Motorola MVME1X7P manual Local Bus Interrupter and Interrupt Handler, Reset Driver, Dmac done

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VMEchip2

In addition to the VMEbus timer, the chip contains a local bus timer. This timer asserts the local TEA when the local bus cycle maintained in its asserted state for longer that the programmed time-out period. This timer can be enabled or disabled under software control. The time-out period can be programmed for 8, 64, or 256 seconds.

Reset Driver

The chip includes both a global and a local reset driver. When the chip operates as the VMEbus system controller, the reset driver provides a global system reset by asserting the VMEbus signal SYSRESET∗. A SYSRESET∗ may be generated by the RESET switch, a power-up reset, a watch dog timeout, or by a control bit in the LCSR. SYSRESET∗ remains asserted for at least 200 msec, as required by the VMEbus specification.

Similarly, the chip provides an input signal and a control bit to initiate a local reset operation.

The local reset driver is enabled even when the chip is not the system controller. A local reset may be generated by the RESET switch, a power up reset, a watch dog time-out, a VMEbus SYSRESET∗ signal, or a control bit in the GCSR.

Local Bus Interrupter and Interrupt Handler

There are 31 interrupt sources in the VMEchip2 ASIC:

VMEbus ACFAIL interrupter	Tick timer 2-1
ABORT switch	DMAC done
VMEbus SYSFAIL interrupter	GCSR SIG3-0
Write post bus error	GCSR location monitor 1-0
External input	Software interrupts 7-0
VMEbus IRQ1 edge-sensitive interrupter	VMEbus IRQ7-1 interrupts
VMEchip2 VMEbus interrupter acknowledge

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