MC68030RC50C Freescale Semiconductor, MC68030RC50C Datasheet - Page 323

• 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
9-22
TABLE ADDRESS
M
PAGE ADDRESS
S
L/U
LIMIT
the index into the table at the next lower level of the translation tree. If the
the M bit is zero, except after a descriptor with the WP bit set is encountered,
This 24-bit field contains the physical base address of a page in memory.
The low-order bits of the address are supplied b y t h e logical address. When
the page size is larger than 256 bytes, one or more of the least significant
This bit specifies the type of limit in the LIMIT field. When the L/U bit is
the next level of the tree must be greater than or equal to the value in the
and the index value must be less than or equal to the LIMIT. An out-of-
and causes the table search to abort.
This 15-bit field contains a limit to which the index portion of an address
descriptor is an early termination page descriptor, the limit field is still used
as a check on the next index field of the logical address.
This bit identifies a modified page. The MC68030 sets the M bit in the
corresponding page descriptor before a write operation to a page for which
or after a supervisor violation is encountered. An access is considered to
The MC68030 never clears this bit.
This bit identifies a pointer table or a page as a supervisor only table or
other level of the translation tree.
This 28-bit field contains the physical base address of a table of descriptors.
The low-order bits of the address are supplied by the logical address.
set, the LIMIT field contains the unsigned lower limit; the index value for
bounds access causes the B bit in the ATC entry for the address to be set
is compared to detect an out-of-bounds index. The limit check applies to
be a write for updating purposes if either the R/W or RMC signal is low.
bits of this field are not used. The number of unused bits is equal to the
PS field value in the TC register minus eight.
page. When the S bit is set, only programs operating at the supervisor
privilege level are allowed to access the portion of the logical address
mapped by this descriptor. If this bit is clear, accesses using this descriptor
are not restricted to supervisor-only unless the access is restricted by some
LIMIT field. When the bit is cleared, the limit is an unsigned upper limit,
MC68030 USER'S MANUAL
MOTOROLA