DIO48S/AT-P Manual
Page 1-2
Manual 00650-526-1
Also, bit C3 at each 24-bit port can be used as an external interrupt to the computer if jumpers are
installed. When bit C3 goes high (edge triggering), an interrupt is requested. Interrupts from the
ports are OR'ed together and OR'ed with the change-of-state interrupt. Interrupts are directed to
levels #2 through #7, #10 through #12, #14 and #15 by jumper installation.
The DIO48S/AT-P card was designed for industrial applications and can be installed in 16-bit
ISA bus slots of IBM PC/XT/AT or compatible computers. Each I/O line is buffered and capable
of sourcing 15 mA or sinking 24mA (64 mA on request). The card contains two Programmable
Peripheral Interface chips type 8255-5 (PPI) to provide computer interface to 48 I/O lines. Three
8-bit ports A, B, and C. Each 8-bit port can be software configured to function as either inputs or
output latches. Port C can also be configured as four inputs and four output latches. Pull-ups on
the card assure that there are no erroneous outputs at power up until the card is initialized by
system software.
Tristate I/O line buffers (74LS245) are configured automatically by hardware logic for input or
output use according to direction assignment from a control register in the PPI. Further, if a
jumper is properly placed on the card, the tristate buffers are enabled/disabled under program
control. (See the Option Selection section to follow.)
I/O wiring connections are via 50-pin headers on the board. Two flat I/O cables connect
DIO48S/AT-P to termination. Also, this provides compatibility with OPTO-22, Gordos, Potter &
Brumfield, and all module mounting racks. Every second conductor of the flat cables is grounded
to minimize the effect of crosstalk between signals. If needed for external circuits, +5 VDC power
is available on each I/O connector pin 49. If you use this power, we recommend that you include a
1A fast-blow fuse in your circuits in order to avoid possible damage to the host computer or cable
in the event of a malfunction in those external circuits.
The DIO48S/AT-P occupies sixteen bytes of I/O address space. The base address is selectable via
a DIP switch anywhere within the range of 000-3F0 hex. An illustrated setup program is provided
with the DIO48S/AT-P card. Interactive displays show locations and proper settings of DIP
switches and jumpers to set up board address, interrupt levels, and interrupt enable. Also, sample
programs in Turbo-C and Turbo-Pascal are presented in the Software section of this manual.
Summary of Contents for DIO48S/AT-P Series
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