Error Management; Selftest Operation; System Interrupt - HP 30240A Installation And Service Manual

Error Management
Selftest Operation
System Interrupt
Principlc~
of Operation
3-8
The LANIC detects command, system, and network errors, takes recovery action
when appropriate, and reports status to the host. Command format errors are
simply reported to the host, but do not result in any interruption of operations in
progress. The LANIC attempts recovery of certain errors, such as ThickMAU
jabber, and if recovery is successful, the LANIC reports the recovery to the host
for logging, and continues operation. When the LANIC detects a
non-recoverable error, such as a system memory error, it aborts all operations in
progress, reports the nature of the error to the host via the system interrupt
mechanism. and waits for further action by the host.
The LANIC executes a self-contained selftest program on system reset. or under
host software control. Additionally. self test can be initiated via a switch on the
card. or
by
power-on. The LANIC selftest program tests a portion of the LANIC
hardware. The selftest result code is displayed visually on the LANIC card (see
Chapter 4), and can be programmatically read by the host via a channel register
dedicated to selftest result codes.
The LANIC can request a host software interrupt via two pseudo-device
interrupts. When the host issues the OBn command to the LANIC, the data
returned has either a zero or a one in bit 15. corresponding to the interrupting
device number. Device number zero corresponds to the interrupt called SINTRO.
and device number one corresponds to the interrupt called SINTRI. If both
interrupt requests, SINTRO and SINTRI. are active simultaneously the interrupt
code for SINTRO is returned.
Operation of the LANIC IRQ (Interrupt Request) is as follows:
If either or both of SINTRO and SINTRI are set and the interrupt mask.
MASKF. is set. then the channel asserts the IRQ line on the backplane.
Eventually, the host detects that IRQ is asserted and invokes the microcode
routine to handle interrupts. This microcode performs an IPOLL to determine
which channel(s) are requesting. and then an OBn to determine which device
on the channel to service. After determining which channel and device to
service. the microcode issues a WIOC command to clear SINTR, and
dispatches the appropriate software interrupt routine.