DSP56303 FREESCALE [Freescale Semiconductor, Inc], DSP56303 Datasheet - Page 19

• Manufacturer Part Number: DSP56303
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

1.6.5 JTAG TAP and OnCE Module
In the DSP56300 core is a dedicated user-accessible TAP that is fully compatible with the IEEE
1149.1 Standard Test Access Port and Boundary Scan Architecture. Problems with testing
high-density circuit boards led to the development of this standard under the sponsorship of the
Test Technology Committee of IEEE and the JTAG. The DSP56300 core implementation
supports circuit-board test strategies based on this standard. The test logic includes a TAP with
four dedicated signals, a 16-state controller, and three test data registers. A boundary scan
register links all device signals into a single shift register. The test logic, implemented utilizing
static logic design, is independent of the device system logic. For details on the JTAG port,
consult the DSP56300 Family Manual.
The OnCE module interacts with the DSP56300 core and its peripherals nonintrusively so that
you can examine registers, memory, or internal peripherals. This facilitates hardware and
software development on the DSP56300 core processor. OnCE module functions are provided
through the JTAG TAP signals. For details on the OnCE module, consult the DSP56300 Family
Manual.
1.6.6 Internal Memory
The memory space of the DSP56300 core is partitioned into program, X data, and Y data
memory space. The data memory space is divided into X and Y data memory in order to work
with the two address ALUs and to feed two operands simultaneously to the data ALU. Memory
space includes internal RAM and ROM and can be expanded off-chip under software control. For
details on internal memory, see Chapter 3, Memory Configuration. Program RAM, instruction
cache, X data RAM, and Y data RAM size are programmable, as shown in Table 1-2.
There is an internal 192 × 24-bit bootstrap ROM.
1.6.7 External Memory Expansion
Memory can be expanded externlly as follows:
Freescale Semiconductor
Instruction
Data memory expansion to two 256 K × 24-bit word memory spaces using the standard
external address lines
disabled
disabled
enabled
enabled
Cache
disabled
disabled
enabled
enabled
Switch
Mode
Program RAM
4096 × 24-bit
3072 × 24-bit
2048 × 24-bit
1024 × 24-bit
Table 1-3. Internal Memory
DSP56303 User’s Manual, Rev. 2
Size
1024 × 24-bit
1024 × 24-bit
Cache Size
Instruction
0
0
X Data RAM Size
2048 × 24-bit
2048 × 24-bit
3072 × 24-bit
3072 × 24-bit
DSP56300 Core Functional Blocks
Y Data RAM Size
2048 × 24-bit
2048 × 24-bit
3072 × 24-bit
3072 × 24-bit
1-9