83Plus:Ports:40 - Revision history

FloppusMaximus at 21:05, 30 March 2005

2005-03-30T21:05:21Z

FloppusMaximus at 05:20, 30 March 2005

2005-03-30T05:20:54Z

FloppusMaximus: /* Example */

2005-03-29T22:00:31Z

‎Example

Dan Englender: Added categories

2005-03-28T18:05:29Z

Added categories

JasonM at 03:30, 27 March 2005

2005-03-27T03:30:02Z

JasonM at 03:16, 27 March 2005

2005-03-27T03:16:03Z

JasonM at 03:15, 27 March 2005

2005-03-27T03:15:21Z

New page

== Synopsis ==
'''Port Numbers:''' 40h through 48h

'''Function:''' Clock Control Port (as shown on the mode screen)

These ports allow the TI-84+/SE calculators to have a clock that can keep time, even when the calulator is turned off. The TI-83+/SE does not have this functionality.

''For further information on the clock, read the documentation for ports [[83Plus:Ports:41|41h-44h]] and ports [[83Plus:Ports:45|45h-48h]].

=== Read Values ===
* Bit 0: Set to 1 if the clock is enabled, 0 if it's disabled.
* Bit 1: Set command bit, see the comments.

=== Write Values ===
* Bit 0: Outputting with this bit enabled will turn on the clock, with it disabled turns off the clock.
* Bit 1: Set command bit, see the comments.

== Comments ==
If you play with bit 1, you notice that you can turn it on and off as you would bit 0. Still, the actual value of this bit is totally useless. All that matters is if you turn the bit on, then the clock is set (the values in ports [[83Plus:Ports:41|41h-44h]] are copied to [[83Plus:Ports:45|45h-48h]].) Still, you can't simply output 2 to set the clock, as if bit 1 was already on, it wouldn't actually set (the set only occurs if the bit is changed from 0 to 1.) The example code shows how to start the clock.

== Example ==
<nowiki>; This will set the clock back to it's start time
xor a
out (41h), a
out (42h), a
out (43h), a
out (44h), a

; This assures that the set command bit is off
ld a, 1
out (40h), a

; And set (and start) the clock
ld a, 3
out (40h), a</nowiki>

== Credits and Contributions ==
* '''Michael Vincent:''' Initial Documentation

@@ Line 1: / Line 1: @@
 [[Category:83Plus:Ports:By_Address|40 - Clock Control]] [[Category:83Plus:Ports:By_Name|Clock Control]]
 == Synopsis ==
 '''Port Number:''' 40h

@@ Line 1: / Line 1: @@
-[[Category:83Plus:Ports:By_Address|40 - Clock Control]]
+[[Category:83Plus:Ports:By_Address|40 - Clock Control]] [[Category:83Plus:Ports:By_Name|Clock Control]]
 [[Category:83Plus:Ports:By_Name|Clock Control]]
 == Synopsis ==
 '''Port Number:''' 40h

← Older revision		Revision as of 18:05, 28 March 2005
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		+	[[Category:83Plus:Ports:By_Address\|40 - Clock Control]]
		+	[[Category:83Plus:Ports:By_Name\|Clock Control]]
	== Synopsis ==		== Synopsis ==
	'''Port Number:''' 40h		'''Port Number:''' 40h

@@ Line 22: / Line 22: @@
 == Example ==
-  <nowiki>; This will set the clock back to it's start time
+  <nowiki>; This will set the clock back to its start time
 xor a
 out (41h), a

@@ Line 2: / Line 2: @@
 '''Port Number:''' 40h
-'''Function:''' Clock Control Port (as shown on the mode screen)
+'''Function:''' Clock Control Port
 These ports allow the TI-84+/SE calculators to have a clock that can keep time, even when the calulator is turned off. The TI-83+/SE does not have this functionality.