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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>RS485 with 89c51</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/21174/rs485-with-89c51</link><description> 
Hi everybody, 

 
I want to receive data from a Loadcell Indicator throughout RS485.
The LoadCell Indicator only send data to Micro chip. I also
want my Micro chip communicate with the computer in both ways
(transfer and receive) by RS232. 

 
Can I</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/74715?ContentTypeID=1</link><pubDate>Sun, 14 Jan 2007 07:16:31 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:33e11f68-d7c3-497d-9f51-781322081eaf</guid><dc:creator>Le Xuan Huy</dc:creator><description>&lt;p&gt;&lt;p&gt;
Dear Ali Karakas,&lt;/p&gt;

&lt;p&gt;
Thank you for your helps. I will remember your comment to use in
future. In this projects I already changed to use PSoC chip with 2
UARTs.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/47568?ContentTypeID=1</link><pubDate>Sun, 14 Jan 2007 06:55:31 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:ced0dcc5-1496-4b70-8256-c0ccf711f13a</guid><dc:creator>ali karakas</dc:creator><description>&lt;p&gt;&lt;p&gt;
You can use spesific RS485 IC for cominication. &amp;amp;#304;f yu can
use full-dublex IC and 4 wire interface this time RS232 and RS485 fou
you same way(beetwen 2 circuit). But if you can use in a RS485
network you must crate your own protocol for cominication.
&amp;amp;#304;f you can use onli 2 circuit its very easy.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/138349?ContentTypeID=1</link><pubDate>Fri, 12 Jan 2007 04:34:28 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:41f34ab4-3783-4bff-9b4c-03461f6c2c72</guid><dc:creator>Le Xuan Huy</dc:creator><description>&lt;p&gt;&lt;p&gt;
Thank you all for your comments.&lt;/p&gt;

&lt;p&gt;
Huy&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/134903?ContentTypeID=1</link><pubDate>Fri, 12 Jan 2007 01:51:27 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:7645fe75-bc07-4e48-9bd9-b420b3a40a21</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;quot;But I am student, I bought this chip so I have to use this
one.&amp;quot;&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
So, Hopefully, this is your first lesson learned: don&amp;#39;t buy the
chip until &lt;b&gt;after&lt;/b&gt; you have determined which chip you need!&lt;/p&gt;

&lt;p&gt;
As Erik said, this is a classic example of &amp;quot;putting the cart
before the horse&amp;quot;.&lt;/p&gt;

&lt;p&gt;
Anyhow, if you&amp;#39;re really stuck with it...&lt;/p&gt;

&lt;p&gt;
&lt;i&gt;&amp;quot;I think may be I can use another small chip to receive data
from LoadCell and pass it to main chip&amp;quot;&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
Yes, although that&amp;#39;s an extra cost - check carefully that it won&amp;#39;t
work out cheaper to just go and buy a 2-UART 8051!&lt;br /&gt;
And also consider your timescales to design it in - what is your
deadline?&lt;/p&gt;

&lt;p&gt;
You can get external UART chips with parallel interfaces and also
with SPI or I2C connections to the main processor.&lt;br /&gt;
You could even use a 2nd, small, cheap, microcontroller...&lt;/p&gt;

&lt;p&gt;
Again, there&amp;#39;s the soft-UART option...&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/123611?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 21:56:18 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:481f3286-d789-4784-9c24-b8a2f224b4d0</guid><dc:creator>Le Xuan Huy</dc:creator><description>&lt;p&gt;&lt;p&gt;
Thank you Sirs,&lt;/p&gt;

&lt;p&gt;
But I am student, I bought this chip so I have to use this one. I
think may be I can use another small chip to receive data from
LoadCell and pass it to main chip by P0 and P2. (Actually, the
loadcell has 19 bits, but I will cut 3 LSBs to get 16 bits)&lt;/p&gt;

&lt;p&gt;
(P1.3 is used to generate PWM, and P3.0 P3.1 are used for RS232 so
P0 and P2 are free)&lt;/p&gt;

&lt;p&gt;
May I do like that?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/123614?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 18:08:22 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:232a55f0-ffdc-4770-bcb6-851dd06f814c</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;quot;you post &amp;#39;89C51&amp;#39; which can be AT89C51, P89C51, something else
or a generic name.&amp;quot;&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
The title just said &amp;#39;89C51&amp;#39;, but the body of the post did specify
T89C51AC2.&lt;/p&gt;

&lt;p&gt;
:-)&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/112578?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 15:21:02 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:e167bda5-264d-4c5f-858c-2a6b4e0b774c</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;This is exactly my first project with Micro&lt;/i&gt; then i strongly
recommend that you buy a SILabs devboard (F0xx, f1xx, f2xx - stay
away from f3xx, f4xx and f5xx) it will give you ICE functionality
which gives yo the ability to see everything that goes on inside the
chip in real life, not &amp;#39;simulated&amp;#39;&lt;/p&gt;

&lt;p&gt;
one more hint&lt;/p&gt;

&lt;p&gt;
there is, here, the Keil device database&lt;/p&gt;

&lt;p&gt;
&lt;a href="http://www.keil.com/dd/parm_search.asp"&gt;http://www.keil.com/dd/parm_search.asp&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
it allow you to select 2 UARTs and get a list of all &amp;#39;51
derivatives with that.&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: RS485 with 89c51</title><link>https://community.arm.com/thread/98832?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 15:05:34 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c50e6c43-0298-4908-b184-f6356a718b77</guid><dc:creator>Le Xuan Huy</dc:creator><description>&lt;p&gt;&lt;p&gt;
Yeah, This is exactly my first project with Micro. For all
comments, I need time to understand them but I want to say thank you
to all for your helps.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/112575?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 15:04:59 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c823c133-b8ce-4b24-9440-c55b5b7f4084</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;p&gt;
you post &amp;#39;89C51&amp;#39; which can be AT89C51, P89C51, something else or a
generic name.&lt;/p&gt;

&lt;p&gt;
Ever so many posts have gone astray because the derivative name
was not totally clear.&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: RS485 with 89c51</title><link>https://community.arm.com/thread/98811?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 14:59:46 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c744880e-2555-41af-a0f5-0a26eddf32a3</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;Which begs the question: why choose a processor with only one
UART, when plenty are available with two (or even more!)&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
I can not count the posts I have seen over the years where the
derivative has been selected &amp;lt;b.before the application was
defined. Talk about &amp;quot;cart before the horse&amp;quot;&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: RS485 with 89c51</title><link>https://community.arm.com/thread/88121?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 14:53:56 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:574f1a08-d5d0-43a6-9853-a94373641528</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;quot;Looks like that microcontroller has one UART, so it won&amp;#39;t be
real straightforward&amp;quot;&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
Which begs the question: why choose a processor with only one
UART, when plenty are available with two (or even more!)&lt;/p&gt;

&lt;p&gt;
Why make life difficult for yourself - especially as this is your
first microcontroller project?!&lt;/p&gt;

&lt;p&gt;
It is possible to make a &lt;i&gt;software&lt;/i&gt; UART - or, in this case,
just a software receiver.&lt;br /&gt;
Search for &amp;quot;Soft UART&amp;quot; or &amp;quot;software UART&amp;quot; and &amp;quot;bit-bang&amp;quot;&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: RS485 with 89c51</title><link>https://community.arm.com/thread/50432?ContentTypeID=1</link><pubDate>Thu, 11 Jan 2007 14:30:55 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:ace8c94a-2282-4f56-9854-30c9c96d2b6f</guid><dc:creator>Dave Sudolcan</dc:creator><description>&lt;p&gt;&lt;p&gt;
Looks like that microcontroller has one UART, so it won&amp;#39;t be real
straightforward, but it should still be possible.&lt;/p&gt;

&lt;p&gt;
You&amp;#39;ll probably need to add some glue logic and an I/O pin or two
to switch your UART back and forth between the two ports. You&amp;#39;ll
probably need to add some kind of software logic to handle switching
to the RS485 port in the middle of receiving data from the load cell,
resulting in garbled data, which you&amp;#39;ll have to ignore and then wait
for good data to arrive.&lt;/p&gt;

&lt;p&gt;
If your PC initiates communication with your board, rather than
the other way around, trying to share one UART with both ports is a
little more trickier still. You&amp;#39;ll probably have to add some kind of
auto retry protocol to the RS232 port for the case when your PC tries
to talk to your board, but the UART&amp;#39;s connected to the RS485 port
instead.&lt;/p&gt;

&lt;p&gt;
Having an RS485 device that transmits only seems odd, as it
somewhat complicates having multiple devices on an RS485 bus, which
is normally a common thing to do.&lt;/p&gt;

&lt;p&gt;
Good luck !!&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>