Linear Technology DC1880A Quick setup guide

1
dc1880af
DEMO MANUAL DC1880A
Description
LTC2874
Quad IO-Link Master
Hot Swap Controller and PHY
Demonstration circuit 1880A showcases the LTC
®
2874, a
quad Hot Swap™ controller and PHY suitable for IO-Link
®
master and other applications. DC1880A operates from
an external supply VDD and utilizes the DC590 USB serial
controller board to communicate with the LTC2874 using
SPI protocol.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot
Swap, QuikEval and Linduino are trademarks of Linear Technology Corporation. IO-Link is
a registered trademark of PROFIBUS User Organization (PNO). All other trademarks are the
property of their respective owners.
performance summary
Design files for this circuit board are available at
http://www.linear.com/demo/DC1880A
Specifications are at TA= 25°C, VDD = 24V, and VL= 3.3V.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VDD Input Supply Range 24VMODE = 0
24VMODE = 1 8 20 30 30 V V
ΔVACL L+ Analog Current Limit Voltage ΔVACL = VSENSE+– VSENSE–
VL+ = 0V, FLDBK_MODE = 1
VL+ = VDD – 1V
Start-Up, 2XPTC Enabled, VL+ > 18V
9.2
42
16.7
50
100
24.2
58
mV
mV
mV
ΔVGATE External N-Channel Gate Drive
(VGATE – VL+)IGATE = –1µA
VDD = 17V to 30V
VDD = 8V
10
4.5
13 15
15
V
V
V
VRQH,
VRQL
CQ Residual Voltage Output High, ICQ = –100mA
Output Low, ICQ = 100mA 1.2
1.1 1.6 1.5 V V
IQPKH,
IQPKL
Wake-Up Request (WURQ) Current ±500 ±700 mA
IQH, IQL CQ Current Limit ±110 ±160 ±230 mA
fDTR Maximum Data Transfer Rate fDTR = 4nF
SLEW = 0
SLEW = 1
38.4
230.4
kb/s
kb/s
tWU WURQ Pulse Duration 75 80 85 µs
SCK Frequency 50% Duty Cycle 20 MHz

2
dc1880af
DEMO MANUAL DC1880A
Quick start proceDure
Figure 1. Proper Setup

3
dc1880af
DEMO MANUAL DC1880A
Quick start proceDure
DC1880A is a 6-layer demonstration board. An LDO is
included to optionally derive the VLlogic supply from
the VDD input supply. An LED lights up when the IRQ pin
signals interrupt requests.
1. Install, or update as needed, Linear Technology's
QuikEval™ evaluation software on the PC. See Using
the LTC2874 Software section for more information.
2. Connect the DC590 board to the PC with a standard
USB A/B cable.
3. Connect the DC1880A board to the DC590 board using
the14-conductorribboncablesuppliedwiththeDC590
board.
4. ChoosethesourcefortheVLlogicsupply—theDC590,
the LDO on the DC1880A, or either if both are set to
the same voltage:
a. SettheDC1880ALDOjumpers(JP11andJP12)and
DC590 VCCIO jumper (JP6) to one of the combina-
tions listed in Table 1. Default jumper positions set
both boards to 5V.
b. When using a Linduino™ One instead of a DC590
board, set the DC1880A LDO to 5V(JP11 = 5.0V)
or disable it (JP12 = OPEN).
5. Before connecting the input power supply to the
DC1880A board, verify the voltage is below 40V
(normally between 8V and 30V) and that the supply
is turned off.
6. Connect the power supply between VDD and GND on
the DC1880A board as shown in Figure 1.
7. Connect line interface cables (up to 20m long) to either
the screw-terminal blocks (J1-J4) or the IO-Link con-
nectors (J5-J8).
8. Turn on the 24V power supply and verify that the IRQ
LED on the DC1880A board is lit. (The LTC2874 is
signalling that one or more of its supplies had been
low.)
9. Launch the GUI software. Refer to the Using the
LTC2874 Software section for more information on
how to control the LTC2874 using the GUI.
10.Clear the IRQ condition by clearing any Supply Event
bits that are set. On the Events tab, simply click on any
lamps that are lit.
11.Refer to the Additional Information section and the
data sheet for operating details.

4
dc1880af
DEMO MANUAL DC1880A
aDDitional information
VL Logic Supply
Table 1 lists several ways to supply power to the VL pin.
Methods 1a/b/c are recommended for most purposes.
Table 1. Recommended Options for Powering the VL Supply
METHOD
DC590
JP6
DC1880A
JP12
DC1880A
JP11
SOURCE FOR
VL POWER
1a
1b
1c
5V*
3.3V
OPEN (2.7V)
ON*
ON*
ON*
5V*
3.3V
OPEN (2.9V)
LDO or DC590
LDO or DC590
LDO or DC590
2 EXT ON* X** LDO
3 EXT OPEN X** DC1880A VL TURRET
4 5V* or 3.3V OPEN X** DC590
* (Default)
** Including OPEN (2.9V)
L+ Power Supply Outputs
Enable the L+ power supply outputs by setting their
respective EN_L+ register bits high.
CQ Line Driver Outputs
Enable the CQ line drivers either by input pin (using the
TXEN turrets and/or jumpers JP1/3/7/9) or via the SPI
interface(bysettingDRVENregisterbitshigh).SeeTable2.
Table 2. CQ Driver Mode Configuration
JP1/3/7/9
SETTING
TXEN
TURRET
DRVEN
BIT
CQ DRIVER
MODE
GND
VL
X
EXT
X
X
X
L/H
0
X
1
0
OFF
ON
ON
OFF/ON
Control the output CQ states using the TXD turrets and/
or jumpers JP2/4/8/10. See Table 3.
Table 3. CQ Driver Output Level Configuration
JP2/4/8/10
SETTING
TXD
TURRET
DRVEN
BIT
CQ DRIVER
MODE*
CQ
LEVEL
GND
GND/VL
EXT
DB9
X
X
L/H
X
X
X
X
H/L**
OFF
ON
ON
ON
L
H/L
H/L
H/L
* From Table 2
** RS232 transceiver U2 inverts
Alternatively, operate the CQ drivers solely via the SPI
interface by tying TXD low and controlling the DRVEN
register bits. This method is suitable for SIO mode and
switching at or below COM2 data rates (38.4kb/s).
TVS Protection
The CQ and L+ pins are protected by 36V TVS diodes for
cable-driving applications.
Serial Port
A DB9 connector enables CQ data to be sent (for one or
more ports) and received (for one port) using PC software
such as a serial terminal program. Jumper JP5 enables
the required RS-232 transceiver.
Select the desired combination of drivers by setting one
or more of JP2/4/8/10 to the DB9 position. Select one CQ
receiver using JP6.
L+ Isolation
If L+ isolation is not needed, Schottky diodes D1-D4 may
be replaced with 0Ω resistors.
Interrupts
The LTC2874 includes an open-drain interrupt line for
signaling the host controller when it needs service. This
signal is accessible on the DC1880A board at the IRQ test
point. An LED is also included for convenience.

5
dc1880af
DEMO MANUAL DC1880A
aDDitional information
Jumpers
JP1/3/7/9: Port 4/3/2/1 CQ Driver Enables. See Table 2.
Default position VL.
JP2/4/8/10: Port 4/3/2/1 Data Input to CQ Driver. See
Table 3. Default position GND.
JP6: RXDn COM Port Select. Determines which receiver
output (RXD1/2/3/4, if any) is connected to the serial port.
Default position RXD1.
JP5: COM PORT Enable. Connects RS232 transceiver U2
to VL logic supply. Default position ON.
JP11: VL Select. Programs LDO voltage to 2.9V(OPEN),
3.3V, 5V, or 5.5V. Default position 5V.
JP12: LDO On. Enables LDO which derives VL logic sup-
ply from VDD supply voltage input. Default position ON.
JP13: GND Shield. Shorts shields of J5-8 to GND. Default
position OPEN.

6
dc1880af
DEMO MANUAL DC1880A
using the Dc1880a software
Introduction
Linear Technology’s QuikEval software provides a quick
and easy way to evaluate most aspects of LTC2874 opera-
tion. It operates a SPI interface that reads or writes from
the 14 onboard registers via a DC590 serial controller.
Install QuikEval BEFORE connecting the DC1880A to the
USB port of the PC. Download and run the installation
program from http://www.linear.com/software and follow
the onscreen instructions. The LTC2874 GUI will launch
automatically when the PC begins communicating with
the DC1880A via the serial controller. Thereafter, start
the GUI by running QuikEval from:
C:\Program Files\LTC\QuikEval\quikeval.exe
If the QuikEval software was installed previously, update
it to the latest version using Tools > Update Program.
The LTC2874 GUI is composed of a main window having
three tabs, and a Register Map window. The Ports tab
(Figure2)containscontrolsandmonitorsthatareuniqueto
eachindividual port.The Timersand Globalstab (Figure3)
contains controls and monitors that are common to all
ports. The Events tab (Figure 4) provides access to event
monitoringregisters. The Register Map window(Figure 5)
provides access to all register bits via an alternate format.
TheLTC2874GUIbeginscommunicatingwiththeDC1880A
automatically. Once running, it continuously polls the
LTC2874 registers to monitor status.
Connect/Disconnect Button
TheDisconnectbuttondisablestheSPIinterface and most
of the GUI. The Connect button restarts SPI polling and
activates the complete GUI.
Reset Button
This button issues a SPI Reset command, returning all
registers to default values.
Events Tab
This tab contains lamps that map to Event Register bits.
A lamp that is on indicates that the corresponding bit in
the LTC2874 Event Register has been set. Clicking on a
lamp will clear the Event bit if the condition no longer
persists. Event Register behavior is sticky, meaning each
lamp stays on until cleared.
The check boxes control which events will cause IRQ to
signal.
Register Map
Thiswindowpresentsallregisterbitsinanalternateformat.
Change register values directly by clicking on individual
bits, using arrow widgets, or by entering numeric values.
Changed bits appear yellow until either committed to the
LTC2874 by pressing the Write and Update button, or
clearedbypressingtheDiscardUnwrittenChangesbutton.
TheSaveCurrentValuesbuttonsavestheLTC2874register
values to a text file. The Load Saved Values button loads
theregister values from onesuchfileintotheRegisterMap
window. (Write and Update will then configure LTC2874
accordingly.)
Running QuikEval GUI Using Linduino One
The QuikEval GUI software for DC1880A may be operated
using a Linduino One (DC2026) with the DC590 emulator
sketchinplaceoftheDC590.WhenusingthisUSB-isolated
Arduino-compatibledemonstrationboard,settheDC1880A
LDO to 5V (JP11=5.0V) or disable it (JP12=OPEN).

7
dc1880af
DEMO MANUAL DC1880A
using the Dc1880a software
Figure 2. Main Window, Ports Tab

8
dc1880af
DEMO MANUAL DC1880A
using the Dc1880a software
Figure 3. Main Window, Timers and Globals Tab

9
dc1880af
DEMO MANUAL DC1880A
using the Dc1880a software
Figure 4. Main Window, Events Tab
Figure 5. Register Map Window

10
dc1880af
DEMO MANUAL DC1880A
troubleshooting guiDe
1. Problem: LTC2874 program doesn't download and
install automatically.
Solution: Get the latest QuikEval software either by
updating QuikEval from its pull-down menu (Tools >
Update Program), or by installing the latest version
directly from: www.linear.com/software.
2. Problem: DC590 controller board not detected.
(Error 1)
Solution: Connect to PC using USB A/B cable.
3. Problem: LTC2874 not detected. (Error 2)
Solution: Ensure that the DC590 ribbon cable is con-
nected and that VL power is applied. See Table 1.
4. Problem: Unsuccessful communication with the
LTC2874. (Error 5)
Solution: Check DC590 ribbon and USB connections.
Usually, this error indicates that one was disconnected
while the program was running.
5. Problem: Invalid value read from the LTC2874.
(Error 6)
Solution: Ensure VL supply power is applied correctly.
ReferringtoTable1,checkLDOjumperontheDC1880A
and JP6 on the DC590.
6. Problem: GUI is gray-colored and inactive.
Solution: Press Connect button.