Motorola MVME177 manual Sysreset

Software Initialization

❏Pressing the front panel RESET switch (if the system controller function is disabled)

❏Asserting a bit in the board control register in the GCSR

❏SYSRESET*

❏Power-up reset

Note The GCSR allows a VMEbus master to reset the local bus. This feature is very dangerous and should be used with caution. The local reset feature is a partial system reset, not a complete system reset such as power-up reset or SYSRESET*. When the local bus reset signal is asserted, a local bus cycle may be aborted. The VMEchip2 is connected to both the local bus and the VMEbus and if the aborted cycle is bound for the VMEbus, erratic operation may result. Communications between the local processor and a VMEbus master should use interrupts or mailbox locations; reset should not be used in normal communications. Reset should be used only when the local processor is halted or the local bus is hung and reset is the last resort.

Any VMEbus access to the MVME177 while it is in the reset state is ignored. If a global bus timer is enabled, a bus error is generated.

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