<?xml version="1.0" encoding="UTF-8" ?>
<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>LPC1788 LCD EMC SDRAM Conflict</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/35857/lpc1788-lcd-emc-sdram-conflict</link><description> 
I encountered a strange problem on my Lpc1788 evaluation board. If
i turn off the LCD controller, the SDRAM works fine, it can pass any
testing. but if i turn on the LCD controller, SDRAM cannot pass
testing. 
i test the SDRAM by writing (char)0x12</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: LPC1788 LCD EMC SDRAM Conflict</title><link>https://community.arm.com/thread/83435?ContentTypeID=1</link><pubDate>Sun, 11 Dec 2016 18:34:26 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:b4cbe4fe-0a50-4ed0-ab02-ebcc850d5fa5</guid><dc:creator>HD Yang</dc:creator><description>&lt;p&gt;&lt;p&gt;
thanks very much for your reply.&lt;br /&gt;
I followed your advice and did more testing on the SDRAM.&lt;br /&gt;
Writing and Reading of the SDRAM in char mode did fail in several
addresses even with the LCD&lt;br /&gt;
controller turned off. so it looks like the problem is in the
SDRAM.&lt;br /&gt;
However, testing in short mode and int mode can still pass.&lt;br /&gt;
what could cause the SDRAM to fail in writing or reading char?&lt;br /&gt;
this problem is driving me crazy... this is the first time i&amp;#39;m using
SDRAM...&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: LPC1788 LCD EMC SDRAM Conflict</title><link>https://community.arm.com/thread/69726?ContentTypeID=1</link><pubDate>Fri, 09 Dec 2016 01:09:26 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:befe2299-a9a1-45d7-bece-b5c0947410b6</guid><dc:creator>edPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
What happens if you test with 0x1312?&lt;/p&gt;

&lt;p&gt;
And what happens if you fill a block with 0x01, 0x02, 0x03, 0x04,
... and then reads back the block?&lt;/p&gt;

&lt;p&gt;
Note that it isn&amp;#39;t uncommon that tests of external memory can give
&amp;quot;expected&amp;quot; results even when the memory isn&amp;#39;t enabled - the data is
written to the processor pins and the pins then manages to retain
that state for long enough that a read detects the same pattern. So
to test memory, it&amp;#39;s important to write varying data to multiple
memory addresses and then read back all addresses and check that each
of them have the expected content. Only then have you tested that an
actual memory stores data and that it isn&amp;#39;t the port pin capacitances
that stores the last write.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>