Functional Description
ARM DDI 0275D
Copyright © 2002, 2003 ARM Limited. All rights reserved.
2-17
2.10
Clocks, and resets
This section describes:
•
•
2.10.1
Clocks
The ETB11 has three clock domains:
•
TAP controller, clocked by
DBGTCK
•
memory-mapped peripheral, clocked by
HCLK
•
remainder of the system including ETB11 registers, clocked by
CLK
.
DBGTCK is synchronous to CLK when used with ETM11RV. Synchronization issues
can therefore be ignored and are not discussed further. See
on page 1-5 for details of other ETB products,
HCLK can be synchronous or asynchronous to CLK depending on your system design.
Synchronization logic is provided for asynchronous designs. Register read and write
accesses, and RAM read and write accesses, using the AHB interface are described in:
•
•
2.10.2
Resets
There are the following resets:
•
nRESET
resets all of the ETB11 registers in the
CLK
domain.
nRESET
must
be synchronized to
CLK
using the circuit shown in Figure 2-7.
Figure 2-7 Example synchronizer
•
nDBGTRST
is the TAP controller reset signal used to reset the ETB11 TAP
controller and other
DBGTCK
domain registers.
nDBGTRST
must be
synchronized to CLK using the circuit shown in Figure 2-7.
DBGnTRST
CLK
Q
Q
Q
Q
D
D
Q
Q
DBGTCK
CLK
nDBGTRST
nRESET
ETB11
+ve
Summary of Contents for ETB11
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Page 70: ...Signal Descriptions A 6 Copyright 2002 2003 ARM Limited All rights reserved ARM DDI 0275D ...
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