LPC MicrocontrollersのトピックLPC1788: USB D+ Line pull-down after 11us https://community.nxp.com/t5/LPC-Microcontrollers/LPC1788-USB-D-Line-pull-down-after-11us/m-p/946841#M37662 <HTML><HEAD></HEAD><BODY><P><SPAN style="color: #000000; background-color: #ffffff; font-weight: 200; font-size: 12.96px;">I would like more information about theUSB 2.0&nbsp; D-PLUS line on the NXP part number LPC1788 microcontroller. When we power up, the D+ line starts to go "tri-state", then after 11us, the D+ line is internally pull-down to ground.&nbsp; Why?</SPAN></P></BODY></HTML> Wed, 19 Jun 2019 17:23:19 GMT paul_shaffer 2019-06-19T17:23:19Z LPC1788: USB D+ Line pull-down after 11us https://community.nxp.com/t5/LPC-Microcontrollers/LPC1788-USB-D-Line-pull-down-after-11us/m-p/946841#M37662 <HTML><HEAD></HEAD><BODY><P><SPAN style="color: #000000; background-color: #ffffff; font-weight: 200; font-size: 12.96px;">I would like more information about theUSB 2.0&nbsp; D-PLUS line on the NXP part number LPC1788 microcontroller. When we power up, the D+ line starts to go "tri-state", then after 11us, the D+ line is internally pull-down to ground.&nbsp; Why?</SPAN></P></BODY></HTML> Wed, 19 Jun 2019 17:23:19 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC1788-USB-D-Line-pull-down-after-11us/m-p/946841#M37662 paul_shaffer 2019-06-19T17:23:19Z Re: LPC1788: USB D+ Line pull-down after 11us https://community.nxp.com/t5/LPC-Microcontrollers/LPC1788-USB-D-Line-pull-down-after-11us/m-p/946842#M37663 <HTML><HEAD></HEAD><BODY><P>Hi Paul,</P><P></P><P>In the LPC1788 the USB D+ is initially a GPIO pin, which after a reset is configured as an input. This will cause it to be at a high impedance. Once the usb is configured and the internal pull down is enabled you will see the change in state. However this&nbsp;behavior from its power on state to once the pins are configured should not impact your project.</P><P></P><P>If you have any further questions please dont hesitate to ask.</P><P></P><P>Hope this helps and have a great day!</P><P>Sabina</P></BODY></HTML> Wed, 19 Jun 2019 20:11:43 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC1788-USB-D-Line-pull-down-after-11us/m-p/946842#M37663 Sabina_Bruce 2019-06-19T20:11:43Z