[SOLVED] J-Link CJTAG short connect sequence

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  • [SOLVED] J-Link CJTAG short connect sequence

    Hi,all
    We have some problems about the J-Link cjtag connect sequence.
    wiki.segger.com/J-Link_cJTAG_specifics
    We found that the "short connect sequence" section in this link gives the connect sequence used when J-link connects to hardware that does not fully support the cjtag stanard(1149.7). We have some questions about that.
    1. Is the "short connection sequence" given in this link the connection sequence actually used by J-Link?
    2. If we only implement hardware logic (maybe only implement escape detection logic, selection sequence detect logic, Check packet, OScan1) to handle this short connect sequence, and do not implement other cjtag logic (such as control level, EPU registers, star-2 topology, commands, SSD), can J-Link successfully connect to the target?
    3. If J-link successfully connects to the target with OScan1 after completing the short connection sequence, will J-link change the scan format after this? Will it also do anything else specified in the cjtag spec other than communicating with target by transmiting OScan1 SP? Such as changing scan format, entering control level 2, initiating deselection escape.
  • Hi,

    to 1) As written in the wiki article, by default the „standard“ connect is used (because it is the spec compliant one)

    to 2) Yes

    to 3) J-Link only uses OScan1 and the commands from the connect sequence.
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