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VMEchip2

from the retry and the board does not lose its turn on the VMEbus. For this reason, it is recommended that this bit remain low.

NOELBBSY When this bit is high, the early release feature of bus busy feature on the VMEbus is disabled. The VMEchip2 drives BBSY* low whenever VMEbus AS* is low. When this bit is low, the early release feature of bus busy feature on the VMEbus is not disabled.

DISMST When this bit is high, the VME LED on the MVME172 is lit when local bus reset is asserted or the VMEchip2 is driving local bus busy. When this bit is low, the VME LED on the MVME172 is lit when local bus reset is asserted, the VMEchip2 is driving local bus busy, or the VMEchip2 is driving the VMEbus address strobe.

DISSRAM When this bit is high, the SRAM decoder in the VMEchip2 is disabled. When this bit is low, the SRAM decoder in the VMEchip2 is enabled. Because the SRAM decoder in the VMEchip2 is not used on the MVME172, this bit must be set.

REVEROM This function is not used on the MVME172. This bit must not be set.

MPIRQEN This function is not used on the MVME172. This bit must not be set.

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