Epson ARM.POWERED ARM720T - Manual (Page 216)

Glossary
Glossary-6 EPSON ARM720T CORE CPU MANUAL
Test Access Port
The collection of four mandatory and one optional terminals that form the
input/output and control interface to a JTAG boundary-scan architecture.
The mandatory terminals are TDI, TDO, TMS, and TCK. The optional
terminal is nTRST.
Thumb instruction
A halfword which specifies an operation for an ARM processor in Thumb
state to perform. Thumb instructions must be halfword-aligned.
Thumb state
A processor that is executing Thumb (16-bit) instructions is operating in
Thumb state.
UND
See Undefined.
Undefined
Indicates an instruction that generates an undefined instruction trap.
UNP
See Unpredictable
Unpredictable
Means the result of an instruction cannot be relied upon. Unpredictable
instructions must not halt or hang the processor, or any parts of the
system.
Unpredictable fields
Do not contain valid data, and a value can vary from moment to moment,
instruction to instruction, and implementation to implementation.
Watchpoint
A location in the image that is monitored. If the value stored there changes,
the debugger halts execution of the image.
See also Breakpoint.