2 Features
Figure 1 is a block diagram of the MPC850, showing its major components and the relationships among
those components:
The following list summarizes the main features of the MPC850:
• Embedded single-issue, 32-bit MPC8xx core (implementing the PowerPC architecture) with
thirty-two 32-bit general-purpose registers (GPRs)
— Performs branch folding and branch prediction with conditional prefetch, but without
conditional execution
— 2-Kbyte instruction cache and 1-Kbyte data cache (Harvard architecture)
– Caches are two-way, set-associative
– Physically addressed
– Cache blocks can be updated with a 4-word line burst
– Least-recently used (LRU) replacement algorithm
– Lockable one-line granularity
— Memory management units (MMUs) with 8-entry translation lookaside buffers (TLBs) and
fully-associative instruction and data TLBs
— MMUs support multiple page sizes of 4 Kbytes, 16 Kbytes, 256 Kbytes, 512 Kbytes, and
8 Mbytes; 16 virtual address spaces and eight protection groups
Advanced on-chip emulation debug mode
Data bus dynamic bus sizing for 8, 16, and 32-bit buses
— Supports traditional 68000 big-endian, traditional x86 little-endian and modified little-endian
memory systems
— Twenty-six external address lines
Completely static design (0–80 MHz operation)
System integration unit (SIU)
— Hardware bus monitor
— Spurious interrupt monitor
— Software watchdog
— Periodic interrupt timer
— Low-power stop mode
— Clock synthesizer
— Decrementer, time base, and real-time clock (RTC) from the PowerPC architecture
— Reset controller
— IEEE 1149.1 test access port (JTAG)
Memory controller (eight banks)
— Glueless interface to DRAM single in-line memory modules (SIMMs), synchronous DRAM
(SDRAM), static random-access memory (SRAM), electrically programmable read-only
memory (EPROM), flash EPROM, etc.
— Memory controller programmable to support most size and speed memory interfaces
— Boot chip-select available at reset (options for 8, 16, or 32-bit memory)
— Variable block sizes, 32 Kbytes to 256 Mbytes
— Selectable write protection
— On-chip bus arbiter supports one external bus master
— Special features for burst mode support
General-purpose timers
— Four 16-bit timers or two 32-bit timers
— Gate mode can enable/disable counting
— Interrupt can be masked on reference match and event capture
Interrupts
— Eight external interrupt request (IRQ) lines
— Twelve port pins with interrupt capability
— Fifteen internal interrupt sources
— Programmable priority among SCCs and USB
— Programmable highest-priority request
Single socket PCMCIA-ATA interface
— Master (socket) interface, release 2.1 compliant
— Single PCMCIA socket
— Supports eight memory or I/O windows
Communications processor module (CPM)
— 32-bit, Harvard architecture, scalar RISC communications processor (CP)
— Protocol-specific command sets (for example, GRACEFUL STOP TRANSMIT stops transmission
after the current frame is finished or immediately if no frame is being sent and CLOSE RXBD
closes the receive buffer descriptor)
— Supports continuous mode transmission and reception on all serial channels
— Up to 8 Kbytes of dual-port RAM
— Twenty serial DMA (SDMA) channels for the serial controllers, including eight for the four
USB endpoints
— Three parallel I/O registers with open-drain capability
Four independent baud-rate generators (BRGs)
— Can be connected to any SCC, SMC, or USB
— Allow changes during operation
— Autobaud support option
Two SCCs (serial communications controllers)
— Ethernet/IEEE 802.3, supporting full 10-Mbps operation
— HDLC/SDLC™(all channels supported at 2 Mbps)
— HDLC bus (implements an HDLC-based local area network (LAN))
— Asynchronous HDLC to support PPP (point-to-point protocol)
— AppleTalk®
— Universal asynchronous receiver transmitter (UART)
— Synchronous UART
— Serial infrared (IrDA)
— Totally transparent (bit streams)
— Totally transparent (frame based with optional cyclic redundancy check (CRC))
• QUICC multichannel controller (QMC) microcode features
— Up to 64 independent communication channels on a single SCC
— Arbitrary mapping of 0–31 channels to any of 0–31 TDM time slots
— Supports either transparent or HDLC protocols for each channel
— Independent TxBDs/Rx and event/interrupt reporting for each channel
• One universal serial bus controller (USB)
— Supports host controller and slave modes at 1.5 Mbps and 12 Mbps
• Two serial management controllers (SMCs)
— UART
— Transparent
— General circuit interface (GCI) controller
— Can be connected to the time-division-multiplexed (TDM) channel
• One serial peripheral interface (SPI)
— Supports master and slave modes
— Supports multimaster operation on the same bus
• One I2C® (interprocessor-integrated circuit) port
— Supports master and slave modes
— Supports multimaster environment
• Time slot assigner
— Allows SCCs and SMCs to run in multiplexed operation
— Supports T1, CEPT, PCM highway, ISDN basic rate, ISDN primary rate, user-defined
— 1- or 8-bit resolution
— Allows independent transmit and receive routing, frame syncs, clocking
— Allows dynamic changes
— Can be internally connected to four serial channels (two SCCs and two SMCs)
• Low-power support
— Full high: all units fully powered at high clock frequency
— Full low: all units fully powered at low clock frequency
— Doze: core functional units disabled except time base, decrementer, PLL, memory controller,
real-time clock, and CPM in low-power standby
— Sleep: all units disabled except real-time clock and periodic interrupt timer. PLL is active for
fast wake-up
— Deep sleep: all units disabled including PLL, except the real-time clock and periodic interrupt
timer
— Low-power stop: to provide lower power dissipation
— Separate power supply input to operate internal logic at 2.2 V when operating at or below
25 MHz
— Can be dynamically shifted between high frequency (3.3 V internal) and low frequency (2.2 V
internal) operation
Debug interface
— Eight comparators: four operate on instruction address, two operate on data address, and two
operate on data
— The MPC850 can compare using the =, ≠, <, and > conditions to generate watchpoints
— Each watchpoint can generate a breakpoint internally
3.3-V operation with 5-V TTL compatibility on all general purpose I/O pins.