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<?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>RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/25872/ri-receive-interrupt-flag-problem-in-scon-register-serial-communication</link><description> 
Hello, 
I need help with the serial communication, when I am sending data
from PC (hyper-terminal) through RS232 , RI flag should rise to &amp;#39;1&amp;#39;
and its does not happened, what may be the problem? 

 
BTW, when I am programming the same device in the PLCC</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/115982?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 04:37:25 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:8d7d506b-6845-405b-a7b1-e8a57743d216</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
No, not totally irrelevant. If the PC can receive serial data,
then its likely (but not certain) that the baudrate setting is
correct. And it&amp;#39;s likely (but not certain) that the logic levels used
by the processor is compatible with the logic levels used by the
RS232 tranceiver.&lt;/p&gt;

&lt;p&gt;
It is always good to measure the bit lengths with an oscilloscope
and not just settle for &amp;quot;it receives&amp;quot;. Having an 11.xxx crystal but
having software computing the baudrate for a 12MHz crystal would mean
that there is a baudrate error, but that both sides may manage to
communicate anyway. Different UART allows more or less baudrate
errors depending on how many samples they take during a bit, and how
many low or high samples they require before deciding if they
received a zero or a one.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/104205?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 04:05:15 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:3b6f9f27-5a51-4e13-8c2c-c9ab3ac6e7ba</guid><dc:creator>&amp;#178;erik malund</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;my pcb pinout schematic fine. when I am sending the data to the
PC its work well.&lt;/i&gt;&lt;br /&gt;
totally irrelevant, the path for data TO the PC is not the same as
data FROM the PC.&lt;/p&gt;

&lt;p&gt;
Erik&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/126361?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 03:31:03 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:3d938c0f-47ee-4d5c-83ca-4de5a53bcef6</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
But, if the serial data is arriving at that pin, you would not
just see a 5V voltage, would you?&lt;/p&gt;

&lt;p&gt;
What, exactly, do you see? Is it valid serial data?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/115987?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 03:21:43 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:e86798c5-4add-40f9-b637-b17d11685c42</guid><dc:creator>Maor Atias</dc:creator><description>&lt;p&gt;&lt;p&gt;
Yes I verified the connection on the processor.&lt;br /&gt;
checked with oscilloscope voltage level seems fine 5V..&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/104207?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 02:35:33 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:4f583103-9240-4f4c-8b65-69ac3e5d74be</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
So, you checked off two of my items - same crystal frequency and
correct baudrate to be able to send to the PC.&lt;/p&gt;

&lt;p&gt;
What about the other items I listed?&lt;/p&gt;

&lt;p&gt;
Knowing that the two packages have different pinouts isn&amp;#39;t the
same as having verified that the serial data signal is reaching the
correct pin on the processor, and with correct voltage levels and
timing. Have you used an oscilloscope and checked?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/78604?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 01:49:58 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:2c98a043-0567-4c3d-8851-b95d65d9e6c4</guid><dc:creator>Maor Atias</dc:creator><description>&lt;p&gt;&lt;p&gt;
I am using AT89C5130A uC..&lt;br /&gt;
I know that the pinout may be different , my pcb pinout schematic
fine. when I am sending the data to the PC its work well.&lt;br /&gt;
I am using the same oscillator (16MHz freq.).&lt;br /&gt;
maybe I also need to check TI flag ??&lt;br /&gt;
again sending from the uC to the PC works well!&lt;/p&gt;

&lt;p&gt;
thanks for your help!&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/65838?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 00:08:19 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:afe44486-ee91-4652-b435-7fa34cda5f88</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
Note that the pinouts of different packages are not necessarily
the same...&lt;/p&gt;

&lt;p&gt;
Also, you haven&amp;#39;t said what chip you&amp;#39;re using!&lt;/p&gt;

&lt;p&gt;
Are you sure that valid data is actually reaching the UART&amp;#39;s input
pin?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RI (Receive Interrupt) flag problem in SCON register (Serial Communication)</title><link>https://community.arm.com/thread/65839?ContentTypeID=1</link><pubDate>Wed, 01 Sep 2010 00:07:47 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:70bb2297-7aa1-40be-b8a4-a1002db47603</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
What debugging have you done?&lt;/p&gt;

&lt;p&gt;
- does the data arrive at the correct pin of the processor - maybe
CAD symbol is incorrect?&lt;br /&gt;
- does it have the correct voltage levels?&lt;br /&gt;
- does it have the correct baudrate - easy to check that the chip
sends with same baudrate as the PC.&lt;br /&gt;
- is hyperterminal configured to require hw handshake signals?&lt;br /&gt;
- are there any known differences between the two chips, besides the
package?&lt;br /&gt;
- both chips using same crystal frequency?&lt;br /&gt;
- does everything else work ok with the VQFP-based design?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>