Kinetis MicrocontrollersのトピックK51 as USB Device: how to NAK a USB IN https://community.nxp.com/t5/Kinetis-Microcontrollers/K51-as-USB-Device-how-to-NAK-a-USB-IN/m-p/676494#M41607 <HTML><HEAD></HEAD><BODY><P>USB 2.0 allows a Device to NAK a USB In request if it has no data to send. &nbsp;This is normal. &nbsp;We were using this on code that was originally developed on a TI Stellaris processor, then ported to the K51 when TI suddenly discontinued the Stellaris line.</P><P></P><P>Reviewing the K51 Sub-Family Reference Manual, I find no reference whatsoever to forcing a NAK condition. &nbsp;Reviewing the USB code, I find no reference whatsoever to NAK in Device mode.<BR /><BR />How do I force a NAK if I have nothing to send?</P></BODY></HTML> Wed, 28 Jun 2017 16:40:44 GMT johnstrohm 2017-06-28T16:40:44Z K51 as USB Device: how to NAK a USB IN https://community.nxp.com/t5/Kinetis-Microcontrollers/K51-as-USB-Device-how-to-NAK-a-USB-IN/m-p/676494#M41607 <HTML><HEAD></HEAD><BODY><P>USB 2.0 allows a Device to NAK a USB In request if it has no data to send. &nbsp;This is normal. &nbsp;We were using this on code that was originally developed on a TI Stellaris processor, then ported to the K51 when TI suddenly discontinued the Stellaris line.</P><P></P><P>Reviewing the K51 Sub-Family Reference Manual, I find no reference whatsoever to forcing a NAK condition. &nbsp;Reviewing the USB code, I find no reference whatsoever to NAK in Device mode.<BR /><BR />How do I force a NAK if I have nothing to send?</P></BODY></HTML> Wed, 28 Jun 2017 16:40:44 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K51-as-USB-Device-how-to-NAK-a-USB-IN/m-p/676494#M41607 johnstrohm 2017-06-28T16:40:44Z Re: K51 as USB Device: how to NAK a USB IN https://community.nxp.com/t5/Kinetis-Microcontrollers/K51-as-USB-Device-how-to-NAK-a-USB-IN/m-p/676495#M41608 <HTML><HEAD></HEAD><BODY><P>Hi</P><P></P><P>An endpoint automatically NAKs when it has no data waiting to be sent (in its BD). Therefore there is nothing that needs to be done/forced.</P><P></P><P>Regards</P><P></P><P>Mark</P></BODY></HTML> Wed, 28 Jun 2017 20:29:54 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K51-as-USB-Device-how-to-NAK-a-USB-IN/m-p/676495#M41608 mjbcswitzerland 2017-06-28T20:29:54Z