Yes, although there are some caveats. When MAJIC initializes
the JTAG scan chain, it automatically checks how many devices
are attached. If there is one, then it automatically selects
that one. If there are more than one, then the user must
specify which device on the chain corresponds to the processor
under test.
The number of devices is reported in the read-only
Ice_Jtag_Tap_Count option. You may view that with EDB's
Option Settings editor, or with the DOV command.
To specify which TAP controller (the 'state machine' part
of the JTAG interface) the MAJIC should connect to for this
debug session, you must set the Ice_Jtag_Tap_Select option.
You may set it in your startice.cmd file (after the
Ice_Power_Sense option), so you never have to think about
it again or, if you want to connect to different devices
for different debug sessions, you may set it yourself
after you start the debugger, using EDB's Option
Settings editor or the EO command.
The devices are numbered from 1 to N, where 1 is the device
whose TDO signal is connected to MAJIC, and N is the device
whose TDI signal is connected to MAJIC.
Caveats:
1. The Ice_Jtag_Tap_Select option may only be set once--it
is not presently changeable during a single debug session.
Coming real soon, though, you will be able to launch multiple
instances of the debugger to debug multiple processors simultaneously!
2. You may not use standard EJTAG-PCTrace in a multi-device
JTAG scan chain, because EJTAG redefines the JTAG signals as
PCTrace signals while tracing. Unless your CPU vendor has
implemented extensions to address this issue, then you should
put the processor on its own JTAG scan chain (perhaps through
some jumpers to make chaining optional). Otherwise, you
must not enable tracing.
