ARM9TDMI Signal Descriptions
A-6
Copyright © 1998, 1999 ARM Limited. All rights reserved.
ARM DDI0145B
A.4
JTAG and TAP controller signals
Table A-4 JTAG and TAP controller signals
Name
Direction
Description
DRIVEOUTBS
Output
Boundary Scan Cell Enable. This signal is used to control the multiplexers in the scan
cells of an external boundary scan chain. This signal changes in the UPDATE-IR state
when scan chain 3 is selected and either the INTEST, EXTEST, CLAMP or CLAMPZ
instruction is loaded. When an external boundary scan chain is not connected, this
output should be left unconnected.
ECAPCLKBS
Output
Extest Capture Clock for Boundary Scan. This is a
TCK2
wide pulse generated when
the TAP controller state machine is in the CAPTURE-DR state, the current instruction
is EXTEST and scan chain 3 is selected. This signal is used to capture the chip level
inputs during EXTEST. When an external boundary scan chain is not connected, this
output should be left unconnected.
ICAPCLKBS
Output
Intest Capture Clock. This is a
TCK2
wide pulse generated when the TAP controller
state machine is in the CAPTURE-DR state, the current instruction is INTEST and scan
chain 3 is selected. This signal is used to capture the chip level outputs during INTEST.
When an external boundary scan chain is not connected, this output should be left
unconnected.
IR[3:0]
Output
Tap Controller Instruction Register. These four bits reflect the current instruction
loaded into the TAP controller instruction register. The bits change on the falling edge
of
TCK
when the state machine is in the UPDATE-IR state.
PCLKBS
Output
Boundary Scan Update Clock. This is a
TCK2
wide pulse generated when the TAP
controller state machine is in the UPDATE-DR state and scan chain 3 is selected. This
signal is used by an external boundary scan chain as the update clock. When an external
boundary scan chain is not connected, this output should be left unconnected.
RSTCLKBS
Output
Boundary Scan Reset Clock. This signal denotes that either the TAP controller state
machine is in the RESET state, or that
nTRST
has been asserted. This may be used to
reset external boundary scan cells.
SCREG[4:0]
Output
Scan Chain Register. These four bits reflect the ID number of the scan chain currently
selected by the TAP controller. These bits change on the falling edge of
TCK
when the
TAP state machine is in the UPDATE-DR state.
SDIN
Output
Boundary Scan Serial Input Data. This signal contains the serial data to be applied to
an external scan chain, and is valid around the falling edge of
TCK
.
SDOUTBS
Input
Boundary Scan Serial Output Data. This is the serial data out of the boundary scan chain
(or other external scan chain). It should be set up to the rising edge of
TCK
. When an
external boundary scan chain is not connected, this input should be tied LOW.
Содержание ARM9TDMI
Страница 1: ...Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ARM9TDMI Technical Reference Manual ...
Страница 6: ...Contents vi Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 12: ...Preface xii Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 16: ...Introduction 1 4 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 22: ...Programmer s Model 2 6 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 36: ...ARM9TDMI Processor Core Memory Interface 3 14 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 54: ...ARM9TDMI Coprocessor Interface 4 18 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 110: ...Test Issues 6 6 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 138: ...ARM9TDMI AC Characteristics 8 20 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 150: ...ARM9TDMI Signal Descriptions A 12 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...
Страница 154: ...Index Index 4 Copyright 1998 1999 ARM Limited All rights reserved ARM DDI0145B ...