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SMSC PCM-2074 User manual

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SMSC PCM-2074 USER MANUAL Revision 1.0 (03-31-06)
PCM-2074 EVB User Manual
PCM-2074 EVB User Manual
Revision 1.0 (03-31-06)
USER MANUAL SMSC PCM-2074
2
1 General Description
The PCM-2074 allows users to evaluate the CircLink
TM
protocol using a TMC2074 CircLink
TM
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
TM
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
TM
. 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
TM
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
TM
products
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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
D2
D1
CN1
CN2
D3
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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
ON
(=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)
1
2 P VDD (+5V)
1
3 I nCMIBYP
2
4 I nHUBON
2
5O TXEN
2
6P GND
7I RXIN
2
8P GND
9O TXD
2
10 P GND
11 I RXIN2
2
12 P GND
13 O TXEN2
2
14 I TXENPOL
2
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)
1
2 B GPIO7
3
3B GPIO6
3
4 B GPIO5
3
5B GPIO4
3
6 B GPIO3
3
7B GPIO2
3
8 B GPIO1
3
9B GPIO0
3
10 P GND
11 I nNSTCOUT
3
12 O nRST
2
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
47
54
85
.
6
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
47
47
2
.
6
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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
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
D
R
D
R
D
R
D
R
Offset
Transmission line: positive
Transmission line: negative
RS485 IC
Remove offset resistors on EVBs
located in the middle of the bus .
Termination resistor
Termination resistor
RS485 IC
RS485 IC
RS485 IC
CircLink Controller CircLink Controller
CircLink Controller
Offset
Offset
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
A
= I
B
= 0).
The voltage V
AB
between node A and B of the Receiver is:
Since V
TH,
the threshold voltage, ranges from -0.2V to +0.2V, and V
AB
> | V
TH
|, we can write an
equation for R
l
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
cc
and R
t
are at
their minimum values set a maximum value for R
l
. The equation for the worst-case can be written as
follows:
For the worst case conditions, we assume that V
CC
(min) = 4.75V, that R
t
(min) = 124 x 0.95 = 117.8Ω,
and that the threshold margin is 0.05V, therefore V
TH
(max)=0.25V. Putting these together, we get:,
Therefore, R
l
(nominal) = (1060.2 / 1.05) = 1009.7 Ω
To summarize, R
l
(nominal)= 1.0KΩ when Rt (nominal) = 124Ω, the threshold margin is .05V, and all
resistors have 5% tolerances. R
l
changes with the threshold margin. For a threshold margin of 0.01V,
R
l
= 1.2kΩ; for a margin of 0.1V, R
l
= 820Ω.
Since the actual I
A
and I
B
are not equal to 0, V
AB
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
AB
) during an
idle period using a digital voltmeter or oscilloscope.
Figure 9.4 Offset Resistor Value Calculation
D
DE
R
A
B
Vcc
GND
R
1
RS485
R
1
IA
The transmission line
side is in an open, or
floating state.
R
t
IB
Receiver portion
R
R
t
x (V
cc
)
(2 x R
l
)
+R
t
V
AB
=
R
t
x (V
cc
- V
TH
)
2 x V
TH
R
l
=
R
t
(min) x (V
cc
(min)- V
TH
(max))
2 x V
TH
(max)
R
l
(max)=
117.8 x (4.75 - 0.25)
2 x 0.25
R
l
(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
j
ack
connector
1
2
3
4
CN3
Modular
j
ack
connecto
r
1
2
3
4
L+
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
DI
DE
RE
A
B
RS-485 Transceiver
LTC1485
TXEN
TXD
RXIN
L+
GND
1K
1K
Vcc (+5V)
Drv
Rcv
GND
R
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.
Revision 1.0 (03-31-06) 16 SMSC SMSC PCM-2074
USER MANUAL
PCM-2074 EVB User Manual
Copyright © 2006 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient fo
r
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
t
specifications before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses
under any patent rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most
recently dated version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design
defects or errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC
products are not designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injur
y
or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the
customer. Copies of this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com.
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/