1

Board Description and Memory Maps

Generally, the bus error handler can interrogate the status bits and proceed with the result. However, an interrupt can happen 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. The software must be written to deal with this.

Description of Error Conditions on the MVME172

This section list the various error conditions that are reported by the MVME172 hardware. A subsection heading identifies each type of error condition. A standard format gives a description of the error, indicates how notification of the error condition is made, indicates which status register(s) have information about the error, and concludes with some comments pertaining to each particular error.

MPU Parity Error

Note The 400/500_Series MVME172 models do not contain parity DRAM.

Description:

A DRAM parity error.

MPU Notification:

TEA is asserted during an MPU DRAM access.

Status:

Bit 9 of the MPU Status and DMA Interrupt Count Register in the

VMEchip2 at address $FFF40048.

Comments:

After memory has been initialized, this error normally indicates a hardware problem.

1-50

Computer Group Literature Center Web Site

Page 68
Image 68
Motorola manual Description of Error Conditions on the MVME172, MPU Parity Error