UG-400 Datasheet, PDF (9/20 Pages) Analog Devices – Plug and play system evaluation

Hardware User Guide
UG-400
ISOLATED SPI
Two isolated SPI ports are implemented using the ADuM3401,
the ADuM3402 iCoupler signal isolators, and the ADuM5000
isoPower isolated dc-to-dc converter. The isolated SPI0 imple-
mentation on the ezLINX hardware uses the ADuM3401. The
ADuM3401 connects to SPI0 of the Blackfin ADSP-BF548 and
is used to isolate the SCLK, MISO, SSEL1, and MOSI lines. The
ADuM3402 is used for isolating the SPI slave select lines. Figure 8
shows a circuit diagram of the implementation of isolated SPI1
using the ADuM3401, ADuM3402, and ADuM5000 on the
ezLINX hardware.
The isolated SPI2 implementation on the ezLINX hardware uses
the ADuM3401. The ADuM3401 connects to SPI2 of the ADSP-
BF548 and is used to isolate the SCLK, MISO, SSEL1, and MOSI
lines. The ADuM3402 is used for isolating the SPI slave select
lines. Figure 9 shows a circuit diagram of the implementation of the
isolated SPI2 using the ADuM3401, ADuM3402, and ADuM5000
on the ezLINX hardware.
The VDD1 pin (Pin 1) of the ADuM3401 and ADuM3402 and
the VDD1 pins (Pin 1 and Pin 7) of the ADuM5000 are powered
by 3.3 V. The ADuM5000 generates an isolated 3.3 V, which is
used to supply power to the VDD2 pin (Pin 16) of the ADuM3401
and ADuM3402.
Two 7-pin screw terminal connectors, J10 and J25, are used for easy
access to the SPISCK (Pin 1 of J10 and J25), SPIMOSI (Pin 2 of J10
and J25), SPISEL1/SPISS (Pin 3 of J10 and J25), SPIMISO (Pin 4
of J10 and J25), SPISEL2 (Pin 5 of J10 and J25), SPISEL3 (Pin 6 of
J10 and J25), and SPI_ISO_GND (Pin 7 of J10 and J25) signals.
To connect the isolated SPI0 as a master, connect Jumpers JP5,
JP7, JP9, JP11, JP13, JP15, JP21, and JP36 while leaving Jumpers
JP6, JP8, JP10, JP12, JP14, JP16, JP20, and JP37 open (see the
Warnings section). To connect the isolated SPI0 as a slave, connect
Jumpers JP6, JP8, JP10, JP12, JP14, JP16, JP20, and JP37 while
leaving Jumpers JP5, JP11, JP13, JP15, JP21, and JP36 (see the
Warnings section).
Table 1. Isolated SPI0 Connections
Jumper
SPI0 Master
JP5
Connect
JP6
Open
JP7
Connect
JP8
Open
JP9
Connect
JP10
Open
JP11
Connect
JP12
Open
JP13
Connect
JP14
Open
JP15
Connect
JP16
Open
JP20
Open
JP21
Connect
JP36
Connect
JP37
Open
SPI0 Slave
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Connect
Open
Open
Connect
To connect the isolated SPI2 as a master, connect Jumpers JP22,
JP24, JP26, JP28, JP30, JP32, JP35, and JP38 while leaving
Jumpers JP23, JP25, JP27, JP29, JP31, JP33, JP34, and JP39 open
(see the Warnings section). To connect the isolated SPI2 as a slave,
connect Jumpers JP23, JP25, JP27, JP29, JP31, JP33, JP34, and
JP39 while leaving Jumpers JP22, JP24, JP26, JP28, JP30, JP32,
JP35, and JP38 open (see the Warnings section).
Table 2. Isolated SPI2 Connections
Jumper
SPI2 Master
JP22
Connect
JP23
Open
JP24
Connect
JP25
Open
JP26
Connect
JP27
Open
JP28
Connect
JP29
Open
JP30
Connect
JP31
Open
JP32
Connect
JP33
Open
JP34
Open
JP35
Connect
JP38
Connect
JP39
Open
SPI2 Slave
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Open
Connect
Connect
Open
Open
Connect
The ADuM5000 contains isoPower technology that uses high
frequency switching elements to transfer power through the
transformer. Special care must be taken during PCB layout to
meet emissions standards. See the AN-0971 Application Note,
Recommendations for Control of Radiated Emissions with
isoPower Devices, for board layout recommendations.
Warnings
JP20 and JP21
JP20 and JP21 should never both be connected because doing
so will create a short circuit between 3.3 V and GND.
JP34 and JP35
JP34 and JP35 should never both be connected because doing
so will create a short circuit between 3.3 V and GND.
Rev. 0 | Page 9 of 20