User`s guide

5.1 BOARD CONTROL REGISTERS
5.1.1 INTERRUPT STATUS/CONTROL
BADR1 + 4C (hex)
READ/WRITE
INTEINT-
POL
INTxxxPCIINTxx
0123456731:8
This register is 32-bits in length. Please note that the remainder of the register's bits
have specific control functions. If you write the Interrupt Status register, please be
sure to read the current status, change only the desired bits and then write the new
status word.
INTE is the Interrupt Enable:
0 = disabled,
1 = enabled (default).
INTPOL is the Interrupt Polarity:
0 = active low (default),
1 = active high.
INT is the Interrupt Status:
0 = interrupt is not active,
1 = interrupt is active.
PCIINT is the PCI Interrupt Enable:
0 = disabled,
1 = enabled (default).
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5.1.2 USER I/O STATUS/CONTROL (PCI-DIO24H/CTR3 only)
BADR1 + 50 (hex)
READ/WRITE
01OUT0xxxxxx
0123456731:8
Though the onboard crystal oscillator output is not brought to the I/O connector, it
may be connected to the clock input of counter 0 by installing a jumper on the board
(between OSC and CLK0 on P2). The on board oscillator may be set to 10 MHz or
1 MHz. The OUT0 bit selects which frequency is brought to the jumper pin.
OUT0 = 0, input = 10Mhz
OUT0 = 1, input = 1Mhz.
Bit 0 and one should remain 0 and 1 respectively.
This register is 32-bits in length. Please note that the remainder of the register's bits
have specific control functions. If you write the User I/O Status/Control register,
please be sure to read the current status, change only the desired bits and then write
the new status word.
5.1 82C55 CONTROL & DATA REGISTERS
Each PCI-DIO24 is composed of an 82C55 parallel I/O chip (or a TTL implementa-
tion of 8255 mode 0). Each board uses 3 data and one control register and occupies 4
consecutive I/O locations. The PCI-DIO24H/CTR3 uses 4 additional I/O registers to
read and write to the 82C54.
The PCI-DIO24 series boards are easy to program with direct I/O register reads and
writes. A tutorial describing how to go about register I/O is beyond the scope of this
manual. However, it will be covered in most Introduction To Programming books,
available from a bookstore.
As alternatives to register level programming, the PCI-DIO24 series of boards is fully
supported by optional Universal Library software as well as most high level data
acquisition and control application packages (e.g. HP Vee or Labtech Notebook).
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