RAM 6.0 BUX II Series Guía de usuario descargar pdf (Pagina 120)

VxWorks

BSP Developer’s Guide, 6.0

112

With separate drivers for different functional areas, users can scale out support for

functional areas that are not used by their application.

SCSI-2 Devices

The VxWorks SCSI-2 subsystem consists of the following components:

■

SCSI libraries, an architecture-independent component

■

SCSI controller driver, an architecture-specific component

■

SCSI-2 subsystem initialization code, a board-specific component

Although the BSP is responsible for the initialization code, you must maintain the

structures internal to the library code and the controller. For information on how

to do this, see the VxWorks Device Driver Developer’s Guide.

Troubleshooting and Debugging

This section provides several suggestions for troubleshooting techniques and

debugging shortcuts.

SCSI Cables and Termination

A poor cable connection or poor SCSI termination is one of the most common

sources of erratic behavior, of the VxWorks target hanging during SCSI execution,

and even of unknown interrupts. The SCSI bus must be terminated at both ends,

but make sure that no device in the middle of the daisy chain has pull-up

terminator resistors or any other form of termination.

Data Coherency Problems

Data coherency problems usually occur in hardware environments where the CPU

supports data caching. First, disable the data caches and verify that data

corruption is occurring. If the problem disappears with the caches disabled, the

coherency problem is related to caches. (Caches can usually be turned off in the

BSP by #undef

USER_D_CACHE_ENABLE.) In order to further troubleshoot the

data cache coherency problem, use the cacheDmaMalloc( ) routine in the driver

for all memory allocations. However, if hardware snooping is enabled then the

problem may lie elsewhere.

1 2 ... 115 116 117 118 119 120 121 122 123 124 125 ... 188 189

Sin comentarios

RAM 6.0 BUX II Series Guía de usuario Pagina 120