83Plus:Ports:2E

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.

Synopsis

Port Number: 2Eh

Function: CPU Speed Adjustment

This port for reasons unknown has a slight effect on the CPU speed. It works in both the 6 MHz and 15 MHz modes. Every bit on the port affects the speed, but only bits 5 and 4 have any significant effects. The default value for this port is 45h on the TI-84 Plus Silver Edition and 45h 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 ~82% of normal speed
• 10: The CPU is running at ~99% of normal speed
• 11: The CPU is running at ~81% of normal speed

Write Values (bits 5 and 4)

• 00: Set the CPU to run at 100% of normal speed
• 01: Set the CPU to run at ~82% of normal speed
• 10: Set the CPU to run at ~99% of normal speed
• 11: Set the CPU to run at ~81% 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 0Eh.

Example

ld a,74h   ;Set the CPU to ~12.09 MHz/~4.8 MHz
out (2Eh),a

Credits and Contributions

• Michael Vincent: Documentation found here.