MC68030RC50C Freescale Semiconductor, MC68030RC50C Datasheet - Page 321

• Manufacturer Part Number: MC68030RC50C
• Description: IC MPU 32BIT ENHANCED 128-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68030RC50C

• Processor Type: M680x0 32-Bit
• Speed: 50MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 128-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

9
9.5 T R A N S L A T I O N TABLE DETAILS
9.5.1 Descriptor Details
9.5.1.1 DESCRIPTOR FIELD DEFINITIONS.
9-20
The details of translation tables and their use include detailed descriptions
the protection techniques available with the MC68030 MMU.
The descriptor details include detailed descriptions of the short- and long-
format descriptors used in the translation trees. The fields that apply to all
than one type of descriptor. This section lists these fields and describes the
of the descriptors, table searching, translation table structure variations, and
descriptors are described in the first paragraph.
use of each field.
DT
PHYSICAL ADDRESS
troller without translation.
This 2-bit field contains the descriptor type; the first two types apply to
the descriptor itself. The other two types apply to the descriptors in the
table at the next level of the tree. The values are defined as follows:
This 24-bit field contains the physical address bits (A31-A8) from the page
descriptor corresponding to the logical address. When the page size is
larger than 256 bytes, not all bits in the physical address field are used.
All page index bits of the logical address are transferred to the bus con-
$0
$1
This code identifies the current descriptor as an invalid descriptor.
A table search ends when an invalid descriptor is encountered.
This code identifies the current descriptor as a page descriptor.
The page descriptor is a normal page descriptor when it resides
A table search ends when a page descriptor of either type is en-
INVALID
PAGE DESCRIPTOR
in a page table (in the bottom level of the translation tree). A page
descriptor at a higher level is an early termination page descriptor.
countered.
MC68030 USER'S MANUAL
All descriptor fields are used in more
MOTOROLA