debpin-002
EPM control
registers
L4 debug interconnect
L3 interconnect
DAP
ICEPick
JTAG
Initiators
Device
Public Version
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Emulation Pin Manager
Figure 27-17. EPM Control Access
All access done by using DAP are considered debugger access; otherwise, they are considered
application access.
27.4.3.5 Claim Procedure
The application or the debugger can own the EPM control registers. The ownership is required to
configure or program the EPM. In other words, ownership determines if write access is granted to the
component. EPM ownership is exclusive. Hence, simultaneous use of EPM is not permitted. However, the
debugger can forcibly seize ownership of the EPM.
Claim state can be read in the
[31:30] CLAIMOWNERSHIP bit field.
shows the
different claim values returned by this bit field.
Table 27-103. Claim States
State
Value
Definition
Available
00
The EPM has not been claimed.
Claimed
01
The EPM has been claimed.
Enabled
10
The EPM is enabled by the owning party.
Reserved
11
Reserved
If the EPM is in a nonavailable state (the
[31:30] CLAIMOWNERSHIP bit field = 01 or 10),
the current owner can be read in the
[28] CLAIMCURRENTOWNER bit.
To change claim ownership state, write a command in the
[31:30] CLAIMOWNERSHIP bit
field.
shows the different commands to manage EPM ownership.
Table 27-104. Claim Commands
Encoding
Command
Definition
00
Release ownership
Release EPM ownership. The release command is accepted only from the owner.
01
Claim ownership
Claim access to the EPM. The claim command is successful only if the EPM is
available or requested by the debugger and the DEBUGGEROVERRIDE bit is high.
10
Enable unit
Activate the EPM for use. The enable command is accepted only from the owner.
11
No operation
The NOP command does not affect ownership or the claim state.
3643
SWPU177N – December 2009 – Revised November 2010
Debug and Emulation
Copyright © 2009–2010, Texas Instruments Incorporated