ICS DIO48S/AT-P Series, Product Manual

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Page 3-1
Manual 00650-526-1
Chapter 3: Option Selection
Refer to the setup programs provided with the card. Also, refer to the Block Diagram on Page 1-4
and the Option Selection Map on the following page when reading this section of the manual.
External Interrupts are accepted on the I/O connector pin 9 (bit C3). The Interrupt signal is
positive true. External Interrupts are enabled if the IEN jumper is installed. Interrupts are directed
to levels #2 through #7, #10 through #12, #14 and #15 by jumpers installed at locations labeled
IRQ2 through IRQ7, IRQ10 through IRQ12, IRQ14 and IRQ15 respectively.
A means of enabling or disabling the 74LS245 input/output buffers under program control is
provided at the jumper position labeled TST/BEN. When the jumper is in the BEN (Buffer
Enable) position, the I/O buffers are always enabled. When the jumper is in the TST (Tristate)
position, enabled/disabled state is controlled by a control register. (See the programming section of
this manual for a description.)
An LED, CR1, is provided at the top-center of the card to assist you in program development.
Each time an interrupt is generated, the LED will illuminate and remain on until the interrupt is
reset. If there is an immediate reset of the interrupt, it is likely that the LED will not remain on
long enough to be observed.
Note
A jumper must be installed in either the TST or the BEN position for the card to function.
There is a wire jumper installed on the card at a position labeled WAIT. The associated circuitry
asserts a WAIT signal to the CPU in order to provide a longer write cycle. In this way, there is
assurance that the 8255 PPI. will have adequate time to accept inputs from the CPU in fast AT
computers. If this extra wait state will cause a problem in your application and if you deem it
non-essential, then this wire jumper may be clipped.
The foregoing are the only manual setups necessary to use the DIO48S/AT-P. Input/Output
selection and the change-of-state Interrupt Enable is done via software by writing to a control
register in each PPI as described in the Programming section of this manual.