Reserved Memory Spaces - Motorola DSP56009 User Manual

Memory, Operating Modes, and Interrupts
DSP56009 Data And Program Memory Maps
The bytes will be packed into 512 24-bit words and stored in contiguous Program
RAM memory locations starting at P:$0000.
Note: The routine loads data starting with the least significant byte of P:$0000.
Programs can be loaded from the SHI in the SPI mode if MC:MB:MA = 101, or in the
2
I C mode if MC:MB:MA = 111. The internal Program RAM is loaded with up to 512
words that are 24-bits long and are received through the SHI. The SHI operates in the
Slave mode, with the 10-word FIFO enabled, and with the HREQ pin enabled for
receive operation. The OnCE port is enabled by the bootstrap code.
The contents of the bootstrap ROM are provided in Appendix A.
3.2.5

Reserved Memory Spaces

The reserved memory spaces should not be accessed by the user. They are reserved
for future expansion. Write operations to the reserved range are ignored. Read
operations from addresses in the reserved range return the value $000005. If an
instruction fetch is attempted from an address in the reserved area, the value
returned is $000005, which is the opcode for the ILLEGAL instruction.
3.3 DSP56009 DATA AND PROGRAM MEMORY MAPS
The memory in the DSP56009 can be mapped into four different configurations
according to the PEA and PEB bits in the OMR. Memory maps for each of the four
configurations are shown in Figure 3-1, Figure 3-2, Figure 3-3, and Figure 3-4 on
the following pages.
MOTOROLA DSP56009 User's Manual 3-5