Programmer’s Model
ARM DDI 0275D
Copyright © 2002, 2003 ARM Limited. All rights reserved.
3-9
3.2.8
Trigger Counter Register, r7
This read/write register disables writes to the trace RAM after a defined number of
words have been stored, following the trigger event. The counter is used as follows:
Trace after
The counter is set to a large value (slightly less than the number of entries
in the RAM).
Trace before
The counter is set to a small value.
Trace about
The counter is set to half the number of entries in the ETB11 RAM.
The register bit allocations for the Trigger Counter Register are listed in Table 3-9.
Note
ETB_ADDR_WIDTH
is a constant used to define the width of the trace RAM address bus.
When written, the value of the Trigger Counter Register is set. You must update this
register before enabling trace capture, failure to do so can result in unexpected trace
behavior.
Reading the Trigger Counter Register samples the value of the trigger counter. During
trace capture, the value of the counter can change at any time. Therefore, if a read is
performed asynchronously the returned value might be unreliable.
You cannot write to this register if
TraceCaptEn
is HIGH.
Table 3-9 Trigger Counter Register bit allocations
Bit number
Function
[31: ETB_ADDR_WIDTH]
Reserved.
[ETB_ADDR_WIDTH-1:0]
Trigger count.
The number of datawords written into the trace RAM
following the trigger event is given by the equation:
Count = Trigger Counter Register value + 1 If this is set to
0, the trigger is ignored.
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 ...