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Make the sed1520 driver work in 80-family connection style without requiring

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an external inverter.
This commit is contained in:
mmdolze
2011-12-29 17:00:49 +00:00
parent cd22706496
commit 1d47d3abc3
4 changed files with 79 additions and 35 deletions
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docs/lcdproc-user/drivers/sed1520.docbook
+21 -17
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@@ -48,11 +48,12 @@ without having a datasheet to check against!</para>
<sect3 id="sed1520-80">
<title>80-style connection style</title>
<para>This mode of operation is selected if the RESET line is wired to ground.
The wiring used by this driver in 80-style mode requires the use of an external
74HC04 inverter and assumes you have /CS1 and /CS2 lines available (thus you
must have an external clock generator) and toggles the /RW line. This is the
original wiring by Robin Adams.</para>
<para>This mode of operation is selected if the RESET line is wired to
ground. The wiring used by this driver in 80-style mode assumes you have
/CS1 and /CS2 lines available (thus you must have an external clock
generator) and toggles the /RW line. This is the original wiring by Robin Adams
(<ulink url="http://www.usblcd.de/lcdproc/sed1520.php4">SED1520 LPT Port</ulink>).
</para>
<table id="sed1520-connections-80-mapping">
<title>SED1520 80-style wiring schematic</title>
@@ -214,14 +215,6 @@ line. Writing is controlled by toggling the E1 and E2 line while /RW is low.
</tgroup>
</table>
<note>
<para>This is the only wiring I was able to test. My display (Crystalfontz
CFAG12232J-TFH-TA) has E1 and E2 lines. Trying to use it with 80-style wiring
was not successful. I suspect that (as the E# line is used as /RD line in
80-style mode) the wiring resulted in reading from one chip while writing to
the other at the same time and the data bus got fuzzed.</para>
</note>
</sect3>
</sect2>
@@ -257,10 +250,11 @@ the other at the same time and the data bus got fuzzed.</para>
the level of the RESET line: 68-style MCU interface (high level) or
80-style MCU interface (low level).
</para><para>
Use value <literal>68</literal> if your display is connected 68-style
style. In this mode the E1 and E2 lines are cycled to write the data. If
you use <literal>80</literal> (the default), 80-style style is selected
and the /WR line is cycled and /CS1 and /CS2 lines are required.
Use value <literal>68</literal> if your display is connected using
&quot;68 family MPU&quot; style. In this mode E1 and E2 lines are cycled to
write the data. If you use <literal>80</literal> (the default),
&quot;80 family MPU&quot; style is selected and the /WR line is cycled and
/CS1 and /CS2 lines are required.
</para></listitem>
</varlistentry>
@@ -276,6 +270,16 @@ the other at the same time and the data bus got fuzzed.</para>
lot, larger value should likely be avoided.
</para></listitem>
</varlistentry>
<varlistentry>
<term>
<property>haveInverter</property> = &parameters.yesdefno;
</term>
<listitem><para>
The original wiring by Robin used an inverter to drive the control lines.
If you do not use an inverter set this to <literal>no</literal>.
</para></listitem>
</varlistentry>
</variablelist>
</sect3>