Motorola DSP56012 Manual De Usuario

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Memory, Operating Modes, and Interrupts
Introduction
 
MOTOROLA
DSP56012 User’s Manual 
3-3
3.1
INTRODUCTION
The DSP56012 program and data memories are independent, and the on-chip data 
memory is divided into two separate memory spaces, X and Y. There are also two 
on-chip data ROMs in the X and Y data memory spaces, and a bootstrap ROM that 
can overlay part of the Program RAM. The data memories are divided into two 
independent spaces to work with the two Address ALUs to feed two operands 
simultaneously to the Data ALU. Through the use of Program RAM Enable bits (PEA 
and PEB) in the Operating Mode Register (OMR), four different memory 
configurations are possible to provide appropriate memory sizes for a variety of 
applications (see 
This section also includes details of the interrupt vectors and priorities and describes 
the effect of a hardware reset on the PLL Multiplication Factor (MF).
3.2
DSP56012 DATA AND PROGRAM MEMORY 
The memory in the DSP56012 can be mapped into four different configurations 
according to the PEA and PEB bits of the OMR register. The internal data and 
program memory configurations are shown in 
Note:
Internal Data and Program ROMs are factory-programmed to support 
specific applications. Refer to the 
DSP56012 Technical Data
 sheet, 
order number DSP56012/D, for more information about available 
configurations.
Table 3-1   
Internal Memory Configurations
Memory Type
No Switch
(PEA = 0, 
PEB = 0)
Switch A
(PEA = 1, 
PEB = 0)
Switch B
(PEA = 0, 
PEB = 1)
Switch A + B
(PEA = 1, 
PEB = 1)
Program RAM
0.25 K
1.0 K
1.75 K
2.5 K 
XRAM
4.0 K
3.25 K
3.25 K
2.5 K
YRAM
4.25 K
4.25 K
3.5 K
3.5 K
Program ROM
15 K
15 K
15 K
15 K 
XROM
3.5 K
3.5 K
3.5 K
3.5 K
YROM
2.0 K
2.0 K
2.0 K
2.0 K