Acer 486 Specifications download pdf (Page 17)

Chapter 1 Hardware Configuration 9

How to set jumpers

You configure your card to match the needs of your application by

setting jumpers. A jumper is the simplest kind of electric switch. It

consists of two metal pins and a small metal clip (often protected by a

plastic cover) that slides over the pins to connect them. To “close” a

jumper you connect the pins with the clip. To “open” a jumper you

remove the clip. Sometimes a jumper will have three pins, labeled 1, 2

and 3. In this case you would connect either pins 1 and 2 or 2 and 3.

If you have any doubts about the best hardware configuration for your

application, contact your local distributor or sales representative

before you make any changes.

Display type (JP15)

This jumper sets the display adapter type attached to your card. If you

are using a monochrome LCD or EL screen which uses a CGA, EGA,

VGA or other color display adapter, set JP15 to color.

JP15 Setting

Open Monochrome

Closed (default) Color

Watchdog timer  system reset/IRQ15 (JP8)

When the watchdog timer activates (CPU processing has come to a

halt), it can reset the system or generate an interrupt on IRQ15. Set

jumper JP8 as shown in the following table:

JP8 Setting

1-2 System Reset

3-4 IRQ15

Bus clock selection (JP4)

JP4 Selection

1-2 Bus clk = CPU clk * 2/8

2-3 Bus clk = CPU clk * 2/6

1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 38 39

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Acer 486 Specifications Page 17