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AT91SAM-ICE User Guide
6206B–ATARM–04-Mar-08
TCK
The electronic clock signal which times data on the TAP data lines TMS, TDI, and TDO.
TDI
The electronic signal input to a TAP controller from the data source (upstream). Usually this is seen con-
necting the Multi-ICE Interface Unit to the first TAP controller.
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 Multi-ICE Interface 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 appro5V 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.
