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# $Id: README.Drivers,v 1.4 2001/03/09 13:08:11 ltoetsch Exp $
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How to write new display drivers for lcd4linux

If you plan to write a new display driver for lcd4linux, you should follow
this guidelines:

* use Skeleton.c as a start point.
  You might also have a look at Text.c

* create a new sourcefile <drivername>.c and add it to the bottom of
  Makefile.am

* add an entry to configure.in

* there's no need for a <drivername>.h

* create one (or more) unique display names (your driver will be selected by
  this name in the 'Display'-line of lcd4linux.conf).

* include "display.h" in your driver, to get the LCD structure and various 
  BAR_ definitions

* include "cfg.h" if you need to access settings in the config file.

* create a LCD table at the bottom of your driver, and fill it with the
  appropriate values. Take care that you specify the correct bar capabilities
  of your display or driver:

  BAR_L:  horizontal bars headed left
  BAR_R:  horizontal bars headed right
  BAR_H2: driver supports horizontal dual-bars
  BAR_U:  vertical bars bottom-up
  BAR_D:  vertical bars top-down
  BAR_V2: driver supports vertical dual-bars

* edit display.c and create a reference to your LCD table:

     external LCD YourDriver[];

* extend the FAMILY table in display.c with your driver:

     FAMILY Driver[] = {
       { "Skeleton",      Skeleton },
       { "MatrixOrbital", MatrixOrbital },
       { "YourFamily",    YourDriver },
       { "" }
     };

* write the correspondig init(), clear(), put(), bar(), quit() and
  flush()-functions. There's no need to use a framebuffer and display its
  contents with the flush()- call (as in MatrixOrbital.c), you can directly
  write to the display in the put()- and bar()-functions, and use an empty
  flush()-function. But if you have a limited number of user-defined
  characters, and therefore you have to do some sort of 'character reduction'
  or similar stuff, you will have to use a framebuffer and the flush()-call. 
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<div class='path'>path: <a href='/lcd4linux.git/log/?id=22169050ad234f868ff030d49964673e0a5ba8b1&amp;showmsg=1&amp;follow=1'>root</a>/<a href='/lcd4linux.git/log/plugin_button_exec.c?id=22169050ad234f868ff030d49964673e0a5ba8b1&amp;showmsg=1&amp;follow=1'>plugin_button_exec.c</a> (<a href='/lcd4linux.git/log/plugin_button_exec.c?id=22169050ad234f868ff030d49964673e0a5ba8b1&amp;showmsg=1'>unfollow</a>)</div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/lcd4linux.git/log/plugin_button_exec.c?id=22169050ad234f868ff030d49964673e0a5ba8b1&amp;follow=1'>Collapse</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr class='logheader'><td><span title='2011-07-27 02:20:51 +0000'>2011-07-27</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/drv_st2205.c?id=0fe9009287dfe71ba74df0793b874fd47a2df525&amp;follow=1'>st2205-width-height-swap.patch from Hans de Goede</a></td><td>michael</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+2</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1147 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-07-27 02:19:58 +0000'>2011-07-27</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/plugin_i2c_sensors.c?id=f86dd50a614e0666e2c61331bee684d1a519562b&amp;follow=1'>hwmon patch from Hans de Goede</a></td><td>michael</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+14</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1146 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-07-27 02:14:11 +0000'>2011-07-27</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/drv_MatrixOrbital.c?id=1d611354c3a8bf7de4c487fe4af7f72778035477&amp;follow=1'>patch to support SureElectronicsDE-LD023 from Matt Joice</a></td><td>michael</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+16</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1145 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-05-06 18:21:47 +0000'>2011-05-06</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/drv_GLCD2USB.c?id=7fc8ef21bd019295cd73c9d805af727083dcc2be&amp;follow=1'>Fixed keypad widget in GLCD2USB</a></td><td>harbaum</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+7</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1144 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-02-12 22:46:19 +0000'>2011-02-12</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.c?id=f17287509f698f21f38ae047a306ddca3fc13140&amp;follow=1'>timer.c: fixed detection of positive clock skew (and some typos)</a></td><td>mzuther</td><td>4</td><td><span class='deletions'>-10</span>/<span class='insertions'>+10</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1143 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-23 22:45:46 +0000'>2011-01-23</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.c?id=5e69b1e3961ee896d44107c05650c915d9b24298&amp;follow=1'>timer.c: fixed clock skew detection</a></td><td>mzuther</td><td>1</td><td><span class='deletions'>-26</span>/<span class='insertions'>+46</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1142 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-23 17:01:08 +0000'>2011-01-23</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.c?id=c15760b9e502d12e4905ef898e9694436ec3bde3&amp;follow=1'>timer.c: skip intermediate timer intervals</a></td><td>mzuther</td><td>2</td><td><span class='deletions'>-16</span>/<span class='insertions'>+46</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
"timer_inc()" now checks how many trigger intervals have passed since
a given timer has been updated.  This might be due to "negative clock
skew" (think of summer time) or the fact that some processing took too
long (i.e. fetching of a web site).  These missed trigger intervals
are then skipped and the user is notified so that he may adapt his
timer settings.  This handling is essential, otherwise unprocessed
timers might stack up and would trigger continuously while at the same
time becoming notoriously late and unreliable.


git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1141 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-05 03:49:07 +0000'>2011-01-05</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/drv_MatrixOrbital.c?id=72e1f7501bd6806022b7a33e1424ea2cc7fa4059&amp;follow=1'>fix for a bug introduced in the DE-LD021 driver</a></td><td>michael</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+3</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1140 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-04 01:58:59 +0000'>2011-01-04</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.c?id=f95cad51ea998c6febe30b9da74bd2852449d3c1&amp;follow=1'>indentation</a></td><td>michael</td><td>2</td><td><span class='deletions'>-3</span>/<span class='insertions'>+3</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1139 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-04 01:58:25 +0000'>2011-01-04</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/drv_MatrixOrbital.c?id=0da867144a9cc418a2311efa816efcbdef7df70a&amp;follow=1'>support for Sure Electronics DE-LD021 by Natanael Olaiz</a></td><td>michael</td><td>1</td><td><span class='deletions'>-10</span>/<span class='insertions'>+8</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1138 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2011-01-02 00:39:10 +0000'>2011-01-02</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/smoketest.sh?id=8dd087e587f0a84ab9b30965d085e65efdb57715&amp;follow=1'>driver for EFN LED modules by Tilman Glötzner</a></td><td>michael</td><td>9</td><td><span class='deletions'>-21</span>/<span class='insertions'>+469</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1137 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2010-11-28 16:07:16 +0000'>2010-11-28</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer_group.h?id=475fdb43971a24c01db6d8bf5cb4351eb6b76cfe&amp;follow=1'>commented, corrected and beautified both timer and timer group code</a></td><td>mzuther</td><td>11</td><td><span class='deletions'>-197</span>/<span class='insertions'>+511</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1136 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2010-11-27 14:35:10 +0000'>2010-11-27</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.h?id=00db296b07befe1b511af73b00303c536cea0c6c&amp;follow=1'>finished commenting the timer code</a></td><td>mzuther</td><td>2</td><td><span class='deletions'>-46</span>/<span class='insertions'>+138</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1135 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2010-11-20 20:22:05 +0000'>2010-11-20</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/timer.h?id=20e4961f9eb3ea712a4d101d5984a6e0e68a23bd&amp;follow=1'>started commenting the timer code</a></td><td>mzuther</td><td>5</td><td><span class='deletions'>-52</span>/<span class='insertions'>+170</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
I'm not done yet, but my system is currently very unstable, and I
don't want the changes to get lost... :(


git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1134 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>
<tr class='logheader'><td><span title='2010-11-19 09:02:34 +0000'>2010-11-19</span></td><td class='logsubject'><a href='/lcd4linux.git/commit/lcd4linux.conf.sample?id=4447e1d46ca5cdb1839c9ece0426fd26db1b2817&amp;follow=1'>Added brightness support for GLCD2USB</a></td><td>harbaum</td><td>5</td><td><span class='deletions'>-28</span>/<span class='insertions'>+8014</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1133 3ae390bd-cb1e-0410-b409-cd5a39f66f1f


</td></tr>