<?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>communication with GSM</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/42571/communication-with-gsm</link><description> Hi all friends. 
I use LPC935 for my project and the powersupply for this type is 3.3V. I want to communicate with GSM phone trough UART at 115200b/s with internal RC oscillator @7.373Mhz.The BRGR0 and BRGR1 values are set for 115200b/s(BRGR0=0x30 and</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: communication with GSM</title><link>https://community.arm.com/thread/97073?ContentTypeID=1</link><pubDate>Mon, 18 Apr 2005 15:12:15 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:acb4f67b-7712-4ea6-b3dd-a80610c7273a</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;i&gt;I use RS-232 tranciver only for the communication with the PC. As i could read the manual of the GSM the signal required for the communication is TTL which is around 5V, correct me if im wrong. So is there a way to convert 3.3 output of the LPC935 to 5V without using a transistor with a resistor?&lt;/i&gt;&lt;br /&gt;
74HCT vith Vcc = 5V is 3.3 in and 5V out.&lt;br /&gt;
&lt;br /&gt;
Erik&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: communication with GSM</title><link>https://community.arm.com/thread/73158?ContentTypeID=1</link><pubDate>Mon, 18 Apr 2005 14:08:30 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:5da64163-c188-4f19-bd27-5c77923148ac</guid><dc:creator>Embeded NL</dc:creator><description>&lt;p&gt;Thank you for the reply.&lt;br /&gt;
I use RS-232 tranciver only for the communication with the PC. As i could read the manual of the GSM the signal required for the communication is TTL which is around 5V, correct me if im wrong. So is there a way to convert 3.3 output of the LPC935 to 5V without using a transistor with a resistor?&lt;br /&gt;
Best wishes&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: communication with GSM</title><link>https://community.arm.com/thread/87180?ContentTypeID=1</link><pubDate>Mon, 18 Apr 2005 12:05:36 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:7b8162ed-ca39-4dc6-9816-45f88c000e22</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;i&gt;When same data is sent trough a datacable from the PC, the phone responds correctly.&lt;/i&gt;&lt;br /&gt;
So, the thing respond to RS232 levels&lt;br /&gt;
&lt;i&gt; My question is whether the signal of the TxD of the LPC935 is not high enough to be able to communicate with the GSM. Do i need to put a pull-up or pull-down resistor or do i have to do something else. Im stuck and really need yours help.&lt;/i&gt;&lt;br /&gt;
CONFOUND IT, you need to &amp;quot;do something else&amp;quot; install a RS232 transciever!!!!!!!!.&lt;br /&gt;
&lt;br /&gt;
If you decide to post again under another name, you WILL get the same answer.&lt;br /&gt;
&lt;br /&gt;
Erik&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: communication with GSM</title><link>https://community.arm.com/thread/43860?ContentTypeID=1</link><pubDate>Mon, 18 Apr 2005 11:35:06 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:e9cfbaba-8c03-4f26-a289-cb462f26b062</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;&lt;i&gt;&amp;quot;My question is whether the signal of the TxD of the LPC935 is not high enough to be able to communicate with the GSM&amp;quot;&lt;/i&gt;&lt;br /&gt;
&lt;br /&gt;
What does the &lt;b&gt;Manual&lt;/b&gt; say?&lt;br /&gt;
&lt;br /&gt;
&lt;b&gt;Beware:&lt;/b&gt; some GSM modules use &amp;quot;unusual&amp;quot; voltages like 4.2V - you really must &lt;b&gt;read the manual&lt;/b&gt; carefully, and design accordingly.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: communication with GSM</title><link>https://community.arm.com/thread/43864?ContentTypeID=1</link><pubDate>Mon, 18 Apr 2005 09:28:29 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:b1ff0d52-e1ab-434a-96e4-77f913d59ee2</guid><dc:creator>Matthias Hertel</dc:creator><description>&lt;p&gt;Are you using an RS232 tranceiver device?&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>