OMAP-L137 Datasheet, PDF (11/219 Pages) Texas Instruments – Low-Power Applications Processor

www.ti.com
OMAP-L137 Low-Power Applications Processor
SPRS563A – SEPTEMBER 2008 – REVISED OCTOBER 2008
The write buffer is used for all writes to a noncachable bufferable region, write-through region and write
misses to a write-back region. A separate buffer is incorporated in the Dcache for holding write-back for
cache line evictions or cleaning of dirty cache lines. The main write buffer has 16-word data buffer and a
four-address buffer. The Dcache write-back has eight data word entries and a single address entry.
3.3.5 Advanced High-Performance Bus (AHB)
The ARM Subsystem uses the AHB port of the ARM926EJ-S to connect the ARM to the Config bus and
the external memories. Arbiters are employed to arbitrate access to the separate D-AHB and I-AHB by the
Config Bus and the external memories bus.
3.3.6 Embedded Trace Macrocell (ETM) and Embedded Trace Buffer (ETB)
To support real-time trace, the ARM926EJ-S processor provides an interface to enable connection of an
Embedded Trace Macrocell (ETM). The ARM926ES-J Subsystem in the OMAP-L137 also includes the
Embedded Trace Buffer (ETB). The ETM consists of two parts:
• Trace Port provides real-time trace capability for the ARM9.
• Triggering facilities provide trigger resources, which include address and data comparators, counter,
and sequencers.
The OMAP-L137 trace port is not pinned out and is instead only connected to the Embedded Trace Buffer.
The ETB has a 4KB buffer memory. ETB enabled debug tools are required to read/interpret the captured
trace data.
3.3.7 ARM Memory Mapping
By default the ARM has access to most on and off chip memory areas, including the DSP Internal
memories, EMIFA, EMIFB, and the additional 128K byte on chip shared SRAM. Likewise almost all of the
on chip peripherals are accessible to the ARM by default.
To improve security and/or robustness the OMAP-L137 has extensive memory and peripheral protection
units which can be configured to limit access rights to the various on / off chip resources to specific hosts;
including the ARM as well as other master peripherals. This allows the system tasks to be partitioned
between the ARM and DSP as best suites the particular application; while enhancing the overall
robustness of the solution.
See Table 3-3 for a detailed top level OMAP-L137 memory map that includes the ARM memory space.
Submit Documentation Feedback
Device Overview
11