Article Details

ID: 234
Case Type: faq
Category: Device Programming
Related To: ispDaisy Chain Download
Family: All Devices

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Which device is the number 1 device in the JTAG chain?

Three identical Lattice devices are in the JTAG chain but each needs different JEDEC pattern. The ispVM GUI shows index number 1, 2, and 3. It is hard for users to match the index number shown in the ispVM to the physical location of the device in the chain


The device that is connected to the TDI is the first device in the chain (index number 1). And the device that is driving TDO is the last in the chain with the highest index number (index number 3 in this case). Anything in between is sequentially numbered.