The DSTREAM unit has two reset signals connected to the debug target hardware:
nTRST drives the JTAG nTRST signal on the ARM processor. It is an output that is activated whenever the debug software has to re-initialize the debug interface in the target system.
nSRST is a bidirectional signal that both drives and senses the system reset signal on the target. By default, this output is driven LOW by the debugger to re-initialize the target system.
The target hardware must pull the reset lines to their inactive state to assure normal operation when the JTAG interface is disconnected. In the DSTREAM unit, the strong pull-up/pull-down resistance is approximately 33Ω, and the weak pull-up/pull-down resistance is approximately 4.7kΩ. Because you can select the drive strength for nTRST and nSRST, target assemblies with a variey of different reset configurations can be supported.