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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>ADC0808 output is not stable</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/39209/adc0808-output-is-not-stable</link><description> 
Dear All, 
following is the code is not working..can any please guide me where
is the problem.. 
#include&amp;lt;reg51.h&amp;gt; 
sbit ale=P1^0; //address latch enable 
sbit oe=P1^3; //output enable 
sbit sc=P1^1; //start conversion 
sbit eoc=P1^2; //end of conversion</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/150780?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 08:09:17 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:bd331a3a-2ead-4594-9ed7-b398c3d74b3f</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
&amp;#39;u&amp;#39; is the symbol for &amp;quot;micro&amp;quot;&lt;/p&gt;

&lt;p&gt;
Why do you keep putting &amp;quot;micro&amp;quot; in your sentences?&lt;/p&gt;

&lt;p&gt;
Is it really too hard for you to write &amp;quot;you&amp;quot; ?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/145077?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 07:21:58 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:03503511-a50b-4b91-a603-43d7143c5c2a</guid><dc:creator>ansari rahim</dc:creator><description>&lt;p&gt;&lt;p&gt;
&amp;quot;maybe micro (u) can guide you as to what resist (r) that toggle
routine&amp;quot;&lt;br /&gt;
pls explain..i didnot get u.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/142864?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 07:18:03 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:863b67f3-b878-49c3-883b-d30e871a0107</guid><dc:creator>c51 adc0808</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;b&gt;my requirment is simple&lt;/b&gt;&lt;/p&gt;

&lt;p&gt;
LOL, how did YOU determine that?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/139873?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 07:01:45 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:fdb58490-cc80-4438-8416-6c88cc78d3c3</guid><dc:creator>&amp;#178;erik malund</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;what r that toggle routine of timers can u guide me ?&lt;/i&gt;&lt;br /&gt;
maybe micro (u) can guide you as to what resist (r) that toggle
routine&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/139870?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:58:09 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:53d007c7-2d70-4835-a596-4b56501a9711</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;quot;what r that toggle routine of timers can u guide me ?&amp;quot;&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
Study the &lt;b&gt;Datasheet&lt;/b&gt; for your 8051 chip!&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/139878?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:53:17 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:6f81db2e-55ea-4867-8c48-3bf114c50029</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
No, I can not guide you.&lt;/p&gt;

&lt;p&gt;
I did say _some_ 8051 timers can toggle pins.&lt;/p&gt;

&lt;p&gt;
I don&amp;#39;t know if you have any timers that do support this. But you
should be able to figure this out since you can read datasheets and
knows what chip you have.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/130770?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:40:31 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:f73cd048-7558-47e7-8b6f-0c2292c167aa</guid><dc:creator>ansari rahim</dc:creator><description>&lt;p&gt;&lt;p&gt;
what r that toggle routine of timers can u guide me ?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/126754?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:29:23 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:32fb9948-ef49-4649-ab21-aecb250d2027</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
Are you saying that you haven&amp;#39;t even checked if you do get a
500kHz signal generated from your ISR? You are not doing any
debugging at all - just moving the responsibility for thinking to
&amp;quot;the net&amp;quot;?&lt;/p&gt;

&lt;p&gt;
Why haven&amp;#39;t you bothered to return with real responses to my
initial post?&lt;/p&gt;

&lt;p&gt;
By the way - some 8051 timers can be used to directly toggle an
external pin, allowing programmable square wave output without any
ISR that performs the toggling.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/116303?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:09:24 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:2768b88a-59fe-42ff-a942-fc6123c29adf</guid><dc:creator>ansari rahim</dc:creator><description>&lt;p&gt;&lt;p&gt;
Yes, i read but i have data sheet for adc, and the first link i
did not understand what was that? As per code: there is no problem in
that code? is there any way to generate 500KHz pulses from MCU
AT89s8253? or pls suggest me any code to achieve this stuff...pls.
pls. pls&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/104723?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:02:22 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:440badbf-5ca2-406f-8717-1eb2113c39a5</guid><dc:creator>Tamiryan Michael</dc:creator><description>&lt;p&gt;&lt;p&gt;
Did you even READ the comments above?&lt;br /&gt;
Do you really understand what your code does? Do you understand that
this is a MUST in order for _your_ code to work?&lt;br /&gt;
Now, take a deep breath and explain, SLOWLY and clearly, exactly what
the problem is and what you have done so far.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/104727?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 06:02:12 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:6a057e77-308f-44fc-a763-05bdc8bc9a5f</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
What have you been doing in that week?&lt;/p&gt;

&lt;p&gt;
&lt;a href="http://www.lmgtfy.com?q=at89s8253+at89s8252+MCU+with+ADC0808"&gt;www.lmgtfy.com&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
&lt;a href="http://www.national.com/mpf/DC/ADC0808.html"&gt;www.national.com/.../ADC0808.html&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
Have you checked that the 500kHz clock is accurate &amp;amp;
stable?&lt;/p&gt;

&lt;p&gt;
Have you checked that the analogue input to the ADC is stable?
Obviously, if you have glitches on the analogue input, then you are
going to get glitches in the digital output!&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/104726?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 05:55:17 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:cf38d78c-02e8-4b45-b972-0b489f206c73</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;p&gt;
IF the &amp;quot;unexpected values&amp;quot; are coming from the outputs &lt;i&gt;of the
ADC&lt;/i&gt; then, surely, it&amp;#39;s nothing to do with the 8051 or the code
running on it?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/79169?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 05:55:04 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:b06415be-1791-489b-8e6c-9fb2dca5643f</guid><dc:creator>ansari rahim</dc:creator><description>&lt;p&gt;&lt;p&gt;
Further,&lt;br /&gt;
my requirment is simple..i want to run at89s8253/52 MCU with ADC0808
and i m giving 500KHz pulses as clock to ADC ..If any have code for
such hardware (AT89s8253,crystal 11.0592MHz and ADC0808) then pls pls
send me...i m fed up from one week ..&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/79168?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 05:48:51 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:7fad222d-f4c2-494d-aa72-70ead7bd0da8</guid><dc:creator>ansari rahim</dc:creator><description>&lt;p&gt;&lt;p&gt;
Dear Sir, i m getting unexpected values on D0-D7(outputs) of
ADC,even if my input analog is stable which is 0 to 5 volt and Ref.
voltage is +5Volt..i m trying to solve this problem from last one
week but i m getting unstable values from the mentioned code...pls
help me... if u have any source code to operate successfully ADC0808
then pls provide me ..it is very very very urgent....&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: ADC0808 output is not stable</title><link>https://community.arm.com/thread/66441?ContentTypeID=1</link><pubDate>Wed, 30 Mar 2011 05:34:59 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:b3b9ed6b-4e5b-405d-94c7-9afa6b1ab0b7</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
You have an interrrupt that is intended to run with 500kHz
frequency. Is your processor even fast enough to manage 0.5 million
interrupts / second - remember that every interrupt consumes several
instructions.&lt;/p&gt;

&lt;p&gt;
Why don&amp;#39;t you use a timer to create the 1ms delay? Don&amp;#39;t you
realize that the delay time of a software loop is affected by the
percentage of CPU capacity that is consumed by interrupts?&lt;/p&gt;

&lt;p&gt;
By the way - where is the source code? You don&amp;#39;t have anything
tagged as code in your post - didn&amp;#39;t you notice the information about
how to post source code?&lt;/p&gt;

&lt;p&gt;
What is wrong? You haven&amp;#39;t exactly spent much time explaining your
troubles. Just a subject line &amp;quot;ADC0808 output is not stable&amp;quot;. Nothing
about exactly what happens and what things you have done to try to
figure out what is wrong.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>