Segger J-Link User Manual page 201

199
TDO
The electronic signal output from a TAP controller to the data sink (downstream).
Usually, this is seen connecting the last TAP controller to the J-Link / J-Trace Inter-
face Unit.
Test Access Port (TAP)
The port used to access a device's TAP Controller. Comprises TCK, TMS, TDI, TDO,
and nTRST (optional).
Transistor-transistor logic (TTL)
A type of logic design in which two bipolar transistors drive the logic output to one or
zero. LSI and VLSI logic often used TTL with HIGH logic level approaching +5V and
LOW approaching 0V.
Watchpoint
A location within the image that will be monitored and that will cause execution to
stop when it changes.
Word
A 32-bit unit of information. Contents are taken as being an unsigned integer unless
otherwise stated.
J-Link / J-Trace (UM08001) © 2004-2009 SEGGER Microcontroller GmbH & Co. KG