Specifications

NEWS 2012
www.lauterbach.com8
Fast Host Interface
The amount of trace data that is exported via the trace
port depends on the target system hardware. The
number of cores, the number of trace port pins, and
the trace clock speed are all important parameters.
The protocol used by the core trace logic plays also an
important role. For example, the ARM PTM protocol
is more compact than the ARM ETMv3 protocol (see
gure9).
The embedded software is another major variable. A
software program that performs many jumps and
retrieves data/instructions mainly from the cache pro-
duces more trace data per second than a software
program that processes many sequential instructions
and must frequently wait for the availability of data/
instructions.
The amount of data varies but it is always large. Stream-
ing only works properly, if the transfer rate between the
tool and the host computer is fast enough to transfer
all of the data from the trace port to the host computer
without any data loss. The 1 GBit Ethernet interface is
the only recommended interface for the PowerTrace II.
The programming of the trace logic on the chip can
be used to directly influence the amount of trace data
being generated. The logic should be programmed so
that only trace information which is relevant to the code-
coverage analysis is being generated. To illustrate this
point, the following two examples are provided.
ETM/PTM: Optimal Configuration
ETM and PTM are different implementations of the
core trace logic on the ARM/Cortex architectures.
The ETM can be configured so that trace information
is produced only for the instructions executed by the
program. Information about the read/write operations
is not needed for code-coverage. By default the PTM
only generates information about the program flow.
Therefore the PTM does not need to be configured.
Both trace sources encode the virtual address instruc-
tions. If an embedded design uses an operating sys-
tem, such as Linux or Embedded Windows, virtual ad-
dresses cannot be mapped unambiguously to physical
TRACE32 trace tools are available in two designs,
which differ especially in relation to their features.
• 256or512MBytetracememory
• USB2.xand100MBitEthernet
• 80MBit/sasmaximumtransferratetohost 
computer
• Softwarecompressionoftracedata(factor3)
• Memoryinterfacewith100MHz
• 1/2/4GBytetracememory
• USB2.xand1GBitEthernet
• 500MBit/sasmaximumtransferrateto 
host computer
• HardwarecompressionoftracedataforETMv3 
and PTM (factor 6)
• Memoryinterfacewith233MHz
PowerTrace vs. PowerTrace II
PowerTrace
PowerTrace II
Average load
Maximum load
20 4 6 8 10 GBit/s
3.2 GBit/s max. transmission rate
Cortex-R4
@ 500MHz
ETMv3
Cortex-A9
@ 1GHz
PTM
4 x Cortex-A9
@ 1GHz
PTM
Fig.9: Atransmissionrateof3.2GB/sisgenerallyadequateforstreamingprogramsequenceinformationonthehost.