Programmer’s Model
ARM DDI 0275D
Copyright © 2002, 2003 ARM Limited. All rights reserved.
3-11
3.3
Software access to the ETB11 using the AHB interface
The AHB interface:
•
is a slave-based interface
•
resides at a user-defined block of system memory, for example
0x13800000
•
enables software access to the ETB11 registers and RAM
•
has read and write access to the ETB11 registers.
ETB memory is aliased into the interface memory space, so that software can read out
the trace information stored in the memory and additionally write to the ETB11
memory.
Registers contained in the ETB11 that require software access are listed in Table 3-11.
The base addresses of the ETB11 registers and the RAM are defined by the AHB
decoder.
Software access to registers is only enabled when bit 2 of the control register
(SoftwareCntl) is set to 1. This is the default and is set to 1 on reset.
Additionally, software access to ETB11 RAM is only enabled when bit 0 of the control
register is set to 0 (ETB11 is enabled).
The interface contains an input signal called
SWEN
. When this signal is LOW, the
interface is disabled. The AHB interface is enabled if
SWEN
is HIGH.
Table 3-11 Registers that require software access
Register
number
Description
Location
000 0000
Identification Register
Register base address (for example,
0x13800000
)
000 0001
RAM Depth Register
Register base a
0x4
(for example,
0x13800004
)
000 0010
RAM Width Register
Register base a
0x8
(for example,
0x13800008
)
000 0011
Status Register
Register base a
0xC
(for example,
0x1380000C
)
000 0110
RAM Write Pointer Register
Register base a
0x18
(for example,
0x13800018
)
000 0111
Trigger Counter Register
Register base a
0x1C
(for example,
0x1380001C
)
000 1000
Control Register
Register base a
0x20
(for example,
0x13800020
)
-
Aliased trace RAM
RAM base address (for example,
0x13900000
)
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 ...