Dual-issue integer core
— A core version of the EC603e microprocessor
— Separate 16-Kbyte data and instruction caches:
– Four-way set associative
– Physically addressed
– LRU replacement algorithm
— PowerPC architecture-compliant memory management unit (MMU)
— Common on-chip processor (COP) test interface
— High-performance (4.4–5.1 SPEC95 benchmark at 200 MHz; 280 Dhrystones MIPS at
200 MHz)
— Supports bus snooping for data cache coherency
— Floating-point unit (FPU)
• Separate power supply for internal logic and for I/O
• Separate PLLs for G2 core and for the CPM
— G2 core and CPM can run at different frequencies for power/performance optimization
— Internal core/bus clock multiplier that provides 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1, 6:1 ratios
— Internal CPM/bus clock multiplier that provides 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1, 6:1 ratios
• 64-bit data and 32-bit address 60x bus
— Bus supports multiple master designs
— Supports single- and four-beat burst transfers
— 64-, 32-, 16-, and 8-bit port sizes controlled by on-chip memory controller
— Supports data parity or ECC and address parity
• 32-bit data and 18-bit address local bus
— Single-master bus, supports external slaves
— Eight-beat burst transfers
— 32-, 16-, and 8-bit port sizes controlled by on-chip memory controller
• System interface unit (SIU)
— Clock synthesizer
— Reset controller
— Real-time clock (RTC) register
— Periodic interrupt timer
— Hardware bus monitor and software watchdog timer
— IEEE Std 1149.1™ JTAG test access port
• Twelve-bank memory controller
— Glueless interface to SRAM, page mode SDRAM, DRAM, EPROM, Flash and other  userdefinable peripherals
— Byte write enables and selectable parity generation
— 32-bit address decodes with programmable bank size
— Three user programmable machines, general-purpose chip-select machine, and page-mode pipeline SDRAM machine
— Byte selects for 64 bus width (60x) and byte selects for 32 bus width (local)
— Dedicated interface logic for SDRAM
• CPU core can be disabled and the device can be used in slave mode to an external core
• Communications processor module (CPM)
— Embedded 32-bit communications processor (CP) uses a RISC architecture for flexible support for communications protocols
— Interfaces to G2 core through on-chip 24-Kbyte dual-port RAM and DMA controller
— Serial DMA channels for receive and transmit on all serial channels
— Parallel I/O registers with open-drain and interrupt capability
— Virtual DMA functionality executing memory-to-memory and memory-to-I/O transfers
— Three fast communications controllers (two on the MPC8255) supporting the following
protocols:
– 10/100-Mbit Ethernet/IEEE Std 802.3™ CDMA/CS interface through media independent
interface (MII)
– ATM—Full-duplex SAR protocols at 155 Mbps, through UTOPIA interface, AAL5, AAL1,
AAL0 protocols, TM 4.0 CBR, VBR, UBR, ABR traffic types, up to 16 K external connections
– HDLC—Up to T3 rates (clear channel)
— Two multichannel controllers (MCCs) (only MCC2 on the MPC8255)
– Each MCC handles 128 serial, full-duplex, 64-Kbps data channels. Each MCC can be split into four subgroups of 32 channels each.
– Almost any combination of subgroups can be multiplexed to single or multiple TDM interfaces up to four TDM interfaces per MCC
— Four serial communications controllers (SCCs) identical to those on the MPC860, supporting
the digital portions of the following protocols:
– Ethernet/IEEE 802.3 CDMA/CS
– HDLC/SDLC and HDLC bus
– Universal asynchronous receiver transmitter (UART)
– Synchronous UART
– Binary synchronous (BISYNC) communications
— Two serial management controllers (SMCs), identical to those of the MPC860
– Provide management for BRI devices as general circuit interface (GCI) controllers in  timedivision-multiplexed (TDM) channels
– UART (low-speed operation)
— One serial peripheral interface identical to the MPC860 SPI
— One inter-integrated circuit (I2C) controller (identical to the MPC860 I2C controller)
– Microwire compatible
– Multiple-master, single-master, and slave modes
— Up to eight TDM interfaces (4 on the MPC8255)
– Supports two groups of four TDM channels for a total of eight TDMs
– 2,048 bytes of SI RAM
– Bit or byte resolution
– Independent transmit and receive routing, frame synchronization
– Supports T1, CEPT, T1/E1, T3/E3, pulse code modulation highway, ISDN basic rate, ISDN primary rate, Freescale interchip digital link (IDL), general circuit interface (GCI), and user-defined TDM serial interfaces
— Eight independent baud rate generators and 20 input clock pins for supplying clocks to FCCs, SCCs, SMCs, and serial channels
— Four independent 16-bit timers that can be interconnected as two 32-bit timers