
Introduction
86
December 2003 Revised March 2005
SPRS231D
Table 25. Signal Descriptions (Continued)
SIGNAL
TYPE
DESCRIPTION
ZZG
BALL#
ZDY
BALL#
JTAG/EMULATION INTERFACE
IEEE Standard 1149.1 test clock. TCK is normally a free-running clock signal
with a 50% duty cycle. The changes on the test access port (TAP) of input
signals TDI and TMS are clocked into the TAP controller, instruction register,
or selected test data register on the rising edge of TCK. Changes at the TAP
output signal TDO occur on the falling edge of TCK.
TCK
P13
W18
I
L15
M15
RTCK
T14
Y17
ARM926EJ-S return clock emulation
I/O
N15
U19
RTDX.D[0]
M16
M14
Emulation data transmit
I/O
RTDX.D[1]
L13
P18
Emulation data transmit
I/O
RTDX.D[2]
L15
M15
Emulation data transmit
I/O
RTDX.D[3]
K13
N20
Emulation data transmit
I/O
TDI
U17
Y19
register (instruction or data) on the rising edge of TCK.
I
U15
P11
P14
W14
IEEE Standard 1149.1 test data input. TDI is clocked into the selected
TDO
IEEE Standard 1149.1 test data output. The contents of the selected register
(instruction or data) are shifted out of TDO on the falling edge of TCK. TDO
is in the high-impedance state except when the scanning of data is in
progress.
into the TAP controller on the rising edge of TCK.
O
TMS
M10
V17
I
L14
P19
IEEE Standard 1149.1 test mode select. This serial control input is clocked
TRST
R13
Y18
IEEE Standard 1149.1 test reset. TRST, when high, gives the IEEE standard
1149.1 scan system control of the operations of the device. If TRST is not
connected, or driven low, the device operates in its functional mode, and the
IEEE standard 1149.1 signals are ignored.
I
P7
Y8
WARNING:
By default, the internal pulldown on TRST is disabled. An
external pulldown is needed for proper operation of the device in functional
mode.
EMU1
N11
W17
Emulation pin 1. When TRST is driven high, EMU1 is used as an interrupt to
or from the emulator system and is defined as input/output by way of the
IEEE standard 1149.1 scan system.
I/O
P12
V15
EMU0
U16
V16
EMU0 V16 Emulation pin 0. When TRST is driven high, EMU0 is used as an
interrupt to or from the emulator system and is defined as input/output by
way of the IEEE standard 1449.1 scan system.
I/O
U7
W8
I = Input, O = Output, Z = High-Impedance