Motorola MVME1X7P manual Error Conditions, VMEchip2, Bus Error Processing

Models: MVME1X7P

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Error Conditions

A hardware error occurs on the VMEbus.

A VMEbus slave reports an access error (such as parity error).

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VMEchip2

An 8- or 16-bit write to the LCSR in the VMEchip2 ASIC causes a local BERR.

Bus Error Processing

Because different conditions can cause bus error exceptions, the software must be able to distinguish the source. To aid in this, status registers are provided for every Local Bus master. The next section describes the various causes of bus error and the associated status registers.

Generally, the bus error handler can interrogate the status bits and proceed with the result. However, an interrupt may occur during the execution of the bus error handler (before an instruction can write to the status register to raise the interrupt mask). If the interrupt service routine causes a second bus error, the status that indicates the source of the first bus error may be lost. Application software must take this possibility into account.

Error Conditions

This section lists the various error conditions that are reported by the single-board computer hardware. A subheading identifies each error condition; a standard format provides the following information:

Description of the error

How notification of the error is made

Status register(s) containing information about the error

Comments pertaining to the error

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Page 81
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Motorola MVME1X7P manual Error Conditions, VMEchip2, Bus Error Processing