<?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>I/O problem</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/14078/i-o-problem</link><description> Hi : 
 
I input a high signal (4V) from the output pin of 7832 (OR Gate) to the GPIO pin of 8051. 
I see the signal voltage is right on scope. 
But the fact is the 8051 can&amp;#39;t receive this signal. 
Why ? 
Is the current too small to start the GPIO ? </description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: I/O problem</title><link>https://community.arm.com/thread/53636?ContentTypeID=1</link><pubDate>Fri, 27 Apr 2001 03:58:07 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:d61aa2de-8ca3-4a10-be8d-87e68271329f</guid><dc:creator>HSU Yi</dc:creator><description>&lt;p&gt;This condition is as below:&lt;br /&gt;
I think the 8051 receivee the signal.&lt;br /&gt;
But my camera can&amp;#39;t work.&lt;br /&gt;
I inspect the noise of ground.&lt;br /&gt;
The noise is 500 mV.&lt;br /&gt;
My camera&amp;#39;s power supply is 3.3V.&lt;br /&gt;
So ..&lt;br /&gt;
Does anybody know whether it resulted &lt;br /&gt;
the camera can&amp;#39;t work ?&lt;br /&gt;
Thanks&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I/O problem</title><link>https://community.arm.com/thread/37442?ContentTypeID=1</link><pubDate>Fri, 27 Apr 2001 02:08:27 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c1c4fee6-464a-4bbf-ae6f-991d6545137b</guid><dc:creator>Paul Vermeer</dc:creator><description>&lt;p&gt;Do you have the pin set as input &lt;br /&gt;
(DDR set to 0)&lt;br /&gt;
Does this pin have an alternative mode ?&lt;br /&gt;
&lt;br /&gt;
If possible, advertise the piece of code on the forum. (summary !!)&lt;br /&gt;
&lt;br /&gt;
Best regards ...&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>