rev. 7/7/03

SP508 Evaluation Board Manual

© Copyright 2003 Sipex Corporation

8

Driver Enable Dip Switch

(off = logic 1, on = logic 0)

The individual switches in the off position

leaves the individual enable pin floating (in-

ternally pulled up or down?) which enables

the driver. The switch in the on position ties

the high true enable pins to ground and the

disabling the individual drivers.

Receiver Enable Dip Switch

(off = logic 0, on = logic 1)

The individual switches in the off position

leaves the individual enable pins floating

(internally pulled down or up?) which en-

ables the receiver. The switch in the on

even the high true TMEN. The TMEN pin is

always high no matter what position the dip

switch is in. To disable the TM receiver the

DIP SWITCH USERS GUIDE

SP508 DIP SWITCH TRUTH TABLE

Switch

ON LOGIC

OFF LOGIC

D0

0

1

DECODER

D1

0

1

DECODER

D2

0

1

DECODER

LOOPBACK

0

1

Logic 0 indicates SP508 is in LOOPBACK mode

TERM_OFF

1

0

Logic 1 internal termination is disables

D_LATCH

1

0

Logic 0 Latch is disabled

SDEN

0

1

Logic 1 TXD driver is enabled

TTEN

0

1

Logic 1 TXCE driver is enabled

STEN

0

1

Logic 1 ST driver is enabled

RSEN

0

1

Logic 1 RTS driver is enabled

TREN

0

1

Logic 1 DTR driver is enabled

RRCEN

0

1

Logic 1 DCD_DCE driver is enabled

RLEN

0

1

Logic 1 SD driver is enabled

LLEN

1

0

Logic 0 LL driver is enabled

RDEN

1

0

Logic 0 RXD receiver is enabled

RTEN

1

0

Logic 0 RXT receiver is enabled

TXCEN

1

0

Logic 0 TXC receiver is enabled

CSEN

1

0

Logic 0 CTS receiver is enabled

DMEN

1

0

Logic 0 DSR receiver is enabled

RRTEN

1

0

Logic 0 DCD_DTE receiver is enabled

ICEN

1

0

Logic 0 RI receiver is enabled

TMEN

0

1

Logic 1 TM receiver is enabled

DIP switch

must be off and the external pin

labeled TMEN is to be jumped to ground.

Decoder DIP Switch

(off = logic 1, on = logic 0)

The decoder DIP switch is configured such

that the switch in the off position allows the

decoder pins to float as well as the

notLOOPBACK pin. (all of these pins are

assumed to have internal pull-ups.) The dip

switch in the on position grounds each of

these pins.

DCE_DTE Selectable Switches

• Switch bank 1 ON = ST driver outputs tied

to TxC receiver inputs and also tied to D-

SUB connector for remote evaluation.

• Switch bank 2 ON = RRC driver outputs

tied to RRT receiver inputs and also tied to

D-SUB connector for remote evaluation.