Functional Description
ARM DDI 0275D
Copyright © 2002, 2003 ARM Limited. All rights reserved.
2-13
Scan chain 0
Scan chain 0 accesses a 40-bit register with the same structure as the ETM TAP
controller shift register:
•
a 32-bit data field
•
a 7-bit address field
•
a read/write bit.
Registers are read or written under the control of bit 39, the read/write bit, and the
register access occurs when the TAP state machine passes through the Update-DR state.
The registers are described in Chapter 3
2.8.2
Instruction Register
The Instruction Register is four bits long.
There is no parity bit.
The fixed value loaded into the Instruction Register during the CAPTURE-IR controller
state is b0001. The public instructions listed in Table 2-1 are supported.
Table 2-1 Supported public instructions
Instruction
Binary
code
Description
SCAN_N
b0010
SCAN_N
connects the 5-bit scan chain selection register between
DBGTDI
and
DBGTDO
.
INTEST
b1100
INTEST
connects the scan register selected by the scan chain selection register, between
DBGTDI
and
DBGTDO
. Only scan chain 0 is implemented. Scan chain 0 is used to access
all of the ETB11 registers.
IDCODE
b1110
The
IDCODE
instruction connects the device identification register (ID register) between
DBGTDI
and
DBGTDO
. The ID register is a 32-bit register. The value of the register is set
by a
define TAP_ID_CODE
, in the
Etb11TapController.v
page 3-4 for the current ID value.
BYPASS
b1111
The
BYPASS
instruction connects a one-bit shift register, the BYPASS register, between
DBGTDI
and
DBGTDO
.
Note
The first bit shifted out is a zero.
Summary of Contents for ETB11
Page 6: ...List of Tables vi Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...
Page 8: ...List of Figures viii Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...
Page 46: ...Functional Description 2 26 Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...
Page 70: ...Signal Descriptions A 6 Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...
Page 78: ...Glossary Glossary 4 Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...