https://community.nxp.com/t5/Kinetis-Microcontrollers/JTAG-read-IDCODE/m-p/1626381#M64904 <P>On frdm-kl46z board I am trying to do jtag acces to K20DX128 via connector J14 "OpenSDA INTERFACE JTAG CONNECTOR".</P><P>I can read IDCODE when K20DX128 is kept under reset with SDA_RST_B signal is low.</P><P>When K20DX128 is powered up TDO is all zero.</P><P>Is IDCODE can only be read under reset state?</P><P>Note: K20DX128 runs <A href="https://github.com/ARMmbed/DAPLink/blob/main/source/hic_hal/freescale/k20dx/gcc/startup_MK20D5.S" target="_blank" rel="noopener">https://github.com/ARMmbed/DAPLink/blob/main/source/hic_hal/freescale/k20dx/gcc/startup_MK20D5.S</A> and in main only an empty while loop</P> Sat, 01 Apr 2023 12:48:00 GMT afs2023 2023-04-01T12:48:00Z https://community.nxp.com/t5/Kinetis-Microcontrollers/JTAG-read-IDCODE/m-p/1626381#M64904 <P>On frdm-kl46z board I am trying to do jtag acces to K20DX128 via connector J14 "OpenSDA INTERFACE JTAG CONNECTOR".</P><P>I can read IDCODE when K20DX128 is kept under reset with SDA_RST_B signal is low.</P><P>When K20DX128 is powered up TDO is all zero.</P><P>Is IDCODE can only be read under reset state?</P><P>Note: K20DX128 runs <A href="https://github.com/ARMmbed/DAPLink/blob/main/source/hic_hal/freescale/k20dx/gcc/startup_MK20D5.S" target="_blank" rel="noopener">https://github.com/ARMmbed/DAPLink/blob/main/source/hic_hal/freescale/k20dx/gcc/startup_MK20D5.S</A> and in main only an empty while loop</P> Sat, 01 Apr 2023 12:48:00 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/JTAG-read-IDCODE/m-p/1626381#M64904 afs2023 2023-04-01T12:48:00Z