WikiTI - User contributions [en]

Notable programs

2008-07-31T18:14:26Z

Nyquist562: Updated 2007 POTY

Here is a list of notable programs released by the TI Z80 community.
If you think a program has been forgotten, just add it.

For each program, please indicate : author, last version and release date, ticalc.org (or other if not available) URL, 1 or 2 screenshots, and a few words about it.

=Games=
==Puzzle==
* Ztris 1.3.2 ~ by Tijl Coosemans ~ http://www.ticalc.org/archives/files/fileinfo/207/20791.html
* Crates3D 1.1 ~ by Badja ~ http://www.ticalc.org/archives/files/fileinfo/192/19293.html
* Orzunoid ~ by Patrick Davidson ~ http://www.ticalc.org/archives/files/fileinfo/110/11033.html
==Action==
* Acelgoyobis ~ by CoBB ~ http://www.ticalc.org/archives/files/fileinfo/355/35586.html
* Bubble Bobble 1.0beta ~ Dan "dwedit" Weiss ~ http://home.comcast.net/~alanweiss3/dwedit/bubblebobble/index.html
* Invaded ~ by James Vernon ~ http://www.ticalc.org/archives/files/fileinfo/206/20692.html

==Adventure==
* Desolate ~ tr1p1ea ~ http://www.ticalc.org/archives/files/fileinfo/348/34879.html

==Racing==
* Tiny Carz ~ LÃ©o Ducas ~ http://www.ticalc.org/archives/files/fileinfo/391/39185.html

==First person shooter==
* Gemini ~ Hans "Coelurus" TÃ¶rnqvist ~ http://www.ticalc.org/archives/files/fileinfo/247/24743.html
* Wolfenstein83 ~ Peter Bucher ~ http://www.ticalc.org/archives/files/fileinfo/277/27767.html
* zDoom 0.12 ~ http://www.ticalc.org/archives/files/fileinfo/360/36062.html

==Platform==
* sqrxz ~ by Jimmy Mardell ~ http://www.ticalc.org/archives/files/fileinfo/144/14494.html
* Super Mario 1.2 ~ Sam Heald ~ http://www.ticalc.org/archives/files/fileinfo/192/19225.html

=External links=
* Ticalc.org's Program Of The Year : [http://www.ticalc.org/community/awards/poty/2003.html 2003] [http://www.ticalc.org/community/awards/poty/2004.html 2004] [http://www.ticalc.org/community/awards/poty/2005.html 2005] [http://www.ticalc.org/community/awards/poty/2006.html 2006] [http://www.ticalc.org/community/awards/poty/2007.html 2007]

{{stub}}

83Plus:BCALLs:8054

2007-05-10T00:52:40Z

Nyquist562: Added comment about effect of call of reg. A

[[Category:83Plus:BCALLs:By_Name:Memory|FlashToRAM2]] [[Category:83Plus:BCALLs:By_Name|FlashToRAM2]] [[Category:83Plus:BCALLs:By_Address|8054 - FlashToRAM2]]
== Synopsis ==
'''Unofficial Name:''' FlashToRAM2

'''BCALL Address:''' 8054

Copy data to RAM from either Flash or RAM.

=== Inputs ===
* AHL = source address
* DE = destination address
* BC = number of bytes to copy

=== Outputs ===
* AHL advanced by BC bytes
* DE advanced by BC bytes
* BC = 0

=== Destroys ===
* [[83Plus:RAM:8100|ramCode]]

== Comments ==
This is almost exactly equivalent to the OS [[83Plus:BCALLs:5017|FlashToRAM]].

Note that the high bits of A are masked out appropriately (so, for instance, passing A = 7F will read from the boot page regardless of the hardware version.) Set A = 0 to copy data from the main RAM; you cannot use this routine to copy data from the extra RAM.

In experimenting with this BCall, I have discovered that the register A is often disrupted after this call returns
---Nyquist562---

Talk:83Plus:Software:Extended RAM Manager

2007-05-09T02:28:28Z

Nyquist562:

I have actually created several various programs for variable storage in 'unused' app pages. But then I started thinking, many other applications use this area, and was disouraged, but what if there was a standard for extrapolative RAM data storage? I really like your idea of the standard, but what if the new standard were to be integrated into TI-OS?

Then i thought about using the standard VAT. In a VAT entry, one byte designates the Flash Page (or zero if in RAM), but the leading bit of that number is 'insignificant,' (e.g. if you were to enter 89h instead of 09h, the VAT would still theoretically be pointing to the same place) and if this 'insignificant' bit were to be used for specifying storage on an 'unused' RAM page, that would be quite convenient.
So, instead of 85h pointing to 05h ROM page, it would really point to page 85h, an 'unused' RAM page.

---Nyquist562---reardonshs@yahoo.com

83Plus:BCALLs:42F1

2007-04-12T00:58:42Z

Nyquist562: carry, not 'cary'

[[Category:83Plus:BCALLs:By Name:Variable|ChkFindSym]] [[Category:83Plus:BCALLs:By Name|ChkFindSym]] [[Category:83Plus:BCALLs:By Address|42F1 - ChkFindSym]]
== Synopsis ==
'''Official Name:''' ChkFindSym

'''BCALL Address:''' 42F1

Recalls various pointers and information for a symbol in the VAT.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable (with proper initial defining byte, see example)

=== Outputs ===
* HL = VAT pointer
* DE = Data location (to the best of my knowledge, please confirm this)
* B = Flash Page, or 0 if in RAM
* C = Length of Varibale Name
* A = 'unknown'
* carry flag is set if the variable is not found in the VAT

=== Registers Destroyed ===
'All'

== Example ==
<nowiki>
ld hl,varname
B_CALL Mov9toOp1
B_CALL ChkFindSym
jr c,notfound ;carry flag is set if the VAT entry is not found
ex de,hl ;put data pointer into hl
xor a
cp b ;see if b is 0, and the program is in the ram
jr z,unarchived ;if so, jump to unarchived

;do something to get it into RAM

unarchived:

;do something once it is in RAM

varName:
.db AppVarObj, "APPVAR",0
</nowiki>

Z80 Routines:Memory:RAM Access

2007-04-12T00:25:04Z

Nyquist562: Created a page showing RAM page access (someone please proof read this!)

[[Category:Z80 Routines:Memory|RAM Access]]
[[Category:Z80 Routines|RAM Access]]

==RAM page Access==
This is a routine to easily access those RAM pages generally inaccessable.

<nowiki>;=======READ/WRITE DATA FROM/TO RAM PAGE=======
;inputs: hl=offset of where to start reading data
; (ranges from 4000h-7FFFh for READING the 'Unused' RAM page)
; or (from 8000h-BFFFh for WRITING to the 'Unused' RAM page)
; bc=number of bytes to copy
; de=where to save the data
; (ranges from 4000h-7FFFh for WRITING to the 'Unused' RAM page)
; or (from 8000h-BFFFh for writing to the 'standard' RAM page)
; RAMPAGE=new page to read/write

in a,(06h)
push af
ld a,RAMPAGE
out (06h),a ;a=any valid RAM page number (83h-87h are unused by the OS
;see [[83Plus:OS:Ram Pages]] for more info on RAM pages
ldir
pop af
out (06h),a
ret</nowiki>

This routine is a modified version of the routine I use in my programs, and is untested, but seems like it would work. If there is anything I have forgotten PLEASE add it and tell me if possible.

--Nyquist562--

83Plus:BCALLs:42F1

2007-03-28T00:42:53Z

Nyquist562: Created a page for this bcall

[[Category:83Plus:BCALLs:By Name:Variable|ChkFindSym]] [[Category:83Plus:BCALLs:By Name|ChkFindSym]] [[Category:83Plus:BCALLs:By Address|42F1 - ChkFindSym]]
== Synopsis ==
'''Official Name:''' ChkFindSym

'''BCALL Address:''' 42F1

Recalls various pointers and information for a symbol in the VAT.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable (with proper initial defining byte, see example)

=== Outputs ===
* HL = VAT pointer
* DE = Data location (to the best of my knowledge, please confirm this)
* B = Flash Page, or 0 if in RAM
* C = Length of Varibale Name
* A = 'unknown'
* carry flag is set if the variable is not found in the VAT

=== Registers Destroyed ===
'All'

== Example ==
<nowiki>
ld hl,varname
B_CALL Mov9toOp1
B_CALL ChkFindSym
jr c,notfound ;cary flag is set if the VAT entry is not found
ex de,hl ;put data pointer into hl
xor a
cp b ;see if b is 0, and the program is in the ram
jr z,unarchived ;if so, jump to unarchived

;do something to get it into RAM

unarchived:

;do something once it is in RAM

varName:
.db AppVarObj, "APPVAR",0
</nowiki>

83Plus:BCALLs:4AE3

2007-03-28T00:32:27Z

Nyquist562: Moved to proper subcategory

[[Category:83Plus:BCALLs:By Name:Variable|RclVarSym]] [[Category:83Plus:BCALLs:By Name|RclVarSym]] [[Category:83Plus:BCALLs:By Address|4AE3 - RclVarSym]]
== Synopsis ==
'''Official Name:''' RclVarSym

'''BCALL Address:''' 4AE3

Recalls the value of a TI-OS variable.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable

=== Outputs ===
* [[83Plus:RAM:8478|OP1]] = Contents of Variable
* possibly others, please add if known

=== Registers Destroyed ===
''Unknown''

== Example ==
<nowiki>
B_CALL ZeroOP1 ;Reset OP1
ld hl,op1+1 ;have hl point to where the name should be stored
ld (hl),'H' ;load the name into op1+1
B_CALL RclVarSym ;store the value into op1 (in standard TI-OS floating point decimal form)</nowiki>

== Comments ==
This routine is used to recall TI-OS variables, such a 'A' or 'H' or other single letter varibales, but might be able to be used in recalling different types of variables. Once more doccumentation is found, it will be added.

83Plus:BCALLs:4AE3

2007-03-25T03:43:22Z

Nyquist562: Forgot to close parenthesis

[[Category:83Plus:BCALLs:By Name:Monitor|RclVarSym]] [[Category:83Plus:BCALLs:By Name|RclVarSym]] [[Category:83Plus:BCALLs:By Address|4AE3 - RclVarSym]]
== Synopsis ==
'''Official Name:''' RclVarSym

'''BCALL Address:''' 4AE3

Recalls the value of a TI-OS variable.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable

=== Outputs ===
* [[83Plus:RAM:8478|OP1]] = Contents of Variable
* possibly others, please add if known

=== Registers Destroyed ===
''Unknown''

== Example ==
<nowiki>
B_CALL ZeroOP1 ;Reset OP1
ld hl,op1+1 ;have hl point to where the name should be stored
ld (hl),'H' ;load the name into op1+1
B_CALL RclVarSym ;store the value into op1 (in standard TI-OS floating point decimal form)</nowiki>

== Comments ==
This routine is used to recall TI-OS variables, such a 'A' or 'H' or other single letter varibales, but might be able to be used in recalling different types of variables. Once more doccumentation is found, it will be added.

83Plus:BCALLs:4AE3

2007-03-25T03:42:53Z

Nyquist562: Added example

[[Category:83Plus:BCALLs:By Name:Monitor|RclVarSym]] [[Category:83Plus:BCALLs:By Name|RclVarSym]] [[Category:83Plus:BCALLs:By Address|4AE3 - RclVarSym]]
== Synopsis ==
'''Official Name:''' RclVarSym

'''BCALL Address:''' 4AE3

Recalls the value of a TI-OS variable.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable

=== Outputs ===
* [[83Plus:RAM:8478|OP1]] = Contents of Variable
* possibly others, please add if known

=== Registers Destroyed ===
''Unknown''

== Example ==
<nowiki>
B_CALL ZeroOP1 ;Reset OP1
ld hl,op1+1 ;have hl point to where the name should be stored
ld (hl),'H' ;load the name into op1+1
B_CALL RclVarSym ;store the value into op1 (in standard TI-OS floating point decimal form</nowiki>

== Comments ==
This routine is used to recall TI-OS variables, such a 'A' or 'H' or other single letter varibales, but might be able to be used in recalling different types of variables. Once more doccumentation is found, it will be added.

83Plus:BCALLs:4AEF

2007-03-25T03:37:15Z

Nyquist562: Created Page for this ROM call

[[Category:83Plus:BCALLs:By Name:Monitor|ConvOP1]] [[Category:83Plus:BCALLs:By Name|ConvOP1]] [[Category:83Plus:BCALLs:By Address|4AEF - ConvOP1]]
== Synopsis ==
'''Official Name:''' ConvOP1

'''BCALL Address:''' 4AEF

Converts a floating-point number in OP1 to a two-byte hexadecimal number in DE.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Floating Point Number in standard TI-OS decimal format.

=== Outputs ===
* A = Least SIgnificant Byte Value
* DE = Hex Value

=== Registers Destroyed ===
''Unknown''

== Comments ==
This information was supplimented by the Detatched Solutions forum site.
This routine is used to convert a floating-point number OP1 to a hex value in DE, but if the number in OP1 is greater than 9999, an error will occur. The same is thought to happen with decimal numbers; oince discovered, more doccumentation will appear on this ROM call.

83Plus:BCALLs:4AE3

2007-03-25T03:28:22Z

Nyquist562: Created page for this ROM call

[[Category:83Plus:BCALLs:By Name:Monitor|RclVarSym]] [[Category:83Plus:BCALLs:By Name|RclVarSym]] [[Category:83Plus:BCALLs:By Address|4AE3 - RclVarSym]]
== Synopsis ==
'''Official Name:''' RclVarSym

'''BCALL Address:''' 4AE3

Recalls the value of a TI-OS variable.

=== Inputs ===
* [[83Plus:RAM:8478|OP1]] = Name of variable

=== Outputs ===
* [[83Plus:RAM:8478|OP1]] = Contents of Variable
* possibly others, please add if known

=== Registers Destroyed ===
''Unknown''

== Comments ==
This routine is used to recall TI-OS variables, such a 'A' or 'H' or other single letter varibales, but might be able to be used in recalling different types of variables. Once more doccumentation is found, it will be added.

83Plus:BCALLs:4543

2007-03-25T02:33:58Z

Nyquist562: fixed function description

[[Category:83Plus:BCALLs:By_Name:Display|ClrLCD]] [[Category:83Plus:BCALLs:By_Name|ClrLCD]] [[Category:83Plus:BCALLs:By_Address|4543 - ClrLCD]]
== Synopsis ==
'''Official Name:''' ClrLCD

'''BCALL Address:''' 4543

Clears the non-graphing part of the screen, as opposed to its counterpart, ClrLCDFull, which clears the entire screen.

=== Inputs ===
* None

=== Outputs ===
* None

=== Destroys ===
* All

== Example ==
<nowiki>B_CALL _ClrLCD</nowiki>

83Plus:BCALLs:4543

2007-03-20T01:30:55Z

Nyquist562: Fixed Category

[[Category:83Plus:BCALLs:By_Name:Display|ClrLCD]] [[Category:83Plus:BCALLs:By_Name|ClrLCD]] [[Category:83Plus:BCALLs:By_Address|4543 - ClrLCD]]
== Synopsis ==
'''Official Name:''' ClrLCD

'''BCALL Address:''' 4543

Clears the display, ignoring any split-screen settings.

=== Inputs ===
* None

=== Outputs ===
* None

=== Destroys ===
* All

== Example ==
<nowiki>B_CALL _ClrLCD</nowiki>

== Comments ==
Indiscernible differences from ClrLCDFull

83Plus:BCALLs:4543

2007-03-20T01:29:22Z

Nyquist562: Created ClrLCD article

[[Category:83Plus:BCALLs:By_Name:Display|ClrLCD]] [[Category:83Plus:BCALLs:By_Name|ClrLCD]] [[Category:83Plus:BCALLs:By_Address|4543 - ClrLCDFull]]
== Synopsis ==
'''Official Name:''' ClrLCD

'''BCALL Address:''' 4543

Clears the display, ignoring any split-screen settings.

=== Inputs ===
* None

=== Outputs ===
* None

=== Destroys ===
* All

== Example ==
<nowiki>B_CALL _ClrLCD</nowiki>

== Comments ==
Indiscernible differences from ClrLCDFull

Category:83Plus:BCALLs:By Name:Utterly Useless

2007-03-20T01:14:58Z

Nyquist562: Added general info

[[Category:83Plus:BCALLs:By Name|Utterly Useless]]
These BCALLs almost serve a purpose, by giving us something to put in this section.

Experiments

2007-03-20T01:07:22Z

Nyquist562: Added another potential for experimentation

Here is a place for experiments, proof of concepts, surprising stuff made on TI-83(+):

* [http://www.ticalc.org/archives/files/fileinfo/368/36889.html QuadPlayer - Four channel sound] by Benryves : stereo sound with 4 tracks on TI-83(+)
* [http://www.revsoft.org/phpBB2/viewtopic.php?t=200 8bit/32khz sound] by Jim E on 84+SE.
* [http://www.ticalc.org/archives/files/fileinfo/341/34172.html 7-level greyscale]
* [http://clap.timendus.com/ CLAP - Linking more than two calculators]
* [[3D engines]]
* using LCD RAM as temporary RAM
* upgrading Calculator RAM
{{stub}}

83Plus:Basic:Graphics:Tangent(

2007-03-20T00:53:31Z

Nyquist562: closed parenthesis

[[Category:83Plus:Basic:Graphics|Tangent]]

== Synopsis ==
'''Token size:''' 1 byte

'''Syntax:''' Tangent(''function, x coordinate of tangency'')

Draws the tangent to a function at the specified x coordinate.

== Outputs: ==

''function'' is drawn on the graph screen, and the tangent line is drawn at the specified point.

== Examples ==
To draw the tangent to x^2-2 at x=1:
<nowiki>
ClrDraw
Tangent(x^2-2,1)</nowiki>

To draw the tangent to a function in the Y= menu at x=4:
<nowiki>
ClrDraw
Tangent(Y1,4)</nowiki>

83Plus:Basic:Graphics:Tangent(

2007-03-20T00:52:56Z

Nyquist562: Created an appropriate page for the Tangent function

[[Category:83Plus:Basic:Graphics|Tangent]]

== Synopsis ==
'''Token size:''' 1 byte

'''Syntax:''' Tangent(''function, x coordinate of tangency''

Draws the tangent to a function at the specified x coordinate.

== Outputs: ==

''function'' is drawn on the graph screen, and the tangent line is drawn at the specified point.

== Examples ==
To draw the tangent to x^2-2 at x=1:
<nowiki>
ClrDraw
Tangent(x^2-2,1)</nowiki>

To draw the tangent to a function in the Y= menu at x=4:
<nowiki>
ClrDraw
Tangent(Y1,4)</nowiki>

83Plus:Basic:Graphics:DrawInv

2007-03-20T00:46:20Z

Nyquist562: entered token size

[[Category:83Plus:Basic:Graphics|DrawInv]]

== Synopsis ==
'''Token size:''' 1 byte

'''Syntax:''' DrawInv ''function''

Draws the inverse of a function.

== Outputs: ==

The inverse of ''function'' (''function'' with the X and Y values switched) is drawn on the graph screen.

== Comments ==

*''function'' can be either a function specified directly (such as 3X^2) or one of the graph functions (such as Y3)

== Example ==

Draws a parabola starting at (0,0) and moving off to the right:

:DrawInv X^2

== See also: ==

[[83Plus:Basic:Graphics:DrawF|DrawF]]

83Plus:Basic:Graphics:Circle(

2007-03-20T00:45:58Z

Nyquist562: made Byte lower case

[[Category:83Plus:Basic:Graphics|Circle]]

== Synopsis ==
'''Token size:''' 1 byte

'''Syntax:''' Circle(''x coordinate, y coordinate, radius''

Draws a circle at the specified location, with coordiantes x,y at the vertex.

== Outputs: ==

A circle at x,y with a radius as specified.

== Example ==

Draws a circle starting at (2,-1) with a radius of 3:

:Circle(2,-1,3)

83Plus:Basic:Graphics:Circle(

2007-03-20T00:44:48Z

Nyquist562: Created an accurate page for the Circle Function

[[Category:83Plus:Basic:Graphics|Circle]]

== Synopsis ==
'''Token size:''' 1 Byte

'''Syntax:''' Circle(''x coordinate, y coordinate, radius''

Draws a circle at the specified location, with coordiantes x,y at the vertex.

== Outputs: ==

A circle at x,y with a radius as specified.

== Example ==

Draws a circle starting at (2,-1) with a radius of 3:

:Circle(2,-1,3)

83Plus:Ports:10

2007-03-20T00:12:28Z

Nyquist562: Added info about the TI84 plus

[[Category:83Plus:Ports:By Address|10 - LCD Command/Status Port]][[Category:83Plus:Ports:By Name|LCD Command/Status Port]]
== Synopsis ==
'''Port Number:''' 10h

'''Function:''' LCD Command and Status Port

This port is used to check the status of and send commands to the TI-83+'s LCD Driver.

=== Read Values ===
The state of the LCD can be determined by reading this port.
* Bit 0: Set if auto-increment mode (commands 05 and 07) is selected, reset if auto-decrement mode (commands 04 and 06) is selected.
* Bit 1: Set if auto-increment or auto-decrement will affect the current column, or reset if auto-increment/decrement will affect the current row.
* Bit 2, 3: Not used.
* Bit 4: Set if in reset state, reset if in operating state. (Whatever that means.)
* Bit 5: Set if the display is enabled. Reset if disabled. (Note: LCD is completely turned off via [[83Plus:Ports:03|Port 03h]].)
* Bit 6: Set if the LCD will transfer 8 bits at a time through [[83Plus:Ports:11|Port 11]]. Reset if the LCD will only trasfer 6 bits at a time.
* Bit 7: Set if the LCD is busy. Reset if a command can be accepted.

=== Write Values ===
Writing this port sends a command to the LCD. Once you send a command, wait until bit 7 reads 0 before sending another. You need a minimum delay of 10 microseconds (60 cycles of whatever else on the 6MHz TI-83+, or ~150 on a TI-83+ Silver or any TI-84+ when running in [[83Plus:Ports:20|fast mode]]).

* 00 : Switch to 6-bit mode. ([[83Plus:Ports:11|Port 11]] transfers 6-bits at a time.)
* 01 : Switch to 8-bit mode. ([[83Plus:Ports:11|Port 11]] transfers 8-bits at a time.)
* 02 : Disable the screen. This blanks the screen and disconnects the LCD RAM from the physical screen, thus allowing you to use the LCD RAM as extra saferam. (But accessing it is so horribly slow that you should only do this if the usual saferam areas aren't enough and you don't need to display anything.)
* 03 : Enable the screen. This resumes displaying the LCD's RAM contents to the physical screen. (So any garbage you put into LCD RAM while it was off will show up, so B_CALL ClrLCDFull before this!)
* 04 : Set X auto-decrement mode. Every read or write operation from the data port will cause the LCD's internal pointer to move up one row.
* 05 : Set X auto-increment mode. Every read or write operation from the data port will cause the LCD's internal pointer to move down one row. The TI-83+ expects the LCD to be in this mode for most display routines.
* 06 : Set Y auto-decrement mode. Every read or write operation from the data port will cause the LCD's internal pointer to move left one column.
* 07 : Set Y auto-increment mode. Every read or write operation from the data port will cause the LCD's internal pointer to move right one column.
* [08~0B]: Set power supply enhancement. You'd be well advised to just leave this alone.
* [10~13]: Set power supply level. You'd be well advised to just leave this alone.
* [14~17]: Undefined.
* [18]: Cancel test mode (see Comments).
* [19~1B]: Undefined.
* [1C~1F]: Enter test mode (see Comments).
* [20~2E]: Set column when in 8-bit mode (command 01).
* [20~33]: Set column when in 6-bit mode (command 00).
* [34~3F]: Undefined.
* [40~7F]: "Z addressing" (It just changed what phyiscal row the top row of RAM is displayed on. The LCD will wrap the bottom of it's RAM to the top of the screen as needed.)
* [80~BF]: Set row.
* [C0~FF]: Set contrast. (C0 is lowest. Note that there is a [[83Plus:RAM:8447|System RAM area (contrast)]] for this which will need to be updated if you want 2nd+Up/2nd+Down to change the contast as expected (instead of causing a sudden jump...).)

== Comments ==
As mentioned, a 10 microsecond delay is required after sending the command. TI provides a routine at 000B (use normal CALL, not BCALL) that will delay the required amount of time. (Because this was not originally an LCD delay routine, on OS's prior to 1.13, calling it destroys the zero flag.)

On older calculators, this code sequence should also provide sufficent delay while also preserving the zero flag:
<nowiki> push hl ;15
push de ;30
pop de ;44
pop hl ;58
nop ;62</nowiki>

But I would advise you actually make use of these waste cycles somehow (process a buffer or something).

On some newer calculators, a fixed delay can still be used in combination with slowing the CPU through port [[83Plus:Ports:20|20]] and/or adjusting ports [[83Plus:Ports:29|29]] and [[83Plus:Ports:2A|2A]]. However, a large number of calculators have been produced recently whose LCD drivers, for whatever reason, do not respond as quickly. For this reason, except where the speed loss is absolutely unacceptable (such as for grayscale display) fixed delays should '''not''' be used. Instead either use the routine at 000B, or poll this port or [[83Plus:Ports:02|port 2]] manually.

===Test mode===
This is a very dangerous mode. The first test mode command (1C~1F) causes the screen to receive an unusually high amount of energy. The result is that the screen seems to go blank, save for a single blue(!) line on the TI 83, but on the TI 84's, the entire screen turns blue! Each subsequent command adds more blue lines. After you've had your fill of blueness, exit test mode by sending a exit test mode command (18), which also sets the contrast to it's highest. Now why is it dangerous? Sure it looks cool to make a supposedly black and white LCD to display BLUE, but you are pumping so much energy through the LCD to get this effect that leaving it in this mode for too long can cause long-term damage. Ever left your monitor on for a day or two and forget to set a screen saver? Remember how when you turned it off a burnt image of your screen remained? Well that's what can happen if you leave test mode on for too long. Other possible side effects include "dead pixels" (pixels that stay off no matter what you do).

So don't use test mode okay? Just pretend you didn't hear about it...

== Example ==
Turn the LCD "off" and back "on".
<nowiki>ld a, 02h
out (10h), a
push hl ;Or do something else that takes ~60 TStates.
push de
pop de
pop hl
nop
inc a
out (10h), a</nowiki>

== See Also ==
* [[83Plus:Ports:11|Port 11]] - LCD Data Port
* [http://wikiti.denglend.net/stuff/t6a04.pdf LCD driver datasheet]