https://community.nxp.com/t5/LPC-Microcontrollers/LPC81XM-ISP-RXD-Pin/m-p/1359264#M46844 <P>Hi</P> <P>I don't know where is the misunderstanding but both schematic and datasheet are correct.</P> <P>I checked datasheet, U0_RXD is pin 19</P> <P><A href="https://www.nxp.com.cn/docs/en/data-sheet/LPC81XM.pdf" target="_blank">https://www.nxp.com.cn/docs/en/data-sheet/LPC81XM.pdf</A></P> <P>In ISP mode, pin PIO0_0 is connected to function U0_RXD and pin PIO0_4 is connected to function U0_TXD on the USART0 block.</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_0-1634798807443.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159730iDE83545E817B22EC/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_0-1634798807443.png" alt="ZhangJennie_0-1634798807443.png" /></span></P> <P>&nbsp;</P> <P>In LPC812 MAX board, the connection is the same as schematic.</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_1-1634799055367.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159731i12755E40578FFA73/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_1-1634799055367.png" alt="ZhangJennie_1-1634799055367.png" /></span></P> <P>&nbsp;</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_2-1634799828366.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159732i01C0407ADB8FDB85/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_2-1634799828366.png" alt="ZhangJennie_2-1634799828366.png" /></span></P> <P>&nbsp;</P> <P>Have a nice day,</P> <P>Jun Zhang</P> Thu, 21 Oct 2021 07:28:42 GMT ZhangJennie 2021-10-21T07:28:42Z https://community.nxp.com/t5/LPC-Microcontrollers/LPC81XM-ISP-RXD-Pin/m-p/1358070#M46831 <P>The data sheet for LPC81x defines pin 19 "In ISP mode, this is the USART0 receive pin U0_RXD.<BR />In boundary scan mode: TDO (Test Data Out)"</P><P>But the schematic of LPC812MAX target RX is connected to pin 18.</P><P>What are the correct pins to connect the ISP UART to?</P> Tue, 19 Oct 2021 19:07:58 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC81XM-ISP-RXD-Pin/m-p/1358070#M46831 ductio_aj 2021-10-19T19:07:58Z https://community.nxp.com/t5/LPC-Microcontrollers/LPC81XM-ISP-RXD-Pin/m-p/1359264#M46844 <P>Hi</P> <P>I don't know where is the misunderstanding but both schematic and datasheet are correct.</P> <P>I checked datasheet, U0_RXD is pin 19</P> <P><A href="https://www.nxp.com.cn/docs/en/data-sheet/LPC81XM.pdf" target="_blank">https://www.nxp.com.cn/docs/en/data-sheet/LPC81XM.pdf</A></P> <P>In ISP mode, pin PIO0_0 is connected to function U0_RXD and pin PIO0_4 is connected to function U0_TXD on the USART0 block.</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_0-1634798807443.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159730iDE83545E817B22EC/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_0-1634798807443.png" alt="ZhangJennie_0-1634798807443.png" /></span></P> <P>&nbsp;</P> <P>In LPC812 MAX board, the connection is the same as schematic.</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_1-1634799055367.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159731i12755E40578FFA73/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_1-1634799055367.png" alt="ZhangJennie_1-1634799055367.png" /></span></P> <P>&nbsp;</P> <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="ZhangJennie_2-1634799828366.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/159732i01C0407ADB8FDB85/image-size/medium?v=v2&amp;px=400" role="button" title="ZhangJennie_2-1634799828366.png" alt="ZhangJennie_2-1634799828366.png" /></span></P> <P>&nbsp;</P> <P>Have a nice day,</P> <P>Jun Zhang</P> Thu, 21 Oct 2021 07:28:42 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC81XM-ISP-RXD-Pin/m-p/1359264#M46844 ZhangJennie 2021-10-21T07:28:42Z