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Communication Processor Module
Communications Processor Module (CPM) is a component of Motorola 68000 family ( QUICC) or Motorola/Freescale Semiconductor PowerPC/Power ISA (PowerQUICC) 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 microcontroller (Communication Processor), separate from the actual Central Processing Unit IP core. The RISC microcontroller communicates with the core using dual-ported RAM, special command, configuration and event registers as well as via inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 were the primary competitors of Intel's x86 microprocessors. They were best known as the processors used in the early Apple Macintosh, the Sharp X68000, the Commodore Amiga, the Sinclair QL, the Atari ST, the Sega Genesis (Mega Drive), the Capcom System I (Arcade), the AT&T UNIX PC, the Tandy Model 16/16B/6000, the Sun Microsystems Sun-1, Sun-2 and Sun-3, the NeXT Computer, NeXTcube, NeXTstation, and NeXTcube Turbo, the Texas Instruments TI-89/TI-92 calculators, the Palm Pilot (all models running Palm OS 4.x or earlier) and the Space Shuttle. Although no modern desktop computers are based on processors in the 680x0 series, derivative processors are still widely used in embedded systems. Motorola ceased development of the 680x0 series arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 performs number translation, local number portability, prepaid billing, Short Message Service (SMS), and other services. The protocol was introduced in the Bell System in the United States by the name ''Common Channel Interoffice Signaling'' in the 1970s for signalling between No. 4ESS switch and No. 4A crossbar toll offices. In North America SS7 is also often referred to as ''Common Channel Signaling System 7'' (CCSS7). In the United Kingdom, it is called ''C7'' (CCITT number 7), ''number 7'' and ''Common Channel Interoffice Signaling 7'' (CCIS7). In Germany, it is often called ''Zentraler Zeichengabekanal Nummer 7'' (ZZK-7). The SS7 protocol is defined for international use by the Q.700-series recommendations of 1988 by the ITU-T. Of the many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PowerPC Microprocessors
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– IBM–Motorola alliance, known as AIM. PowerPC, as an evolving instruction set, has been named Power ISA since 2006, while the old name lives on as a trademark for some implementations of Power Architecture–based processors. PowerPC was the cornerstone of AIM's PReP and Common Hardware Reference Platform (CHRP) initiatives in the 1990s. Originally intended for personal computers, the architecture is well known for being used by Apple's Power Macintosh, PowerBook, iMac, iBook, eMac, Mac Mini, and Xserve lines from 1994 until 2005, when Apple migrated to Intel's x86. It has since become a niche in personal computers, but remains popular for embedded and high-performance processors. Its use in 7th generation of video game consoles and embedde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbol Rate
In a digitally modulated signal or a line code, symbol rate, modulation rate or baud rate is the number of symbol changes, waveform changes, or signaling events across the transmission medium per unit of time. The symbol rate is measured in ''baud'' (Bd) or ''symbols per second''. In the case of a line code, the symbol rate is the pulse rate in pulses per second. Each symbol can represent or convey one or several bits of data. The symbol rate is related to the ''gross bit rate'', expressed in ''bits per second''. Symbols A symbol may be described as either a pulse in digital baseband transmission or a tone in passband transmission using modems. A symbol is a waveform, a state or a significant condition of the communication channel that ''persists'', for a fixed period of time. A sending device places symbols on the channel at a fixed and known symbol rate, and the receiving device has the job of detecting the sequence of symbols in order to reconstruct the transmitted data. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time-division Multiplexing
Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern. This method transmits two or more digital signals or analog signals over a common channel. It can be used when the bit rate of the transmission medium exceeds that of the signal to be transmitted. This form of signal multiplexing was developed in telecommunications for telegraphy systems in the late 19th century, but found its most common application in digital telephony in the second half of the 20th century. History Time-division multiplexing was first developed for applications in telegraphy to route multiple transmissions simultaneously over a single transmission line. In the 1870s, Émile Baudot developed a time-multiplexing system of multiple Hughes telegraph machines. In 1944, the Britis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU first initiates the transfer, then it does other operations while the transfer is in progress, and it finally receives an interrupt from the DMA controller (DMAC) when the operation is done. This feature is useful at any time that the CPU cannot keep up with the rate of data transfer, or when the CPU needs to perform work while waiting for a relatively slow I/O data transfer. Many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in multi-core processors. Computers that have DMA channels can trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ''de facto'' standard. Typical applications include Secure Digital cards and liquid crystal displays. SPI devices communicate in full duplex mode using a master-slave architecture usually with a single master (though some Atmel and Silabs devices support changing roles on the fly depending on an external (SS) pin). The master (controller) device originates the frame for reading and writing. Multiple slave-devices may be supported through selection with individual chip select (CS), sometimes called slave select (SS) lines. Sometimes SPI is called a ''four-wire'' serial bus, contrasting with three-, two-, and one-wire serial buses. The SPI may be accurately described as a synchronous serial interface, but it is different from the Sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 widely used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication. Several competitors, such as Siemens, NEC, Texas Instruments, STMicroelectronics, Motorola, Nordic Semiconductor and Intersil, have introduced compatible I2C products to the market since the mid-1990s. System Management Bus (SMBus), defined by Intel in 1995, is a subset of I2C, defining a stricter usage. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern I2C systems incorporate some policies and rules from SMBus, sometimes supporting both I2C and SMBus, requiring only minimal reconfiguration either by commanding or output pin use. Applications I2C is appropriate for peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 variety of USB hardware exists, including 14 different connector types, of which USB-C is the most recent and the only one not currently deprecated. First released in 1996, the USB standards are maintained by the USB Implementers Forum (USB-IF). The four generations of USB are: USB 1.''x'', USB 2.0, USB 3.''x'', and USB4. Overview USB was designed to standardize the connection of peripherals to personal computers, both to communicate with and to supply electric power. It has largely replaced interfaces such as serial ports and parallel ports, and has become commonplace on a wide range of devices. Examples of peripherals that are connected via USB include computer keyboards and mice, video cameras, printers, portable media players, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Communication Controller
A universal synchronous and asynchronous receiver-transmitter (USART, programmable communications interface or PCI) is a type of a serial interface device that can be programmed to communicate asynchronously or synchronously. See universal asynchronous receiver-transmitter (UART) for a discussion of the asynchronous capabilities of these devices. Purpose and history The USART's synchronous capabilities were primarily intended to support synchronous protocols like IBM's synchronous transmit-receive (STR), binary synchronous communications (BSC), synchronous data link control (SDLC), and the ISO-standard high-level data link control (HDLC) synchronous link-layer protocols, which were used with synchronous voice-frequency modems. These protocols were designed to make the best use of bandwidth when modems were analog devices. In those times, the fastest asynchronous voice-band modem could achieve at most speeds of 300bit/s using frequency-shift keying (FSK) modulation, while synchronou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 sublayer and the logical link control (LLC) sublayer together make up the data link layer. The LLC provides flow control and multiplexing for the logical link (i.e. EtherType, 802.1Q VLAN tag etc), while the MAC provides flow control and multiplexing for the transmission medium. These two sublayers together correspond to layer 2 of the OSI model. For compatibility reasons, LLC is optional for implementations of IEEE 802.3 (the frames are then "raw"), but compulsory for implementations of other IEEE 802 physical layer standards. Within the hierarchy of the OSI model and IEEE 802 standards, the MAC sublayer provides a control abstraction of the physical layer such that the complexities of physical link control are invisible to the LLC and upper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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