Vector Graphic Bitstreamer II, Руководство пользователя

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To deternine the source of t..'1e interrupt within a 3itstreamer II board,
software must poll potential interrupt sources on the board. If none of the
825l's are active, then the clock must be the source.
After
dIe
CPU responds to an interrupt by transf9rring control to the
interrupt service routine, the source of the interrupt must be cleared
before re-enabling interrupts with ~he EI instruction. To clear one of the
8251 interrupt sources, software must input from the I/O address of that
8251. The inputted byte does not have to be used by the software for any
purpose. To clear the real time clock interrupt latch, software must input
from Parallel Channel 3. If a spurious interrupt is received, for which
software cannot determine a source, it is a good idea to clear all potential
interrupt &~urces.
The eight 5-100 VI lines are available on the board for communicating
interrupts to a'1other ooard for prioritization or other kinds of ?rocess ing
before
reaching the CPU. At this time, no Vector Graphic board is designed
to make use of such signals. If you do make use of them on another board,
you would not tie any of the pads in area A to pad A-8 (PINT). Instead,
jumper tl1edesired pads in area A to the pads in area K. Each pad in area K
corresponds to one of t..'1e VI lines VI0 to VI7, as follows:
VI Line Area K pad
0
1
1
2
2
3
3 4
4
5
5 6
6
7
7 8
VI Lines Available in Area K
Table 11