noah
/
tibasicc


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165
							<!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
  <meta http-equiv="Content-Type"
 content="text/html; charset=iso-8859-1">
  <meta name="GENERATOR"
 content="Mozilla/4.7 [en] (X11; I; Linux 2.4.0-test6 i586) [Netscape]">
  <title>TI-89 Link Protocol Guide - Screenshots</title>
</head>
<body bgcolor="#ffffe8">
<b>TI-89 Link Protocol Guide</b> - Screenshots
<center>
<h2>
<hr align="center">Screenshots</h2>
</center>
The TI-89's screenshot ability is "silent," which means that the
calculator
does not need to be put in a special mode. Screenshots can be taken any
time the calculator is ready to accept a keypress.
<p>The protocol used for getting a screenshot is shown below. For
information
on packet formats, <a href="packet.html">click here</a>.
<table bgcolor="#ffffff" border="1" cellspacing="0" width="92%">
  <tbody>
    <tr>
      <th bgcolor="#008800" width="7%"><font color="#ffffff">Step</font></th>
      <th colspan="3" bgcolor="#008800"><font color="#ffffff">Direction</font></th>
      <th bgcolor="#008800" width="80%"><font color="#ffffff">Packet</font></th>
    </tr>
    <tr>
      <td bgcolor="#ffffff" width="7%">
      <center>1&nbsp;</center>
      </td>
      <td rowspan="4">
      <center><img src="graphics/comp.gif" alt="Computer" align="bottom"
 border="0" height="33" width="30"></center>
      </td>
      <td bgcolor="#ffffff">
      <center><img src="graphics/right.gif" alt="===&gt;" align="bottom"
 border="0" height="13" width="22"></center>
      </td>
      <td rowspan="4" bgcolor="#ffffff">
      <center><img src="graphics/calc.gif" alt="Calculator"
 align="bottom" border="0" height="35" width="60"></center>
      </td>
      <td bgcolor="#ffffff" width="80%">SCR</td>
    </tr>
    <tr>
      <td bgcolor="#ffffff" width="7%">
      <center>2&nbsp;</center>
      </td>
      <td bgcolor="#ffffff">
      <center><img src="graphics/left.gif" alt="&lt;===" align="bottom"
 border="0" height="13" width="22"></center>
      </td>
      <td bgcolor="#ffffff" width="80%">ACK</td>
    </tr>
    <tr>
      <td bgcolor="#ffffff" width="7%">
      <center>3&nbsp;</center>
      </td>
      <td bgcolor="#ffffff">
      <center><img src="graphics/left.gif" alt="&lt;===" align="bottom"
 border="0" height="13" width="22"></center>
      </td>
      <td bgcolor="#ffffff" width="80%">DATA - Format described below.</td>
    </tr>
    <tr>
      <td bgcolor="#ffffff" width="7%">
      <center>4&nbsp;</center>
      </td>
      <td bgcolor="#ffffff">
      <center><img src="graphics/right.gif" alt="===&gt;" align="bottom"
 border="0" height="13" width="22"></center>
      </td>
      <td bgcolor="#ffffff" width="80%">ACK</td>
    </tr>
  </tbody>
</table>
</p>
<p>The data packet contains a 3840-byte monochrome bitmap (1 bit per
pixel).
Each bit has a value of 1 if the corresponding pixel is dark or a value
of 0 if the corresponding pixel is light.
</p>
<p>The pixel order is left-to-right, then top-to-bottom (See figure
below).
<br>
Byte 0 defines the first 8 pixels in the left side of the top row of
the screen. Bytes 1-29 define the rest of the first row, bytes 30-59
define
the second row, etc.
</p>
<p><u>Example:</u>
<table border="0" cellspacing="0" width="100%">
  <tbody>
    <tr>
      <td bgcolor="#ccffcc">PC:</td>
      <td bgcolor="#ccffcc" width="50%"><b><tt>08 6D 00 00</tt></b></td>
      <td bgcolor="#ccffcc" width="50%"><i>Screenshot request</i></td>
    </tr>
    <tr>
      <td bgcolor="#ffcccc">TI:</td>
      <td bgcolor="#ffcccc" width="50%"><b><tt>98 56 00 00</tt></b></td>
      <td bgcolor="#ffcccc" width="50%"><i>Acknowledgement of request</i></td>
    </tr>
    <tr>
      <td bgcolor="#ffcccc">&nbsp;</td>
      <td bgcolor="#ffcccc" width="50%"><b><tt>98 15 00 0F </tt></b>&lt;3840
bytes plus 2 byte checksum&gt;</td>
      <td bgcolor="#ffcccc" width="50%"><i>Screen data</i></td>
    </tr>
    <tr>
      <td bgcolor="#ccffcc">PC:</td>
      <td bgcolor="#ccffcc" width="50%"><b><tt>08 56 00 00</tt></b></td>
      <td bgcolor="#ccffcc" width="50%"><i>Acknowledgement of data</i></td>
    </tr>
  </tbody>
</table>
</p>
<p>The following figure demonstrates byte ordering of the pixels if the
bitmap is in a 3840-element array data[]:
</p>
<p><img src="graphics/scrnshot.gif" alt="[pixel grid diagram]"
 align="bottom" border="0" height="467" width="776"></p>
<p>Remark: contrary to the TI92/92+ calculator, only the 160x100 upper
rectangle is visible on the TI89. The remaining bytes are usable (in
assembler
for instance) but they are not visible. So, a clipping is necessary
once
the screenshot have been got.
</p>
<p>Note that this format is different from the standard Windows bitmap
format, which specifies a value of 1 if the pixel is light and
bottom-to-top
row order.
<br>
&nbsp;
<table border="0" cellspacing="0" width="100%">
  <tbody>
    <tr>
      <td width="32%">
      <center><a href="packet.html"><img src="graphics/prevpage.gif"
 alt="[previous page]" align="bottom" border="2" height="32" width="32"></a><br>
      <a href="packet.html">Packet Formats</a></center>
      </td>
      <td width="34%">
      <center><a href="index.html"><img src="graphics/home.gif"
 alt="[home]" align="bottom" border="2" height="32" width="32"></a><br>
      <a href="index.html">Table of Contents</a></center>
      </td>
      <td width="34%">
      <center><a href="manual.html"><img src="graphics/nextpage.gif"
 alt="[next page]" align="bottom" border="2" height="32" width="32"></a><br>
      <a href="manual.html">Manual Transfers</a></center>
      </td>
    </tr>
  </tbody>
</table>
</p>
<hr align="center"><i>Site maintained by Romain Li&eacute;vin (<a
 href="mailto:roms@lpg.ticalc.org">roms@lpg.ticalc.org</a>)
and Tim Singer (<a href="mailto:tsinger@gladstone.uoregon.edu">tsinger@gladstone.uoregon.edu</a>)</i>
</body>
</html>