ARM R4 Manuale Utente
Debug
ARM DDI 0363E
Copyright © 2009 ARM Limited. All rights reserved.
11-14
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11.4.5
CP14 c1, Debug Status and Control Register
The DSCR contains status and control information about the debug unit. Figure 11-5 shows the
bit arrangement of the DSCR.
bit arrangement of the DSCR.
Figure 11-5 Debug Status and Control Register format
Table 11-10 shows how the bit values correspond with Debug Status and Control Register
functions.
functions.
31 30 29 28
16 15 14 13 12 11 10
6 5
2 1 0
MOE
9
7
8
Core halted
Core restarted
26 25 24 23
PipeAdv
InstrCompl
22 21 20 19 18
Monitor mode
Halting mode
ARM
DbgAck
IntDis
Comms
Sticky imprecise abort
Sticky Undefined
Reserved
Sticky precise abort
DTR access
Discard
imprecise
abort
imprecise
abort
27
Reserved
DTRTXfull
DTRRXfull
Reserved
Reserved
Reserved
Table 11-10 Debug Status and Control Register functions
Bits
Field
Function
[31]
Reserved
RAZ on reads, SBZP on writes.
[30]
DTRRXfull
The DTRRXfull flag:
0 = Read-DTR, DTRRX, empty, reset value
1 = Read-DTR, DTRRX, full.
When set, this flag indicates to the processor that there is data available to read at the
DTRRX. It is automatically set on writes to the DTRRX by the debugger, and is cleared
when the processor reads the CP14 DTR. If the flag is not set, the DTRRX returns an
Unpredictable value.
0 = Read-DTR, DTRRX, empty, reset value
1 = Read-DTR, DTRRX, full.
When set, this flag indicates to the processor that there is data available to read at the
DTRRX. It is automatically set on writes to the DTRRX by the debugger, and is cleared
when the processor reads the CP14 DTR. If the flag is not set, the DTRRX returns an
Unpredictable value.
[29]
DTRTXfull
The DTRTXfull flag:
0 = Write-DTR, DTRTX, empty, reset value
1 = Write-DTR, DTRTX, full.
When clear, this flag indicates to the processor that the DTRTX is ready to receive data. It
is automatically cleared on reads of the DTRTX by the debugger, and is set when the
processor writes to the CP14 DTR. If this bit is set and the processor attempts to write to
the DTRTX, the register contents are overwritten and the DTRRXfull flag remains set.
0 = Write-DTR, DTRTX, empty, reset value
1 = Write-DTR, DTRTX, full.
When clear, this flag indicates to the processor that the DTRTX is ready to receive data. It
is automatically cleared on reads of the DTRTX by the debugger, and is set when the
processor writes to the CP14 DTR. If this bit is set and the processor attempts to write to
the DTRTX, the register contents are overwritten and the DTRRXfull flag remains set.
[28:26]
Reserved
RAZ on reads, SBZP on writes.
[25]
PipeAdv
Sticky pipeline advance read-only bit. This bit enables the debugger to detect whether the
processor is idle. In some situations, this might mean that the system bus port is
deadlocked. This bit is set to 1 when the processor pipeline retires one instruction. It is
cleared by a write to DRCR[3].
0 = no instruction has completed execution since the last time this bit was cleared
1 = an instruction has completed execution since the last time this bit was cleared.
processor is idle. In some situations, this might mean that the system bus port is
deadlocked. This bit is set to 1 when the processor pipeline retires one instruction. It is
cleared by a write to DRCR[3].
0 = no instruction has completed execution since the last time this bit was cleared
1 = an instruction has completed execution since the last time this bit was cleared.