Base Address - Measurement Computing CIO-DIO24H User Manual

CIO-DIO24H User's Guide
Switch/jumper
Base address DIP switches
Interrupt level jumper
Wait State jumper
Review the following information to change the default configuration of a switch or jumper.

Base address

The easiest way to set the base address is to let InstaCal show you the correct settings. However, if you are
already familiar with setting ISA base addresses, you may use the base address switch description below to
guide your base address selection.
Each I/O board uses one or more I/O address locations within your computer's I/O address space. To avoid
interference with other installed boards, each board must use unique addresses. The base address is the board's
starting location that software writes to when communicating with the CIO-DIO24H. A set of DIP switches is
used to set the base address. By placing the switch down, the CIO-DIO24H address decode logic is instructed
to respond to that address bit. A complete address is constructed by calculating the HEX or decimal number
which corresponds to all the address bits the board has been instructed to respond to.
The board is shipped with the base address set to 300 hex (see
system that uses address 300 hex (768 decimal), leave the switches as they were set at the factory.
In the default configuration, addresses 9 and 8 are down, and all others are up. Address 9 = 200 hex
(512 decimal), and address 8 = 100 hex (256 decimal). When added together they equal 300 hex (768 decimal).
Disregard the numbers printed on the switch
When setting the base address, refer to the numbers printed in white on the printed circuit board.
Certain addresses are used by the computer. Other addresses are free, and may be used by the CIO-DIO24H.
Refer to the following table for a list of I/O addresses.
Hex Range Function
000-00F 8237 DMA #1
020-021 8259 PIC #1
040-043 8253 TIMER
060-063 8255 PPI (XT)
060-064 8742 CONTROLLER (AT)
070-071 CMOS RAM & NMI MASK (AT)
080-08F DMA PAGE REGISTERS
Factory-configured default settings
Description
Sets the base address
Sets the interrupt level
Enables/disables the on-board wait-state
generator.
9 8 7 6 5 4
Figure 2. Base address switch
PC I/O Address Summary
10
Default setting
300h (768 decimal)
"X" position (no interrupt level set)
Off (disabled)
Figure 2 . Unless there is already a board in your
)
SW HEX
A9 200
3 2
A8 100
A7 80
A6 40
A5 20
A4 10
A3 08
A2 04
Hex Range Function
2C0-2CF EGA
2D0-2DF EGA
2E0-2E7 GPIB (AT)
2E8-2EF SERIAL PORT
2F8-2FF SERIAL PORT
300-30F PROTOTYPE CARD
310-31F PROTOTYPE CARD
Installing the CIO-DIO24H