Decompressor Ram (Decram) Functionality; General-Purpose Memory Operation - Motorola MPC533 Reference Manual

External
Interrupt
0x500 Relocation Table
Base Address
(EIBADR)
Figure 4-3. External Interrupt Vectors Splitting
4.4

Decompressor RAM (DECRAM) Functionality

Decompressor RAM (DECRAM) is a part of the ICDU. It occupies a -Kbyte physical RAM
array block. It is mapped both in the ICDU internal address space and in the chip memory
address space. It is a single port memory and may not be accessed simultaneously from the
ICDU and U-bus.
Figure 4-4. DECRAM Interfaces Block Diagram
4.4.1

General-Purpose Memory Operation

In the case of decompression off mode, the DECRAM can serve as a two-clock access
general-purpose RAM for U-bus instruction fetches or four-clock access for read/write data
operations. The base address of the DECRAM is 0x2F 8000. See Figure 4-6. The proper
MOTOROLA
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
External Interrupt
Vector Relocator
Interrupt
000
Vector
Offset
Interrupt Code
from Interrupt
Controller
Chapter 4. Burst Buffer Controller 2 Module
Decompressor RAM (DECRAM) Functionality
Internal Memory Structure
Branch absolute to handler
Branch absolute to handler
Branch absolute to handler
Branch absolute to handler
Branch absolute to handler
Main code can start here
4-11