port 29 by 4 and round off.
Comments
This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of Port 01h.
Bits 0&1 seem to tie to port 2E, they affect the cpu speed reduction the port 2e contorls. Though their exact purpose is not known.
The effect of this port is only seen if the contents of port 20h equals 00.
