SBS Technologies 466-1, Руководство по оборудованию

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Model 466-1 Adapter
Common Problems And Solutions 73
9.2.2 Local Status Register Bit 6: Remote VMEbus Error
Any remote VMEbus access that terminates improperly may cause a VMEbus
error (
BERR) . The BERR signal can be asserted by the slave device or a bus
timer. When asserted by a slave, it indicates that an error occurred during the
access cycle. When asserted by the bus timer, VMEbus mastership was
granted but the target device took longer than 48 to 54
µ
sec (the de facto
standard) to respond. If BERR occurred during a remote VMEbus access, this
bit is set. It will not clear until reset via the Local Command Register reset
mechanism.
Common causes of remote VMEbus errors:
An incorrect VMEbus address.
An incorrect VMEbus address modifier.
A remote node access performed to a slow slave device that takes longer
than 48 - 54
µ
sec to respond.
A VMEbus interrupt acknowledge cycle for which no interrupting card
responds.
Device dependent VMEbus errors:
An incorrect data size. For example, an attempt to perform a D16
transfer to a D08 device.
A read performed from a write-only location, or a write performed to a
read-only location.
A parity error was detected internal to a VMEbus memory card. The
VMEbus memory card may not generate DTACK if a parity error is
detected. This typically occurs when the memory location is read before
being written (initialized) at least once.