Interrupt level – Measurement Computing CIO-DIO24/CTR3 User Manual
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CIO-DIO24/CTR3 User's Guide
Installing the CIO-DIO24/CTR3
PC I/O Address Summary
Hex Range
Function
Hex Range
Function
000-00F
8237 DMA #1
2C0-2CF
EGA
020-021
8259 PIC #1
2D0-2DF
EGA
040-043
8253 TIMER
2E0-2E7
GPIB (AT)
060-063
8255 PPI (XT)
2E8-2EF
SERIAL PORT
060-064
8742 CONTROLLER (AT)
2F8-2FF
SERIAL PORT
070-071
CMOS RAM & NMI MASK (AT)
300-30F
PROTOTYPE CARD
080-08F
DMA PAGE REGISTERS
310-31F
PROTOTYPE CARD
0A0-0A1
8259 PIC #2 (AT)
320-32F
HARD DISK (XT)
0A0-0AF
NMI MASK (XT)
378-37F
PARALLEL PRINTER
0C0-0DF
8237 #2 (AT)
380-38F
SDLC
0F0-0FF
80287 NUMERIC CO-P (AT)
3A0-3AF
SDLC
1F0-1FF
HARD DISK (AT)
3B0-3BB
MDA
200-20F
GAME CONTROL
3BC-3BF
PARALLEL PRINTER
210-21F
EXPANSION UNIT (XT)
3C0-3CF
EGA
238-23B
BUS MOUSE
3D0-3DF
CGA
23C-23F
ALT BUS MOUSE
3E8-3EF
SERIAL PORT
270-27F
PARALLEL PRINTER
3F0-3F7
FLOPPY DISK
2B0-2BF
EGA
3F8-3FF
SERIAL PORT
You can set the base address switch to any address in the range of 000-3FC. If you are not using IBM
prototyping cards or another board which occupies these addresses, the CIO-DIO24/CTR3 board's default
address of 300h is free to use.
Addresses not specifically listed, such as 390-39Fh, are not reserved and may be available. Check your
computer for other boards which may use I/O addresses.
Interrupt level
The trigger logic on the CIO-DIO24/CTR3 is quite simple. Pin 1 (
IR Input
) of the board's 37-pin connector is
an input jumper which maps the interrupt directly onto the PC bus. The signal to the bus is buffered. The buffer
is enabled by a LOW level on Pin 2,
IR Enable
.
Interrupts are hardware-initiated software routines. Most hardware interrupts are assigned by the computer and
are reserved for internal system use. Refer to the following table for some typical interrupt assignments on a
computer.
The CIO-DIO24/CTR3 is shipped with the jumper in the "
X
" position, which means that no interrupt level is set
). Leave the jumper in the default "X" position for now. If your software employs interrupt service
routines, it will direct you to select an IRQ level. Use the jumper block labeled
IR
above the PC bus interface
(gold pins) if you want to set the interrupt.
Figure 3. Interrupt level select jumper (no interrupt level set)
IR
2 3 4 5 6 7 X
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