Specifications

Table Of Contents
ARM Debugger 81 ARM specific SYStem Commands
©1989-2014 Lauterbach GmbH
SYStem.LOCK Tristate the JTAG port
Default: OFF.
If the system is locked no access to the JTAG port will be performed by the debugger. While locked the JTAG
connector of the debugger is tristated. The intention of the lock command is for example to give JTAG
access to another tool. The process can also be automated, see SYStem.CONFIG TriState.
It must be ensured that the state of the ARM core JTAG state machine remains unchanged while the system
is locked. To ensure correct hand over the options SYStem.CONFIG TAPState and SYStem.CONFIG
TCKLevel must be set properly. They define the TAP state and TCK level which is selected when the
debugger switches to tristate mode. Please note: nTRST must have a pull-up resistor on the target,
EDBGRQ must have a pull-down resistor.
Format: SYStem.LOCK [ON | OFF]