JTAG connector

cde1cde1 New Member Posts: 15
So I'd like to debug the Linux kernel, and there seems to be a 10-pin JTAG/SWD connector right behind the USB ports. It this the case? If so, it'd be great to know the compatibility with ots jtag debuggers (J-Link, FTDI-based, also Trace32). In addition OpenOCD and/or T32 scripts would be very welcome.


  • [Deleted User][Deleted User] Posts: 0 mod
    it is not a JTAG port, it is a UART-debug port (1.8V) connected to CPU but we don't sell any cable for the moment (could be done in the future if there will be more people asking)
  • cde1cde1 New Member Posts: 15
    edited July 2016
    Thanks. So is it like uart2? With uart0 on the CN7 and uart1 on the 40-pin GP-bus. Also, is it possible maybe to provide the pinout for this debug UART? I already have a cable that fits as well as a 1.8V ftdi cable.

    EDIT: after looking at the UP Connectors Description document, it appears this is indeed a JTAG header and not an uart. I was mistaken, this is a 12-pin instead of 10-pin connector. The doc says CN34 is "Update CPLD Header", so I'm unsure about its purpose. Is there a CPLD/FPGA on the board? I'm thinking this JTAG access, in addition to debugging the kernel, could be used in the case of a BIOS brick.
  • [Deleted User][Deleted User] Posts: 0 mod
    CN7 has 2x USB2 port and 1xUART-debug port for BIOS debug (you can find the pinout in "TOPIC: CN7 - 1x10P Wafer"
    CN34 has CPLD-JTAG port to upload CPLD-fw by cable; You cannot use this port as this will damage the board; this connector has FAN-pwr/ctrl as well.
  • cde1cde1 New Member Posts: 15
    Thanks aaeon. I probably won't be flashing the CPLD anyway.

    What about the second JTAG on the same header? I'm referring to CHT_GPIO_TMS/TDI/TCK/TDO. Does CHT means "chipset", and if correct could it be used to debug the SoC?
Sign In or Register to comment.