Wait state jumper – Measurement Computing CIO-DAC02 User Manual
Page 10

CIO-DAC02 User's Guide
Installing the CIO-DAC02
10
In the default configuration shown in Figure 2, 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.
PC I/O addresses
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-3BB
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
The CIO-DAC02 Base switch can be set for an address in the range of 000-3E0, so it should not be hard to find
a free address area for your CIO-DAC02. If you are not using IBM prototyping cards, or some other board
which occupies these addresses, then 300-31F HEX are free to use. Addresses not specifically listed, such as
390-39F, are free.
Wait state jumper
The CIO-DAC02 board has a wait state jumper which you can set to enable an on-board wait state generator. A
wait state is an extra delay injected into the processor's clock via the bus. This delay slows down the processor
when the processor addresses the CIO-DAC02 board so that signals from slow devices (chips) will be valid.
This jumper is shown in Figure 3 configured for OFF (wait state is disabled).
O
N
O
F
F
Figure 3. Wait State jumper
The wait state generator on the CIO-DAC02 is only active when the CIO-DAC02 is being accessed. Your PC
will not be slowed down in general by using the wait state.