11–46 Altera Corporation
Stratix Device Handbook, Volume 2 July 2005
Configuration Schemes
send JTAG data to the device involve moving the TAP controller through
either the data register leg or the instruction register leg of the state
machine. For example, loading a JTAG instruction involves moving the
TAP controller to the SHIFT_IR state and shifting the instruction into the
instruction register through the TDI pin. Next, the TAP controller is
moved to the RUN_TEST/IDLE state where a delay is implemented to
allow the instruction time to be latched. This process is identical for data
register scans, except that the data register leg of the state machine is
traversed.
The high-level Jam instructions are the DRSCAN instruction for scanning
the JTAG data register, the IRSCAN instruction for scanning the
instruction register, and the WAIT command that causes the state machine
to sit idle for a specified period of time. Each leg of the TAP controller is
scanned repeatedly, according to instructions in the JBC file, until all of
the target devices are programmed.
Figure 11–25 illustrates the functional behavior of the Jam Player when it
parses the JBC file. When the Jam Player encounters a DRSCAN, IRSCAN,
or WAIT instruction, it generates the proper data on TCK, TMS, and TDI to
complete the instruction. The flow diagram shows branches for the
DRSCAN, IRSCAN, and WAIT instructions. Although the Jam Player
supports other instructions, they are omitted from the flow diagram for
simplicity.
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