You can use JTAG debugging equipment and the JTAG connector, or the USB debug port, to:
connect a debugger to the ARM926EJ-S core and download programs to memory and debug them
program new configuration images into the configuration flash, FPGA, and PLDs on the board. (You cannot program the normal flash from configuration mode.)
The setup for using a JTAG interface with the PB926EJ-S is shown in Figure 2.2.
The setup for using the USB debug port on the PB926EJ-S is shown in Figure 2.3. The PB926EJ-S contains logic that interfaces the USB debug port to the onboard JTAG signals.