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Principles of Operation
Self-Test Operation
The LANIC executes a self -contained self -test 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 self -test
program tests a portion of the LANIC hardware. The self -test result code is displayed visually on the
LANIC card (see Section 4), and can be programmatically read by the host via a channel register dedicated
to self-test result codes.
System Interrupt
The LANIC can request a host software interrupt via two pseudo-device interrupts. When the host issues
the OBII command to the LANIC, the data returned contains either a zero or a one in bit 1 S,
corresponding to the interrupting device number. Device number zero corresponds to the interrupt called
SINTRO, and device number one corresponds to the interrupt called SINTR
1. If
both interrupt requests,
SINTRO and SINTR 1, 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 SINTR 1 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 channeI(s) are requesting, and then an OBII to determine which device on the channel to
service. After determining which channel and device to service, the microcode issues a WIoe
command to clear SINTR, and dispatches the appropriate software interrupt routine.
SINTRO SELF-TEST INTERRUPT. The SINTRO interrupt request is activated by the ROM-based
self-test firmware when the self-test sequence completes or whenever an idle self -test failure is detected.
The host software reads the STR channel register to determine the type of error detected. A more
detailed description of the self -test is contained in Section 4.
SINTRI LANIC INTERRUPT. This interrupt is activated by either the ROM -based kernel firmware or
by the downloaded operational firmware to signal the host software that some event in the LANIC has
occurred. Host software reads the SR channel register to determine what type of event has occurred. The
types of events fall into two groups: those related to a command issued to LANIC by the host software,
and those resulting from internal LANIC operations.
Feb 85
3-6
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