Features
shows the functionality supported by the members of the MPC875/MPC870.
Table 1. MPC875/870 Devices
Cache
Part
I Cache
MPC875
MPC870
8 Kbyte
8 Kbyte
D Cache
8 Kbyte
8 Kbyte
10BaseT
1
—
10/100
2
2
1
—
1
1
1
1
Ethernet
SCC
SMC
USB
Security
Engine
Yes
No
2
Features
The MPC875/870 is comprised of three modules that each use the 32-bit internal bus: a MPC8xx core, a system
integration unit (SIU), and a communications processor module (CPM).
The following list summarizes the key MPC875/870 features:
•
•
Embedded MPC8xx core up to 133 MHz
Maximum frequency operation of the external bus is 80 MHz (in 1:1 mode)
— The 133-MHz core frequency supports 2:1 mode only.
— The 66-/80-MHz core frequencies support both the 1:1 and 2:1 modes.
Single-issue, 32-bit core (compatible with the PowerPC architecture definition) with thirty-two 32-bit
general-purpose registers (GPRs)
— The core performs branch prediction with conditional prefetch and without conditional execution.
— 8-Kbyte data cache and 8-Kbyte instruction cache (see
– Instruction cache is two-way, set-associative with 256 sets in 2 blocks
– Data cache is two-way, set-associative with 256 sets
– Cache coherency for both instruction and data caches is maintained on 128-bit (4-word) cache
blocks.
– Caches are physically addressed, implement a least recently used (LRU) replacement algorithm, and
are lockable on a cache block basis.
— MMUs with 32-entry TLB, fully associative instruction and data TLBs
— MMUs support multiple page sizes of 4, 16, and 512 Kbytes, and 8 Mbytes; 16 virtual address spaces
and 16 protection groups
— Advanced on-chip emulation debug mode
Up to 32-bit data bus (dynamic bus sizing for 8, 16, and 32 bits)
32 address lines
Memory controller (eight banks)
— Contains complete dynamic RAM (DRAM) controller
— Each bank can be a chip select or RAS to support a DRAM bank.
— Up to 30 wait states programmable per memory bank
— Glueless interface to DRAM, SIMMS, SRAM, EPROMs, Flash EPROMs, and other memory devices
— DRAM controller programmable to support most size and speed memory interfaces
— Four CAS lines, four WE lines, and one OE line
•
•
•
•
MPC875/MPC870 Hardware Specifications, Rev. 3.0
2
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Freescale Semiconductor
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
