Interrupt level, Wait state jumper – Measurement Computing CIO-DAS801 User Manual
Page 12

CIO-DAS801 User's Guide
Installing the CIO-DAS801
12
Interrupt level
In order to take advantage of high speed transfers, you must provide the board with an interrupt that is not used
by other devices in your computer. Use the jumper block labeled IR (above the PC bus interface) to select an
interrupt level between 2 and 7, or to disable interrupts (X). By default, the board is shipped with no interrupt
level set (the jumper is in the 'X' position). Figure 5 shows the interrupt level set for IRQ 5.
IR
2 3 4 5 6 7 X
Figure 5. Interrupt level select jumper
Set the interrupt level jumper if your software requires it. The Universal Library and other programs which take
advantage of the REP-INSW high speed transfer capability of the board require an interrupt. If you set the
interrupt jumper, check your PC's current configuration for interrupt conflicts. Refer to the table below for
typical IRQ assignments.
IRQ assignments
Name
Description
Name
Description
NMI
Parity
IRQ8
Real Time Clock (AT)
IRQ0
Timer
IRQ9
Re-Directed to IRQ2 (AT)
IRQ1
Keyboard
IRQ10
Unassigned
IRQ2
Reserved (XT)
INT 8-15 (AT)
IRQ11
Unassigned
IRQ3
COM OR SDLC
IRQ12
Unassigned
IRQ4
COM OR SDLC
IRQ13
80287 Numeric CO-P
IRQ5
Hard Disk (XT)
LPT (AT)
IRQ14
Hard Disk
IRQ6
Floppy Disk
IRQ15
Unassigned
IRQ7
LPT
Note: IRQ8-15 are AT only
Wait state jumper
Enable the wait state jumper if you have a computer with an I/O bus transfer rate which is too fast for the CIO-
DAS801, or if the board fails sporadically in random ways.
To enable the wait state, set the jumper labeled
WS1
to the ON position. Enabling the wait state causes the
personal computer's bus transfer rate to slow down whenever the CIO-DAS801 is written to or read from. This
jumper is shown in Figure 6 configured for OFF (wait state is disabled).
ON
OFF
WS1
Figure 6. Wait State jumper
The wait state generator on the CIO-DAS801 is only active when the CIO-DAS801 is being accessed. Your PC
will not be slowed down in general by using the wait state.