Motorola MVME1X7P User Manual
2-18
Computer Group Literature Center Web Site
VMEchip2
2
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.
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
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.
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
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