Chain padding in XJTAG

XJLink2

Data is sent to the JTAG chain by the XJLink2 (or XJLink2-based JTAG controller) in a straightforward manner with no padding bits. The only data added to the chain by XJTAG is the 'magic' byte (see below) at the beginning of a JTAG scan, but this is always disabled when using XJAPI.

Magic Byte

• XJTAG adds a known byte (the 'magic' byte) to the beginning of the chain and checks that it exits the chain intact so that it can verify that the chain is connected correctly. Note that this is always disabled for the XJAPI.