Plug and Play for IEEE 1394
This section summarizes the Plug and Play requirements for IEEE 1394 peripheral devices and PC host controllers.
9. Plug and Play devices demonstrate interoperability with other devices
All devices must support Plug and Play for intended applications in both a minimal and an extended bus configuration. A minimal configuration is the minimum number of devices necessary to demonstrate the primary application of the device. An extended configuration is an advanced application with at least two devices added to the minimal configuration. The added devices can be extraneous to the application.
The following is a summary of compliance testing guidelines for this requirement:
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Intended applications must be documented before testing.
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Both test configurations must consist of a core matrix of stable devices that have demonstrated full interoperability in the absence of the test device. To be included in the core test matrix, a device must have demonstrated compliance of its PHY, Link, and Transaction layers as specified in the IEEE 1394-1995 standard.
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The core matrix of devices must be established by an independent agency such as the 1394 Trade Association, with actual testing performed by an independent third party or as part of an industry compatibility workshop.
10. Topology faults do not cause the bus to fail
Standard IEEE 1394 protocols have been defined to eliminate topology faults. However, to ensure correct implementation, the following items describe test criteria for industry compatibility workshops. In each case, connection or removal of a device must not stall the bus, but the faulting device might not function. The PC must detect each fault. The test criteria include the following:
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Surprise removal. All isochronous-capable devices must support the Connection Management Protocol specified in IEC 1883 (or the most recent specification) in order to resume streaming connections following a bus reset and to de-allocate channels upon surprise removal of a device.
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Safe removal. All devices that provide a front-panel power switch must signal the operating system in response to a local shut-down request (that is, hot unplugging) in order to allow safe removal. Safe removal requires that the end user monitor the PC bus manager’s response to the request before removing the device.
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Greater than 16 cable hops. If the user extends the bus beyond 16 hops (that is, device-to-device daisy-chain connections), the total distance end-to-end approaches 16 × 4.5 meters = 72 meters. This distance exceeds propagation delay times for fair arbitration timing, potentially starving a node on a heavily loaded bus. Cable lengths must not exceed 4.5 meters. In this scenario, the PC is acting as bus manager and must detect the topology fault and provide a warning message to the user.
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Greater than 63 devices on a local IEEE 1394 bus. If the 63-device limit is exceeded, the 64th and later devices will be assigned a physical ID of 63. The 64th device must be detected by the PC bus manager and must provide a warning message to the user.
11. Removable media devices support media status notification
Removable media devices must use an electronic switch to notify the PC in the event of media change requests. This is necessary to enable device applications to lock, unlock, and eject media.
12. Devices that can initiate peer-to-peer communications also support remote programming
To enhance systems integration, all devices capable of initiating peer-to-peer communications must also support a programming language that enables remote control for PC applications. This allows a third device, such as a PC or device controller, to initiate data transmission between two devices.