83Plus:Ports:2A - Revision history

Thepenguin77 at 03:49, 28 October 2011

2011-10-28T03:49:23Z

Thepenguin77 at 03:09, 28 October 2011

2011-10-28T03:09:54Z

Thepenguin77 at 22:44, 5 July 2011

2011-07-05T22:44:34Z

Jim e: added 2e info

2006-03-14T14:01:51Z

added 2e info

Jim e: tied to 2e

2005-08-22T11:23:18Z

tied to 2e

Jim e: minor change

2005-08-21T20:40:46Z

minor change

Jim e: Added info on effect.

2005-08-21T20:31:24Z

Added info on effect.

FloppusMaximus: /* Synopsis */ this too

2005-08-08T21:54:12Z

‎Synopsis: this too

Jim e: Added port info

2005-08-08T05:55:47Z

Added port info

New page

[[Category:83Plus:Ports:By Address|2A - LCD Delay(15 MHz)]] [[Category:83Plus:Ports:By Name|LCD Delay (15 MHz)]]
{{SE-Only 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 [[83Plus:Ports:02|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.

== Credits and Contributions ==
* '''Michael Vincent:''' Documentation as found [http://michaelv.org/programs/calcs/ports/port2a.html here].
* '''James Montelongo:''' Documentation found at [http://www.geocities.com/jimm09876/calc/port2a.html here].

@@ Line 12: / Line 12: @@
 * Bit 0 enables the effects of the flash delay controlled by port 2E.
 * Bit 1 enables the effects of the ram delay controlled by port 2E.
-* 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 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.
+* 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 2A by 4 and round off. '''NOTE:''' The contents of this port should NOT be less than 0Ch or the LCD driver will no longer respond.
 == Comments ==

@@ Line 10: / Line 10: @@
 === Usage ===
+* Bit 0 enables the effects of the flash delay controlled by port 2E.
-When Bit 1 is set the effects of speed adjustment [[83Plus:Ports:2E|port 2E]] can be seen.
+* Bit 1 enables the effects of the ram delay controlled by port 2E.
+* 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 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.
 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 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 ==

@@ Line 11: / Line 11: @@
 === Usage ===
-Bits 0 and 1 are unknown, but don't seem to directly remove the needed delay. They are set on both the 83+SE and 84+(SE).
+When Bit 1 is set the effects of speed adjustment [[83Plus:Ports:2E|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 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.
@@ Line 17: / Line 17: @@
 == Comments ==
 This port is not available on the normal TI-83+. On the normal TI-83+ this port is a shadow of [[83Plus:Ports:02|Port 02h]].
 The effect of this port is only seen if the contents of [[83Plus:Ports:20|port 20h]] equals 01.

@@ Line 7: / Line 7: @@
 '''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 a delay to any instruction which reads from or writes to ports [[83Plus:Ports:10|10]] or [[83Plus:Ports:11|11]], as well as the mirror ports 12 and 13.
+This port works in the same manner 29 does, but only when the calculator is set at 15mhz and if port 20 equals 01. It 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 [[83Plus:Ports:10|10]] or [[83Plus:Ports:11|11]], as well as the mirror ports 12 and 13.
 === Usage ===

@@ Line 1: / Line 1: @@
 [[Category:83Plus:Ports:By Address|2A - LCD Delay(15 MHz)]] [[Category:83Plus:Ports:By Name|LCD Delay (15 MHz)]]
-{{SE-Only Port|0A}}
+{{SE-Only Port|02}}
 == Synopsis ==

@@ Line 20: / Line 20: @@
 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.
 == Credits and Contributions ==
 * '''Michael Vincent:''' Documentation as found [http://michaelv.org/programs/calcs/ports/port2a.html here].
 * '''James Montelongo:''' Documentation found at [http://www.geocities.com/jimm09876/calc/port2a.html here].