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22. Glossary

22.1 ABI - Application Binary Interface

The convention for register usage and C linkage commonly used on desktop PowerPC machines. Similar, but not identical to the EABI.

22.2 BDM - Background Debug Mode

An on-chip debugging interface, largely eliminating the need for expensive In Circuit Emulators.

22.3 CPM - Communications Processor Module

The magic communications co-processor in Motorola PowerQUICC devices. It contains SCCs and SMCs , and performs SDMA and IDMA.

22.4 CPU - Central Processor Unit

Depending on the context, this may refer to the PowerPC core itself, or the physical processor device (including CPM, SIU, packaging etc) as a single unit.

22.5 DMA - Direct Memory Access

A form a data transfer directly between memory and a peripheral or between memory and memory, without normal program intervention.

22.6 EABI - Embedded Application Binary Interface

The convention for register usage and C linkage commonly used on embedded PowerPC machines, derived from the ABI.

22.7 FEC - Fast Ethernet Controller

The 100 Mbps (100Base) Ethernet controller, present on 'T' devices such as the 860T and 855T.

22.8 IDMA - Independent DMA

A general purpose DMA engine with relatively limited throughput provided by the microcoded CPM, for use with external peripherals or memory-to-memory transfers.

22.9 MII - Media Independent Interface

The IEEE Ethernet standard control interface used to communicate between the on-chip Ethernet controller and the external PHY.

22.10 MMU - Memory Management Unit

CPU component which maps kernel- and user-space virtual addresses to physical addresses, and is an integral part of Linux kernel operation.

22.11 PHY - Physical Interface

The IEEE Ethernet standard interface between the external physical layer transceiver and the on-chip ethernet controller in a PowerQUICC device. Often used to refer to the external transceiver itself, the PHY is controlled more or less transparently to software via the MII.

22.12 SCC - Serial Communications Controller

The high performance module(s) within the CPM which implement the lowest layer of various serial protocols, such as Asynchronous serial ( UART), 10 Mbps Ethernet, HDLC etc.

22.13 SDMA - Serial DMA

DMA used to transfer data to and from the SCCs.

22.14 SIU - System Interface Unit

Provides much of the external interfacing logic. It's the other major module on Motorola PowerQUICC devices alongside the CPU core and CPM.

22.15 SMC - Serial Management Controller

A lower performance version of the SCCs with more limited functionality, particularly useful for serial debug ports and low throughput serial protocols.

22.16 UART - Universal Asynchronous Receiver Transmitter

Generically, this refers to any device capable of implementing a variety of asynchronous serial protocols, such as RS-232, HDLC and SDLC. In this context, it refers to the operating mode of the SCCs which provides this functionality.

22.17 UPM - User Programmable Machine

A highly flexible bus interfacing machine unit allowing external peripherals with an extremely wide variety of interfacing requirements to be connected directly to the CPU.


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