Difference between revisions of "83Plus:Ports:2E"
From WikiTI
m (Forgot comment, plus defualt vaule 44h for 83se.) |
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'''Function:''' CPU Speed Adjustment | '''Function:''' CPU Speed Adjustment | ||
| − | + | Bits 4 and 5 can adjust the CPU speed to a certain degree. In order for the speed adjustment to work bit 1 must be set in the appropriate LCD Delay port according to the contents of port 20. In other words, if you wish to adjust the speed at 6mhz you must set bit 1 of port 29. Other bits of this port 2E may effect the speed but nothing significant. The default value for this port is 45h on the TI-84 Plus Silver Edition and 44h on the TI-83 Plus Silver Edition. | |
=== Read Values (bits 5-4)=== | === Read Values (bits 5-4)=== | ||
* 00: The CPU is running at normal speed (100%) | * 00: The CPU is running at normal speed (100%) | ||
| − | * 01: The CPU is running at ~ | + | * 01: The CPU is running at ~90% of normal speed |
| − | * 10: The CPU is running at ~ | + | * 10: The CPU is running at ~95% of normal speed |
| − | * 11: The CPU is running at ~ | + | * 11: The CPU is running at ~86% of normal speed |
| − | === Write Values (bits 5 | + | === Write Values (bits 5-4)=== |
* 00: Set the CPU to run at 100% of normal speed | * 00: Set the CPU to run at 100% of normal speed | ||
| − | * 01: Set the CPU to run at ~ | + | * 01: Set the CPU to run at ~90% of normal speed |
| − | * 10: Set the CPU to run at ~ | + | * 10: Set the CPU to run at ~95% of normal speed |
| − | * 11: Set the CPU to run at ~ | + | * 11: Set the CPU to run at ~86% of normal speed |
== Comments == | == Comments == | ||
| Line 27: | Line 27: | ||
== Example == | == Example == | ||
<nowiki> | <nowiki> | ||
| − | ld a,74h | + | ld a,0 |
| + | out (20h),a ;would be 6mhz | ||
| + | in a,(29h) | ||
| + | or 2 ;set bit 1 | ||
| + | out (29h),a | ||
| + | ld a,74h ;Set the CPU to ~5.1 MHz | ||
out (2Eh),a | out (2Eh),a | ||
</nowiki> | </nowiki> | ||
Revision as of 04:51, 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 06. |
Contents
Synopsis
Port Number: 2Eh
Function: CPU Speed Adjustment
Bits 4 and 5 can adjust the CPU speed to a certain degree. In order for the speed adjustment to work bit 1 must be set in the appropriate LCD Delay port according to the contents of port 20. In other words, if you wish to adjust the speed at 6mhz you must set bit 1 of port 29. Other bits of this port 2E may effect the speed but nothing significant. The default value for this port is 45h on the TI-84 Plus Silver Edition and 44h on the TI-83 Plus Silver Edition.
Read Values (bits 5-4)
- 00: The CPU is running at normal speed (100%)
- 01: The CPU is running at ~90% of normal speed
- 10: The CPU is running at ~95% of normal speed
- 11: The CPU is running at ~86% of normal speed
Write Values (bits 5-4)
- 00: Set the CPU to run at 100% of normal speed
- 01: Set the CPU to run at ~90% of normal speed
- 10: Set the CPU to run at ~95% of normal speed
- 11: Set the CPU to run at ~86% of normal speed
Comments
This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of Port 06h.
Example
ld a,0 out (20h),a ;would be 6mhz in a,(29h) or 2 ;set bit 1 out (29h),a ld a,74h ;Set the CPU to ~5.1 MHz out (2Eh),a
Credits and Contributions
- Michael Vincent: Documentation found here.
