SMSC DS – TMC2005

Page 21

Rev. 10/24/2000

PORT GROUP

The five ports can be divided into three groups (group A: two ports, group B: two ports, extension port: one port) and

each group can select TX/RX polar, noise cut mode, and big jitter mode respectively. Select pins for each group are

as follows:

FUNCTION

GROUP A

GROUP B

EXTENSION

RECEIVE

RXINA0, 1

RXINB0, 1

EXTRX

TRANSMIT

TXENA0, 1

TXENB0, 1

EXTTX

RX POLARITY

SA

SB

SE

TX POLARITY

LA

LB

LE

TX CONTROL

MA

MB

ME

NOISE CUT

nMBA

nMBB

nMBE

BIG JITTER

nBJA

nBJB

nBJE

EXTENSION

nEXTOD

Various Setup

Example For Operation Mode Setup To Each Port

SA, SB, SE

LA, LB, LE

MA, MB, ME

RX POLAR

TX POLAR

TRANSCEIVER

1

0

1

Active Low

Active Low

HYC2485S/HYC2488S

0

1

0

Active High

Active High

Optical Transceiver

0

0

1

Active High

Active Low

HYC9088/HYC9068

1

1

1

Active Low

Active High

RS485 Transceiver

Note for Unused port

Unused ports can be left open because RX port (RX input), RX polar (S input), TX polar (L input), TX control (M

input) pins have internal pull-up resistors. Because of internal pull-up resistors, select pins for noise cut (nMB

input), big jitter (nBJ input) can be left open when used for setting “OFF”.

Example for Power-On Reset Circuit

FIGURE 9 - POWER-ON RESET

+5V

TMC2005

39

nRST

TMC2005

39

nRST

Rp

10K

Cp

4.7uF

Ct

0.1uF

3

2

MB3771/NJM2103

1

2

3

4

5

6

7

8

1

2T

2T

2T

2T

2T

2T

2T

POWER-ON RESET CIRCUIT (C, R)

POWER-ON RESET CIRCUIT (POR IC)

+5V