Difference between revisions of "83Plus:Ports:29"
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| − | [[Category:83Plus:Ports:By Address|29 - LCD | + | [[Category:83Plus:Ports:By Address|29 - LCD Delay (6 MHz)]] [[Category:83Plus:Ports:By Name|LCD Delay (6 MHz)]] |
{{SE-Only Port|01}} | {{SE-Only Port|01}} | ||
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'''Port Number:''' 29h | '''Port Number:''' 29h | ||
| − | '''Function:''' LCD | + | '''Function:''' LCD Delay (6 MHz) |
This port removes the amount of delay needed between accesses to the lcd driver by adding tstates to the following instructions: | This port removes the amount of delay needed between accesses to the lcd driver by adding tstates to the following instructions: | ||
Revision as of 22:57, 7 August 2005
| 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 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. 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 tstates 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.
