2. Getting Started
17
INFOSET 300 9 I/O UTP
To set the ZT 8995-D2 board to a base I/O address of 280h, using interrupt level IR5,
and thin Ethernet (
connector J4
) the command line is:
INFOSET 280 5 I/O THIN
If you plan to use the AUI connector (
J3
) the command variable "THICK" replaces
"THIN" in the command line. See also the jumper description for
W10
.
Interrupt Scheme
The ZT 8995 supports the selection of one of four backplane interrupts and three
frontplane interrupts via software control.
The on-board DP83905 (AT/LANTIC controller chip) must be programmed to use the
encoded mode interrupt scheme. To do this, set the INTMODE bit in
Configuration
Register C
HIGH (logic 1). The values in bits 3-5 of
Configuration Register A
select the
desired interrupt.
Note:
The INFOSET or AUTOSET8 programs set the proper bits in this register for you
when you select your interrupt level.
The ZT 8995 uses an encoded interrupt scheme. A decoder maps the AT/LANTIC's
interrupt to one of the STD 32 interrupts, as shown in the "
Interrupt Selection
" table.
This interrupt scheme is Novell NE2000
plus compatible. The INT3 pin from the
AT/LANTIC strobes true when an interrupt is generated by the AT/LANTIC' s internal
circuitry. The selected interrupt is output from the decoder (strobed LOW) for the
duration of the INT3 strobe.
This means that the interrupt outputs are intended for use in an edge-triggered interrupt
environment. They do not function correctly in a machine with level-triggered interrupts;
interrupts may be missed.
By definition, the STD 32 bus uses edge-triggered interrupts; however, interrupts can be
system selected to be either edge or level triggered.
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