Motorola MVME2301, Installation And Use Manual

Page: 43 / 167

MVME230x
2-3
2
ABT (S1)
When activated by software, the Abort switch,
ABT
, can generate an
interrupt signal from the base board to the processor at a user-
programmable level. The interrupt is normally used to abort
program execution and return control to the debugger firmware
located in the MVME230x Flash memory. The interrupt signal
reaches the processor module via ISA bus interrupt line IRQ8
∗ . The
signal is also available from the general purpose I/O port, which
allows software to poll the Abort switch after an IRQ8* interrupt and verify
that it has been pressed.
The interrupter connected to the
ABT
switch is an edge-sensitive
circuit, filtered to remove switch bounce.
RST (S2)
The Reset switch,
RST
, resets all onboard devices and causes
HRESET* to be asserted in the MPC603 or MPC604. It also drives a
SYSRESET* signal if the MVME230x VME processor module is the
system controller.
The Universe ASIC includes both a global and a local reset driver.
When the Universe operates as the VMEbus system controller, the
reset driver provides a global system reset by asserting the VMEbus
signal SYSRESET*. A SYSRESET* signal may be generated by the
RESET switch, a power-up reset, a watchdog timeout, or by a
control bit in the Miscellaneous Control Register (MISC_CTL) in the
Universe ASIC. SYSRESET* remains asserted for at least 200 ms, as
required by the VMEbus specification.
Similarly, the Universe ASIC supplies an input signal and a control
bit to initiate a local reset operation. By setting a control bit,
software can maintain a board in a reset state, disabling a faulty
board from participating in normal system operation. The local
reset driver is enabled even when the Universe ASIC is not system
controller. Local resets may be generated by the
RST
switch, a
power-up reset, a watchdog timeout, a VMEbus SYSRESET*, or a
control bit in the MISC_CTL register.