Communications Processor Module (CPM) is a component of

Motorola 68000 family The Motorola 68000 series (also known as 680x0, m68000, m68k, or 68k) is a family of 32-bit complex instruction set computer (CISC) microprocessors. During the 1980s and early 1990s, they were popular in personal computers and workstations and w ...

( QUICC) or Motorola/

Freescale Semiconductor Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, embed ...

PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., App ...

Power ISA Power ISA is a reduced instruction set computer (RISC) instruction set architecture (ISA) currently developed by the OpenPOWER Foundation, led by IBM. It was originally developed by IBM and the now-defunct Power.org industry group. Power IS ...

(

PowerQUICC PowerQUICC is the name for several PowerPC- and Power ISA-based microcontrollers from Freescale Semiconductor. They are built around one or more PowerPC cores and the Communications Processor Module ( QUICC Engine) which is a separate RISC core sp ...

) microprocessors designed to provide features related to imaging and communications. A microprocessor can delegate most of the input/output processing (for example sending and receiving data via the serial interface) to the Communications Processor Module and the microprocessor does not have to perform those functions itself. Some input/output functions require quick response from the processor, for example due to precise timing requirements during data transmission. With CPM performing those operations, the main microprocessor is free to perform other tasks. The CPM features its own

RISC In computer engineering, a reduced instruction set computer (RISC) is a computer designed to simplify the individual instructions given to the computer to accomplish tasks. Compared to the instructions given to a complex instruction set comput ...

microcontroller (Communication Processor), separate from the actual

Central Processing Unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

IP core In electronic design, a semiconductor intellectual property core (SIP core), IP core, or IP block is a reusable unit of logic, cell, or integrated circuit layout design that is the intellectual property of one party. IP cores can be licensed to ...

. The RISC microcontroller communicates with the core using

dual-ported RAM Dual-ported RAM (DPRAM) is a type of random-access memory that allows multiple reads or writes to occur at the same time, or nearly the same time, unlike single-ported RAM which allows only one access at a time. Video RAM or VRAM is a common for ...

, special command, configuration and event registers as well as via

interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...

s. Motorola 68302 Integrated Multiprotocol Processor featured a RISC processor controlled either by a

microcode In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a laye ...

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

or by downloadable firmware. Various forms of microcode were shipped for different applications, for example to support

Signaling System 7 Signalling System No. 7 (SS7) is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down telephone calls in most parts of the world-wide public switched telephone network (PSTN). The protocol also perform ...

communications or

Centronics Centronics Data Computer Corporation was an American manufacturer of computer printers, now remembered primarily for the parallel interface that bears its name, the Centronics connector. History Foundations Centronics began as a division ...

parallel interface. Motorola 68360 QUICC was the first design to feature Communications Processor Module, offering microcode for SS7 and

ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...

applications. Specifications of the microcontroller programming interface were generally not shipped to customers. It was possible to run 68360 in ''slave mode'' and to use only CPM part of the chip, for example in the M68360QUADS-040 board, where 68040 CPU (master) is coupled with 68360 CPM (slave), with CPU of 68360 processor being disabled. CPM was used later in the

series of

- and

-based processors. Early designs, like MPC860, used virtually the same CPM as the previous 68360 QUICC processors.Freescale Application Not
AN2051 Porting Code from MC68360 to MPC860
1996 Typical features of the CPM include: *

Medium access control In IEEE 802 LAN/MAN standards, the medium access control (MAC, also called media access control) sublayer is the layer that controls the hardware responsible for interaction with the wired, optical or wireless transmission medium. The MAC sublay ...

(MAC), * Communication interfaces with serial communication controllers (SCC), serial management controllers (SMC),

Universal Serial Bus Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

I²C I2C (Inter-Integrated Circuit, ), alternatively known as I2C or IIC, is a synchronous, multi-controller/multi-target (master/slave), packet switched, single-ended, serial communication bus invented in 1982 by Philips Semiconductors. It is wide ...

and

Serial Peripheral Interface Bus The Serial Peripheral Interface (SPI) is a synchronous serial communication interface specification used for short-distance communication, primarily in embedded systems. The interface was developed by Motorola in the mid-1980s and has become a ...

attachment, *

Direct memory access Direct memory access (DMA) is a feature of computer systems and allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU). Without DMA, when the CPU is using programmed input/output, it is t ...

(DMA) circuitry, interrupt controller, time-slot assigner and

baud rate In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modul ...

generators.

Notes

References

* Freescale Semiconducto
MC68360 QUad Integrated Communications Controller User's Manual
1995. * Freescale Semiconducto
PowerPC MPC823 Reference Manual
revision 1, section 1.2.3 ''Communication Processor Module'', page 1–9, 2000. * Freescale Semiconducto
Application Note 2045: CPM/CPU Interaction
* Freescale Semiconducto
Application Note 2050: QUICC/PowerQUICC Differences
{{NXP Semiconductors PowerPC microprocessors Motorola microprocessors Freescale Semiconductor