83Plus:Ports:2A
| 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 02. |
Synopsis
Port Number: 2Ah
Function: LCD Delay (15 MHz)
This port works in the same manner 29 does, but only when the calculator is set at 15mhz. It removes the amount of delay needed between accesses to the lcd driver by adding tstates to the following instructions:
- out (010h),a
- in a,(011h)
- out (011h),a
Usage
Bits 0&1 are unknown, but don't seem to directly remove the needed delay. They are set on both the 83+SE and 84+(SE).
Bits 2-7 control the amount of delay added at specified instructions. To calculate the tstates added divide the contents of port 2A by 4 and round off. NOTE: The contents of this port should NOT be less than 0Ch or the LCD will no longer update.
Comments
This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of Port 02h.
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.
