Data Sheet
June 2001
DSP16410B Digital Signal Processor
38
Agere Systems—Proprietary
Use pursuant to Company instructions
Agere Systems Inc.
4 Hardware Architecture
(continued)
4.5 Memory Maps
(continued)
4.5.1 Private Internal Memory
Each core has its own private internal memories for
program and data storage. CORE0 has IROM0,
CACHE0, and TPRAM0. CORE1 has IROM1,
CACHE1, and TPRAM1. A core cannot directly access
the other core’s private memory. However, the DMAU
can access both TPRAM0 and TPRAM1 and can move
data between these two memories to facilitate core-to-
core communication (see
Section 4.8 on page 45
).
TPRAM is described in more detail in
Section 4.6 on
page 43
. Cache memory is described in detail in the
DSP16000 Digital Signal Processor Core Information
Manual. IROM contains boot and HDS code and is
described in
Section 5 on page 205
.
4.5.2 Shared Internal I/O
The 128 Kword internal I/O memory component is
accessible by both cores in their Y-memory spaces and
by the DMAU in its Z-memory space. Any access to
this memory component is made over the system bus
and is arbitrated by the SEMI. The internal shared I/O
memory component consists of:
2 Kwords of shared local memory (SLM). SLM can
be used for core-to-core communication (see
Section 4.8 on page 45
). SLM is described in
Section 4.1.4 on page 17
.
Memory-mapped control and data registers within
the following peripherals:
— DMAU
— SEMI
— PIU
— SIU0
— SIU1
Only a small portion of the 128 Kwords reserved for
internal I/O is actually populated with memory or regis-
ters. Any access to the internal I/O memory compo-
nent takes multiple cycles to complete. DSP core or
DMAU writes take a minimum of two CLK cycles to
complete. DSP core or DMAU reads take a minimum
of five CLK cycles to complete.
4.5.3 Shared External I/O and Memory
External I/O and memory consists of three shared
components: EIO, ERAM, and EROM. EIO and ERAM
are accessible in the Y-memory spaces of both cores
and also in the DMAU’s Z-memory space. EROM is
normally read-only and accessible only in the X-mem-
ory spaces of both cores. If the programmer sets the
WEROM field in the memory-mapped
ECON1
register
(see
Table 60 on page 110
), EROM takes the place of
ERAM in the Y-memory spaces of both cores and in
the DMAU’s Z-memory space (see
Section 4.5.5 on
page 40
and
Section 4.5.6 on page 41
for details).
This allows the EROM component to be written for pro-
gram downloads to external X memory.
The physical size of the EIO, ERAM, and EROM com-
ponents can be expanded from the sizes defined in
Table 11 on page 37
by employing the ESEG[3:0]
pins. The external memory system can use ESEG[3:0]
in either of the following ways:
1. ESEG[3:0] can be interpreted by the external mem-
ory system as four separate decoded address
enable signals. Each ESEG[3:0] pin individually
selects one of four segments for each memory
component. This results in four glueless 512 Kword
(1 Mbyte) ERAM segments, four glueless 512 Kword
(1 Mbyte) EROM segments, and four glueless
128 Kword (256 KB) EIO segments.
2. ESEG[3:0] can be interpreted by the external mem-
ory system as an extension of the address bus, i.e.,
the ESEG[3:0] pins can be concatenated with the
EAB[18:0] pins to form a 23-bit address. This results
in one glueless 8 Mword (16 Mbytes) ERAM seg-
ment, one glueless 8 Mword (16 Mbytes) EROM
segment, and one glueless 2 Mword (4 Mbytes) EIO
segment.
See
Section 4.14.1.4 on page 105
for details on config-
uring the ESEG[3:0] pins.