GR740-UM-DS, Nov 2017, Version 1.7
398
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GR740
33.6.7 AHB Trace buffer control register
The AHB trace buffer is controlled by the AHB trace buffer control register:
33.6.8 AHB trace buffer index register
The AHB trace buffer index register contains the address of the next trace line to be written.
Table 530.
0x000040 - ATBC - AHB trace buffer control register
31
24 23
16 15
9
8
7
6
5
4
3
2
1
0
RESERVED
DCNT
RESERVED
DF SF TE TF
BW
BR DM EN
0
0
0
0
0
0
0
0x10
0
0
*
r
rw
r
rw rw rw rw
r
rw rw rw
31: 24
RESERVED
23: 16
Trace buffer delay counter (DCNT) - Specifies the number of lines that should be written in the trace
buffer befiore entering debug mode after a AHB break/watchpoint has been hit.
15: 9
RESERVED
8
Enable Debug Mode Timer Freeze (DF) - The time tag counter keeps counting in debug mode when
at least one of the processors has the internal timer enabled. If this bit is set to ‘1’ then the time tag
counter is frozen when the processors have entered debug mode.
7
Sample Force (SF) - If this bit is written to ‘1’ it will have the same effect on the AHB trace buffer as
if HREADY was asserted on the bus at the same time as a sequential or non-sequential transfer is
made. This means that setting this bit to ‘1’ will cause the values in the trace buffer’s sample regis-
ters to be written into the trace buffer, and new values will be sampled into the registers. This bit will
automatically be cleared after one clock cycle.
Writing to the trace buffer still requires that the trace buffer is enabled (EN bit set to ‘1’) and that the
CPU is not in debug mode or that tracing is forced (TF bit set to ‘1’). This functionality is primarily
of interest if the Processor AHB bus appears to have frozen.
6
Timer enable (TE) - Activates time tag counter also in debug mode. Note that this activates the same
timer source as used for the processor up-counters described in section 6.10.4.
5
Trace force (TF) - Activates trace buffer also in debug mode.
4: 3
Bus width (BW) - This value corresponds to log2(Supported bus width / 32). Value is 2.
2
Break (BR) - If set, the processor will be put in debug mode when AHB trace buffer stops due to
AHB breakpoint hit.
1
Delay counter mode (DM) - Indicates that the trace buffer is in delay counter mode.
0
Trace enable (EN) - Enables the trace buffer.
The reset value of this field is 1 when the external signal BREAK is low, otherwise 0.
Table 531.
0x000044 - ATBI - AHB trace buffer index register
31
12 11
4
3
0
RESERVED
INDEX
RESERVED
0
NR
0
r
rw
r
31: 12
RESERVED
11: 4
Trace buffer index counter (INDEX) - Address of next trace line to be written.
3: 0
RESERVED