Motorola CPCI-6115 Manuel de service télécharger pdf (Page 33)

Chapter 2 System Architecture

CPX8216 and CPX8216T Installation and Use (6806800A52C)

Board Insertion and Extraction Features

The PICMG Specification details software and hardware features in order to support hot-

swapping of I/O boards. Hardware features include:

■ Staged pins that control voltages when inserting or extracting boards

■ BD_SEL#, HEALTHY#, and ENUM# signals

■ Hot swap control status register

Staged Pins

The PICMG CompactPCI Hot Swap Specification provides for three separate pin lengths in

order to control the insertion and extraction voltages and to notify the system when boards are

inserted or extracted.

The longest pins, which include VCC pins and GND pins, are the first to mate during the

insertion process and the last to break contact during extraction. These pins are used to supply

power to pre-charge the PCI interface signals to a neutral state before they contact the bus. This

pre-charging serves to minimize the capacitive effects of the board as it makes or breaks

contact with the bus.

The medium-length pins carry PCI and other signal traffic.

The shortest pins are used to assert signals, including BD_SEL#. During insertion, the

BD_SEL# signal enables the board to attach to the local PCI bus. On extraction, it causes the

board to logically and electrically disconnect from the PCI bus before the bus pins physically

break contact with the bus.

BD_SEL#

BD_SEL# is asserted by one of the pins that mate last on insertion and break first on extraction.

On insertion, the signal tells the board to connect to the PCI bus. On extraction, this pin breaks

first causing the board to logically and electrically disconnect from the PCI bus before the PCI

bus pins physically break contact with the bus.

ENUM#

An ENUM interrupt is generated when a board is hot inserted into the CPX8216 chassis, or

when an operator trips the board microswitch by raising its ejector handles. The signal informs

the active CPU that the status of a board has changed. The CPU then identifies the board by

polling the INSert and EXTract bits in all of the boards’ Control Status Registers.

Hot Swap Control Status Register (CSR)

The CPX8216 supports hot swap CompactPCI cards with the standard control status register

defined by the PICMG Hot Swap Specification. The register is visible in PCI configuration space

and provides hot swap control and status bits INS and EXT. The INS signal is set when ENUM#

is asserted by a board being inserted into the chassis. The EXT signal is asserted when

ENUM# is asserted by an operator triggering the microswitch in the board handles. The host

also uses these bits to acknowledge and deassert ENUM#.

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Motorola CPCI-6115 Manuel de service Page 33