Difference between revisions of "83Plus:Ports:29"

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(Added info on effect)
(Added bit 1 info)
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=== Usage ===
 
=== 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.
+
When Bit 1 is set the effects of speed adjustment port 2E can be seen.
  
 
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.
 
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.
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This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of [[83Plus:Ports:01|Port 01h]].
 
This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of [[83Plus:Ports:01|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.
+
Bits 0&1 are reset on the 83+SE and set on the 84+(se).
  
 
The effect of this port is only seen if the contents of [[83Plus:Ports:20|port 20h]] equals 00.
 
The effect of this port is only seen if the contents of [[83Plus:Ports:20|port 20h]] equals 00.

Revision as of 01:06, 22 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 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

When Bit 1 is set the effects of speed adjustment port 2E can be seen.

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 are reset on the 83+SE and set on the 84+(se).

The effect of this port is only seen if the contents of port 20h equals 00.


Credits and Contributions

  • Michael Vincent: Documentation as found here.
  • James Montelongo: Documentation found at here.