topic LPC1768 QEI max. frequency in LPC Microcontrollers https://community.nxp.com/t5/LPC-Microcontrollers/LPC1768-QEI-max-frequency/m-p/522791#M5427 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by yilmazkircicek on Fri May 02 00:15:30 MST 2014</STRONG><BR /><SPAN>Hi All,</SPAN><BR /><BR /><SPAN>We are testing encoder with</SPAN><STRONG> LPC1768</STRONG><SPAN> </SPAN><STRONG>QEI</STRONG><SPAN> module and experienced that we miss some of the pulses with inceasing rpm and encoder resolution.</SPAN><BR /><BR /><SPAN>For example: </SPAN><BR /><BR /><SPAN>Encoder with </SPAN><STRONG>40.000</STRONG><SPAN> pulse is turns&nbsp; </SPAN><STRONG>@3000 rpm</STRONG><SPAN>. This yields 40.000 * 3000 / 60 = </SPAN><STRONG>2 Mhz</STRONG><SPAN>. </SPAN><BR /><BR /><SPAN>When we turn it </SPAN><STRONG>10</STRONG><SPAN> times</SPAN><STRONG> @3000</STRONG><SPAN> rpm with a precision servo system, we count </SPAN><STRONG>399.9xx </STRONG><SPAN>instead of </SPAN><STRONG>400.000</STRONG><SPAN>. </SPAN><BR /><SPAN>It is ok when we slow down the servo to </SPAN><STRONG>1500rpm.</STRONG><BR /><BR /><SPAN>I know that the driver IC used in encoder has </SPAN><STRONG>2Mhz</STRONG><SPAN> band witdh and it is mostly related with it.</SPAN><BR /><BR /><SPAN>But I could not able to find max. speed of QEI module in documents. (while digital filter sampling delay = 0)</SPAN><BR /><SPAN>We are running the </SPAN><STRONG>LPC1768</STRONG><SPAN> and </SPAN><STRONG>QEI</STRONG><SPAN> peripheral&nbsp; </SPAN><STRONG>@100 Mhz</STRONG><SPAN>.</SPAN><BR /><BR /><SPAN>Could anyone tell me that what is the limiting speed for</SPAN><STRONG> QUI </STRONG><SPAN>module of </SPAN><STRONG>LPC1768</STRONG><SPAN> please ?</SPAN><BR /><BR /><SPAN>Best Regards.</SPAN><BR /><BR /></BODY></HTML> Wed, 15 Jun 2016 17:57:21 GMT lpcware 2016-06-15T17:57:21Z LPC1768 QEI max. frequency https://community.nxp.com/t5/LPC-Microcontrollers/LPC1768-QEI-max-frequency/m-p/522791#M5427 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by yilmazkircicek on Fri May 02 00:15:30 MST 2014</STRONG><BR /><SPAN>Hi All,</SPAN><BR /><BR /><SPAN>We are testing encoder with</SPAN><STRONG> LPC1768</STRONG><SPAN> </SPAN><STRONG>QEI</STRONG><SPAN> module and experienced that we miss some of the pulses with inceasing rpm and encoder resolution.</SPAN><BR /><BR /><SPAN>For example: </SPAN><BR /><BR /><SPAN>Encoder with </SPAN><STRONG>40.000</STRONG><SPAN> pulse is turns&nbsp; </SPAN><STRONG>@3000 rpm</STRONG><SPAN>. This yields 40.000 * 3000 / 60 = </SPAN><STRONG>2 Mhz</STRONG><SPAN>. </SPAN><BR /><BR /><SPAN>When we turn it </SPAN><STRONG>10</STRONG><SPAN> times</SPAN><STRONG> @3000</STRONG><SPAN> rpm with a precision servo system, we count </SPAN><STRONG>399.9xx </STRONG><SPAN>instead of </SPAN><STRONG>400.000</STRONG><SPAN>. </SPAN><BR /><SPAN>It is ok when we slow down the servo to </SPAN><STRONG>1500rpm.</STRONG><BR /><BR /><SPAN>I know that the driver IC used in encoder has </SPAN><STRONG>2Mhz</STRONG><SPAN> band witdh and it is mostly related with it.</SPAN><BR /><BR /><SPAN>But I could not able to find max. speed of QEI module in documents. (while digital filter sampling delay = 0)</SPAN><BR /><SPAN>We are running the </SPAN><STRONG>LPC1768</STRONG><SPAN> and </SPAN><STRONG>QEI</STRONG><SPAN> peripheral&nbsp; </SPAN><STRONG>@100 Mhz</STRONG><SPAN>.</SPAN><BR /><BR /><SPAN>Could anyone tell me that what is the limiting speed for</SPAN><STRONG> QUI </STRONG><SPAN>module of </SPAN><STRONG>LPC1768</STRONG><SPAN> please ?</SPAN><BR /><BR /><SPAN>Best Regards.</SPAN><BR /><BR /></BODY></HTML> Wed, 15 Jun 2016 17:57:21 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC1768-QEI-max-frequency/m-p/522791#M5427 lpcware 2016-06-15T17:57:21Z