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Div1 div4 – Impulse 3420 User Manual

Page 9

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Card

Setup

Sealevel Systems COMM+8 Page

6

Set all jumpers to “S” if you are using more than one COMM+8 in a bus
or you wish to completely remove the pull-down resistor for hardware
compatibility. Setting the COMM+8 in this configuration when it is not
accompanied by a pull-down resistor will prevent the ports from
triggering an interrupt
.

1
2

3
4

5
6

7
8

N S M N S M

E9

E10

Figure 6 - Header E9 and E10, Sharing IRQs with another adapter

Clock Modes

The COMM+8 employs a unique clocking option that allows the user to
select from divide by 4 or divide by 1 clocking modes. This mode is
selected at E12.

To select the Baud rates commonly associated with COM: ports (i.e. 2400,
4800, 9600, 19.2, … 115.2K Bps) place the jumper in the divide by 4
mode (silk-screen DIV4).

DIV1

DIV4

Figure 7 - Clocking Mode ‘Divide By 4’