SMSC PCM-2074 User manual

Brand: SMSC

Model: PCM-2074

Type: User manual

SMSC PCM-2074 is a user-friendly evaluation board that allows users to evaluate the CircLinkTM protocol using a TMC2074 CircLinkTM controller. It comprises two boards linked by a 14-pin ribbon cable, acting as a CircLinkTM Host node. The PCM-2074 can communicate at a maximum rate of 5 Mbps. The Main Board features an on-board TMC2074 and a Type II PCMCIA interface. It has one socket for GPIO connectors. The RS485 Board comprises an RS485 transceiver and two RJ-11 modular jacks. The PCM-2074 is compatible with Windows 2000 and Windows XP and comes with a software driver and support library.

SMSC PCM-2074 USER MANUAL Revision 1.0 (03-31-06)

PCM-2074 EVB User Manual

Revision 1.0 (03-31-06)

USER MANUAL SMSC PCM-2074

1 General Description

The PCM-2074 allows users to evaluate the CircLink

protocol using a TMC2074 CircLink

controller configured for operation in peripheral mode. The PCM-2074 consists of two boards

connected by a 14-pin ribbon cable, which together act as a CircLink

Host node, and a software

driver. The maximum communication rate of the two-board-set is 5 Mbps.

The PCM-2074 Main Board contains the following:

 On-board TMC2074, configured to operate in peripheral mode

 Type II PCMCIA interface using ZiLOG Z1601720ASC

 One socket for GPIO connectors

Note: The PCMCIA connection does not support CardBus or ExpressCard

. It also does not

support the Suspend/Resume functions.

The PCM-2074 RS485 Board contains:

 An RS485 transceiver

 Two RJ-11 modular jacks

Note: The RJ-11 jacks are not configured to support the CircLink

Hub function.

The software driver supplied with the PCM-2074 supports Windows 2000 and Windows XP and comes

with a support library.

Note: Please download the latest version of the driver from SMSC’s website, along with the latest

version of this manual and other application notes relating to SMSC’s CircLink

products

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USER MANUAL Revision 1.0 (03-31-06)

2 Connectors and LEDs

The photograph below shows important features of the Main Board of the PCM-2074.

Figure 2.1 The PCM-2074 Main Board

CN1

CN3

CN4

CN1

CN2

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Table 2.1 Table of Connectors and LEDs for the PCM-2074 Main Board

DESIGNATOR SILKSCREEN DESCRIPTION

CN1 - 14-pin right-angle connector, attaches to CN1 of the RS485 Board via a

flat ribbon cable

CN2 - Through-holes for mounting a connector for the GPIO signals

D3 CS LED turns on when the host card is accessed via the PCMCIA interface

Table 2.2 Table of Connectors and LEDs for the PCM-2074 RS485 Board

DESIGNATOR SILKSCREEN DESCRIPTION

CN1 - 14-pin straight connector, attaches to CN1 of the Main Board via a flat

ribbon cable

CN3, CN4 - Two Modular RJ-11 jacks, electrically connected. Install 125 ohm

termination resistor across one of these connectors.

D1 PWR Turns on when power is supplied via CN1

D2 TXEN Turns on while transmitting.

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3 EVB Configuration (Jumper Settings)

The illustrations below shows the location of jumpers and switches on the two boards.

Note: CN2 and SW1 on the Main Board are not populated.

Figure 3.1 Location of Jumpers and Switches on the Main Board

Figure 3.2 Location of Jumpers and Switches on the RS485 Board

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3.1 Configuring the Main Board

Table 3.1 and Table 3.2 below how to configure the Main Board using SW2.

3.2 Configuring the RS485 Board

Table 3.3 and Table 3.4 below show how to configure the RS485 Board.

Note: The Hub function is not used on the PCM-2074; SW1-2 should always be set in the default

position.

Table 3.1 SW2 (Main Board) Configuration Settings

POS. NAME DESCRIPTION

(=0)

OFF

(=1) DEFAULT

8 MCKSEL1 Input clock frequency select, Bit 1 (MSB) See Ta ble 3. 2

below

10b

(20 Mhz)

7 MCKSEL0 Input clock frequency select, Bit 0 (LSB)

6 W16 Data Bus Width 8 16 8

5 WPRE1 Warning Timer 1, Bit 1 (MSB) Refer to TMC-

2074

Datasheet

11b

4 WPRE0 Warning Timer, Bit 0 (LSB)

3 NSTPRE2 NST Resolution, Bit 2 (MSB) Refer to TMC-

2074

Datasheet

000b

2 NSTPRE1 NST Resolution, Bit 1

1 NSTPRE0 NST Resolution, Bit 0 (LSB)

Table 3.2 Input Clock Configuration

MCKSEL1 MCKSEL0 CLOCK FREQ. MAX BAUD RATE

1 1 40 Mhz 5 Mbps

1 0 20 Mhz 2.5 Mbps

0 1 10 Mhz 1.25 Mbps

00 Reserved

Table 3.3 SW1 (RS485 Board) Configuration Settings

POS. NAME DESCRIPTION ON OFF DEFAULT

SW1-2 nHubON Enables Hub Mode Hub* No Hub No Hub

SW1-1 nCMIBYP Selects CMI or RZ mode RZ CMI CMI

Table 3.4 JP1, JP2 (RS485 Board) Configuration Settings

POS. NAME DESCRIPTION SHORT OPEN DEFAULT

JP1, JP2 (Offset

Resistor)

Connects or disconnects Offset

Resistors; both jumpers must be

set the same way

Connected Dis-

connected

Connected

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4 I/O Connectors

The Main Board has two connectors - CN1 and CN2 - to allow for input/output signals. CN1 comes

mounted with a 14-pin connector, which is used to attach the RS485 Board using a ribbon cable. CN2,

which has no connector attached, can be used for an optional GPIO (General Input/Output) connector.

Note: When using either connector, please adhere to the electrical limits specified in the TMC2074

datasheet.

Table 4.1 below shows the pin-out for the CN1 connector on the Main Board. It also shows the pin-out

for the CN1 connector on the RS485 Board, except that all locations noted as Inputs change to Outputs

and all locations noted as Outputs change to Inputs.

The pin-out for CN2 on the Main Board is shown in Ta ble 4. 2 below.

Table 4.1 Pin Assignments for CN1

Pin No. Attribute Name Pin No. Attribute Name

1 P VDD (+5V)

2 P VDD (+5V)

3 I nCMIBYP

4 I nHUBON

5O TXEN

6P GND

7I RXIN

8P GND

9O TXD

10 P GND

11 I RXIN2

12 P GND

13 O TXEN2

14 I TXENPOL

Legend: P = Power/Ground; O = Output, I = Input, N/C - No Connection

Notes:

1) Allowable current is 200mA or less;

2) All Input and Output signals are buffered by a TC74VHCT244 and have 10k-ohm pull-up resistors

connected.

Table 4.2 Pin Assignments for CN2

Pin No. Attribute Name Pin No. Attribute Name

1P VDD (+5V)

2 B GPIO7

3B GPIO6

4 B GPIO5

5B GPIO4

6 B GPIO3

7B GPIO2

8 B GPIO1

9B GPIO0

10 P GND

11 I nNSTCOUT

12 O nRST

Legend: P = Power/Ground; O = Output, I = Input, B - Bi-directional

Notes:

1) Allowable current is 100mA or less;

2) nRST is an active-low, reset output signal, and is buffered by a TC74VHCT08.

3) GPIO(7:0) and nNSTCOUT connect directly to the TMC2074, with no additional buffering.

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5 Reset

The Main Board provides a power-on reset signal which is driven by an MB3771 integrated circuit.

This circuit asserts the power-on reset signal when the Main Board is inserted into a PCMCIA slot, or

when the PC it is attached to is powered on. A second reset signal is provided by the Zilog

Z1601720ASC PCMCIA interface; this signal will reset the TMC2074 when asserted; it is also provided

to the CN2 connector.

6 Monitoring the CMI Decode Signal

When the Hub Function is disable, the CMI decoded signal (an RZ-coded signal) can be monitored on

the TP4 test point connection on the RS485 Board. Note that TP4 is not mounted.

7 Mechanical Specifications

Note: Each dimension represents a design value. Units are in mm.

Figure 7.1 Mechanical Specification for the Main Board

107

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Note: Each dimension represents a design value. Units are in mm.

8 Operating Conditions

9 Connecting Twisted Pair Cables to the RJ11 Connectors

The PCM-2074 provides two modular RJ11 jacks for connection to twisted pair cables, which need to

be supplied by the user. These cables should have a characteristic impedance of 125 ohms, in order

to match the impedance built into the board. Each end of the twisted pair cable should have a 125-

ohm termination resistor attached.

Recommended cables and terminators:

 Single wire type 125 ohm twisted pair cable (ARC-Cab/125T) from SMSC Japan

 125Ω terminator (ARC-Term/125T) from SMSC Japan

For recommendations on the maximum cable-length, minimum node-spacing, and maximum number

of nodes, refer to the TMC2074 data sheet.

Figure 7.2 Mechanical Specification for the RS485 Board

Table 8.1 Operating Conditions

PARAMETER SPECIFICATION

Supply Voltage +5V +/- 5%

Current Consumption 500 mA

Temperature Range 10 to 45C, no condensation

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9.1 Point-to-point Connection

Connect two evaluation boards as shown below. Attach a termination resistor to both ends.

9.2 Bus Connection

Connect three or more EVBs as shown below. Place termination resistors at each end of the network.

Note: In addition to the termination resistors, the Offset Resistors must be connected or disconnected

depending on the location. Refer to Section 9.3 for more details.

Figure 9.1 Point-to-Point Twisted Pair Connection

Figure 9.2 Bus Connection for 3 or more Nodes

Offset Resistors:

Connected

Evaluation Board 1

Offset Resistors:

Connected

Evaluation Board 1

Termination

Resistor

Termination

Resistor

Twisted Pair Cable

Offset Resistors:

Connected

Evaluation Board 1

Offset Resistors:

Disconnected

Evaluation Board 2

Offset Resistors:

Connected

Evaluation Board 3

Termination

Resistor

Termination

Resistor

Twisted Pair Cable

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9.3 Offset Resistors

The function of the offset resistors is to prevent the differential voltage on the twisted pair cable, which

is the voltage between the positive signal and the negative signal, from going to zero during idle

periods when nothing is driving the line. To maintain stable operation, the RS485 transceivers require

a differential voltage of generally at least 200mV.

The offset resistors, which operate as a pair, supply this differential. One Offset Resistor biases the

positive signal toward Vcc, while the other biases the negative signal toward ground. The configuration

of the offset resistors within a CircLink node depends on how that node is connected within a network.

The offset resistors should be installed on the end nodes of a network and should be removed or

disabled on the middle nodes of a network containing three or more nodes. This is shown in Figure 9.3

below. (In the PCM-2074, the offset resistors are configured using JP1 and JP2.).

Figure 9.3 Offset Resistors

Offset Resistor Configurations:

- Connect offset resistors on end-nodes

- Remove or disconnect offset resistors on middle nodes

CircLink Controller

Offset

Transmission line: positive

Transmission line: negative

RS485 IC

Remove offset resistors on EVBs

located in the middle of the bus .

Termination resistor

RS485 IC

CircLink Controller CircLink Controller

CircLink Controller

Offset

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9.3.1 Calculating the Value of the Offset Resistors

The discussion explains how the Offset Resistor values are calculated, and refers to Figure 9.4.

In order to simplify the following discussion, assume the sink and source currents are zero (I

= I

= 0).

The voltage V

between node A and B of the Receiver is:

Since V

TH,

the threshold voltage, ranges from -0.2V to +0.2V, and V

> | V

|, we can write an

equation for R

as follows:

However, we must guarantee that under worst-case conditions, the differential voltage exceeds the

required threshold voltage with some margin. These conditions, which occur when V

and R

are at

their minimum values set a maximum value for R

. The equation for the worst-case can be written as

follows:

For the worst case conditions, we assume that V

(min) = 4.75V, that R

(min) = 124 x 0.95 = 117.8Ω,

and that the threshold margin is 0.05V, therefore V

(max)=0.25V. Putting these together, we get:,

Therefore, R

(nominal) = (1060.2 / 1.05) = 1009.7 Ω

To summarize, R

(nominal)= 1.0KΩ when Rt (nominal) = 124Ω, the threshold margin is .05V, and all

resistors have 5% tolerances. R

changes with the threshold margin. For a threshold margin of 0.01V,

= 1.2kΩ; for a margin of 0.1V, R

= 820Ω.

Since the actual I

and I

are not equal to 0, V

may be less than 0.2V. Further tuning of the resistor

values may be required. To do this, measure the voltage between the receiver inputs (V

) during an

idle period using a digital voltmeter or oscilloscope.

Figure 9.4 Offset Resistor Value Calculation

Vcc

GND

RS485

The transmission line

side is in an open, or

floating state.

Receiver portion

x (V

)

(2 x R

)

x (V

- V

)

2 x V

(min) x (V

(min)- V

(max))

2 x V

(max)

(max)=

117.8 x (4.75 - 0.25)

2 x 0.25

(max)=

=1060.2Ω

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9.4 RJ11 Pin Out

As shown in the figure above, only the two middle pins are used regardless of the number of pins

available. The pin just to the left of the middle is always positive (L+) and the pin just to the right of

the middle is always negative (L-).

9.5 Routing to Modular Jack Connectors

Figure 9.5 Pin Out of an RJ-11 Modular Jack (Front View)

Figure 9.6 Routing to Modular Jack Connectors

4 Pin Type

6 Pin Type

Polarity

Pin Number

CN4

Modular

ack

connector

CN3

Modular

ack

connecto

L+

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10 Transceiver Implementation

The use of a non-isolated RS485 transceiver (the method used by the PCM-2074) is shown in the

figure below.:

For other transceiver implementations, refer to the CircLink Application Notes on the SMSC website.

11 Using the PCM-2074 with a Desktop PC

To use the PCM-2074 evaluation board in the PCI slot of a desktop PC, please use a general-purpose

conversion adaptor between the PCI slot and the PCM-2074 PCMCIA connector, such as the P111

from Elan Digital Systems (website: www.elandigitalsystems.com). Note that there is no guarantee of

operation or technical support provided by SMSC for this application.

Figure 10.1 Non-Isolated RS485 Transceiver

RS-485 Transceiver

LTC1485

TXEN

TXD

RXIN

L+

GND

Vcc (+5V)

Drv

Rcv

GND

L-

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12 Care and Usage Information

12.1 Precautions for Handling and Storage

1. For proper operation, environmental and power supply limitation requirements must be adhered to.

2. Do not expose the PCM-2074 to chemicals or to liquids, such as water or oil, or to moisture or

vapor during handling or storage. Such exposure may result in electrical shock, short circuits,

damage to the PCM-2074, or fire.

3. Use and store the PCM-2074 on a stable, level surface, and avoid mechanical vibration or shock.

4. Do not subject the PCM-2074 to direct sunlight or excessive heat. Exposing the board to excessive

heat during use may damage it. Exposing the board to direct sunlight may cause damage or

warpage.

5. Do not use or store boards in dusty places.

6. Avoid using the PCM-2074 near TVs, radio receivers, cordless phones or similar devises. The

PCM-2074 may cause Electro-Magnetic Interference with these devices.

7. Do not use or store the PCM-2074 near equipment that generates strong electro-magnetic fields.

Exposure to excessive Electro-magnetic fields may damage the board.

8. Do not put heavy loads on top of the PCM-2074 as this may damage it.

9. Avoid exposing the PCM-2074 to exogenous material such as metal particles. These may cause

short circuits and fire.

12.2 PC Installation Procedure

1. Confirm that all jumpers and dip switches on both the Main Board and the RS485 Board are set

correctly.

2. Attach the RS485 Board to the Main Board using the ribbon cable, then insert the Main Board into

a PCMCIA slot, avoiding excessive force and aligning the card and slot correctly.

3. Avoid inserting or removing the RS485 Board during the power-on state.

4. Avoid excess stress on the ribbon cable connecting the Main Board to the RS485 Board.

5. Be sure not to exceed current consumption limits when providing power via CN1 or CN2.

6. Confirm correct operation of the evaluation board.

12.3 De-Installation Procedure

1. Power off the system before removing boards or connectors to prevent damage.

2. Avoid excessive force when removing cables, boards, sockets or devices to avoid damaging them.

12.4 Miscellaneous Warnings

Attaching the PCM-2074 to a non-SMSC authorized fixture or PC may cause the following failures.

 The PC may not function correctly.

 The board does not work or exhibits intermittent failures.

 The board causes damage to either the PC or other peripherals.

If there is a possibility that adjacent boards may contact each other, insert an insulator between them

to avoid electric contact which may cause a defect in the board, system or peripherals, electric shock,

or fire.

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USER MANUAL

PCM-2074 EVB User Manual

Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient fo

construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies.

SMSC reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the lates

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