SMJ320VC5416 Datasheet, PDF (21/92 Pages) Texas Instruments – Fixed-Point Digital Signal Processor

Functional Overview
3.1.2 Program Memory
Software can configure their memory cells to reside inside or outside of the program address map. When the
cells are mapped into program space, the device automatically accesses them when their addresses are
within bounds. When the program-address generation (PAGEN) logic generates an address outside its
bounds, the device automatically generates an external access. The advantages of operating from on-chip
memory are as follows:
• Higher performance because no wait states are required
• Lower cost than external memory
• Lower power than external memory
The advantage of operating from off-chip memory is the ability to access a larger address space.
3.1.3 Extended Program Memory
The 5416 uses a paged extended memory scheme in program space to allow access of up to 8192K of
program memory. In order to implement this scheme, the 5416 includes several features which are also
present on C548/549/5410:
• Twenty-three address lines, instead of sixteen
• An extra memory-mapped register, the XPC
• Six extra instructions for addressing extended program space
Program memory in the 5416 is organized into 128 pages that are each 64K in length.
The value of the XPC register defines the page selection. This register is memory-mapped into data space
to address 001Eh. At a hardware reset, the XPC is initialized to 0.
3.2 On-Chip ROM With Bootloader
The 5416 features a 16K-word × 16-bit on-chip maskable ROM that can only be mapped into program memory
space.
Customers can arrange to have the ROM of the 5416 programmed with contents unique to any particular
application.
A bootloader is available in the standard 5416 on-chip ROM. This bootloader can be used to automatically
transfer user code from an external source to anywhere in the program memory at power up. If MP/MC of the
device is sampled low during a hardware reset, execution begins at location FF80h of the on-chip ROM. This
location contains a branch instruction to the start of the bootloader program.
The standard 5416 devices provide different ways to download the code to accommodate various system
requirements:
• Parallel from 8-bit or 16-bit-wide EPROM
• Parallel from I/O space, 8-bit or 16-bit mode
• Serial boot from serial ports, 8-bit or 16-bit mode
• Host-port interface boot
• Warm boot
April 2003 – Revised July 2003
SGUS035A
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