Local Reset Operation - Motorola MVME162 User Manual

Local Reset Operation

Local reset (LRST) is a subset of system reset (SRST). Local reset can be
generated five ways:
Expiration of the watchdog timer
Pressing the front panel
disabled)
By asserting a bit in the board control register in the GCSR
By SYSRESET*
By powerup reset.
N The GCSR allows a VMEbus master to reset the local bus.
ote
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 powerup 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 MVME162 while it is in the reset state is ignored. If
a global bus timer is enabled, a bus error is generated.
MVME162/D2
switch (if the system controller function is
RESET
Software Initialization
3-25
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