View detail for ATWINC3400 IEEE 802.11 b/g/n + BLE4.0 Combo SoC for IoT Applications - Hardware Design Guidelines

ATWINC3400
IEEE 802.11 b/g/n + BLE4.0 Combo SoC for IoT
Applications - Hardware Design Guidelines
USER GUIDE
VDDIO
VBAT
Antenna
Chip_En
Reset_n
Wake
SPI
IRQn
ATWINC3400
802.11 B/G/N SOC
+BLE 4.0
Balun
UART
26 MHz
GPIO
Block Diagram
Introduction
This document details the hardware design guidelines for a customer to design the ATWINC3400 IC onto
their board.
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
Ta bl e of Conte nts
1
Reference Schematic................................................................................................... 3
1.1
2
Notes on Interfacing to the ATWINC3400 ................................................................... 4
2.1
2.2
2.3
2.4
3
Schematic.............................................................................................................................................. 3
Programmable Pull-up Resistors ........................................................................................................... 4
Restrictions for Power States ................................................................................................................ 5
Power-up/down Sequence .................................................................................................................... 5
Digital I/O Pin Behavior during Power-up Sequences ........................................................................... 6
Placement and Routing Guidelines ............................................................................ 7
3.1
3.2
3.3
3.4
Power and Ground ................................................................................................................................ 7
RF Traces and Components ................................................................................................................. 7
Sensitive Routes ................................................................................................................................... 8
3.3.1 Signals ...................................................................................................................................... 8
3.3.2 Supplies .................................................................................................................................... 8
Additional Suggestions .......................................................................................................................... 9
4
Interferers ..................................................................................................................... 9
5
Thermal Considerations ............................................................................................ 10
6
External Interfaces ..................................................................................................... 11
6.1
6.2
6.3
General .............................................................................................................................................. 11
SPI Interface........................................................................................................................................ 12
6.2.1 Overview ................................................................................................................................. 12
6.2.2 SPI Timing .............................................................................................................................. 13
6.2.3 SPI PCB Trace Constraints .................................................................................................... 14
UART Interface.................................................................................................................................... 14
7
Antenna
8
FCC, TELEC, and ETSI Compliance.......................................................................... 15
9
Reference Documentation and Support ................................................................... 16
9.1
................................................................................................................... 15
Reference Documents ......................................................................................................................... 16
10 ATMEL EVALUATION BOARD/KIT IMPORTANT NOTICE AND DISCLAIMER ........ 17
11 Revision History ........................................................................................................ 18
2
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
2
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
1
Reference Schematic
1.1
Schematic
Figure 1-1 shows the reference schematic for a system using the ATWINC3400. Note that there are
several 0Ω resistors (R1-R12) shown in series with signals to the chip. These are place holders in case
filtering of these lines is necessary due to high frequency in band (2.4GHz) noise on these lines, which
can get into the RF path and degrade receiver sensitivity. If the signals coming from the host MCU are
noise free, then these placeholders are not required and can be removed.
Figure 1-1.
Reference Schematic
Figure 1-2.
Bill of Materials
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
3 3
2
Notes on Interfacing to the ATWINC3400
2.1
Programmable Pull-up Resistors
The ATWINC3400 provides programmable pull-up resistors on various pins. The purpose of these
resistors is to keep any unused input pins from floating, which can cause excess current to flow through
the input buffer from the VDDIO supply. Any unused chip pin on the ATWINC3400 should leave these
pull-up resistors enabled so the pin will not float. The default state at power up is for the pull-up resistor to
be enabled. However, any pin used should have the pull-up resistor disabled. The reason for this is that if
any pins are driven to a low level while the ATWINC3400 is in the low-power sleep state, current will flow
from the VDDIO supply through the pull-up resistors and increase the current consumption of the chip.
Since the value of the pull-up resistor is approximately 100kΩ, the current through any pull-up resistor
driven low will be VDDIO/100kΩ. For VDDIO = 3.3V, the current through each pull-up resistor driven low
would be approximately 3.3V/100kΩ = 33µA. Pins which are used and have had the programmable pullup resistor disabled should always be actively driven to either a high or low level and not be allowed to
float.
See the ATWINC3400 Programming Guide for information on enabling/disabling the programmable pullup resistors.
Figure 2-1.
ATWINC3400 Pad ESD Structure
This shows why it is important that any time Chip_En to the chip is low, all pins interfacing to the chip
must not be driven or pulled high. They should either be set to a low level or high impedance state. This
means that if any external pull-up resistors are attached to any pins they should be disconnected from the
supply when Chip_En is low.
4
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
4
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
Figure 2-2.
2.2
Current Path through ESD Diode
Restrictions for Power States
When no power is supplied to the device, i.e., the DC/DC Converter output and VDDIO are both off (at
ground potential). In this case, a voltage cannot be applied to the device pins because each pin contains
an ESD diode from the pin to supply. This diode will turn on when voltage higher than one diode-drop is
supplied to the pin.
If a voltage must be applied to the signal pads while the chip is in a low-power state, the VDDIO supply
must be on, so the SLEEP or Power_Down state must be used.
Similarly, to prevent the pin-to-ground diode from turning on, do not apply a voltage that is more than one
diode-drop below ground to any pin.
2.3
Power-up/down Sequence
The power-up/down sequence for ATWINC3400A is shown in Figure 2-3. The timing parameters are
provided in Table 2-1.
Figure 2-3.
Power Up/Down Sequence
VBATT
tA
t A'
VDDIO
tB
t B'
CHIP_EN
tC
t C'
RESETN
XO Clock
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
5 5
Table 2-1.
2.4
Power-up/down Sequence Timing
Parameter
Min.
Max.
Unit
Description
Notes
tA
0
ms
VBATT rise to VDDIO rise
VBATT and VDDIO can rise simultaneously
or can be tied together. VDDIO must not
rise before VBATT.
tB
0
ms
VDDIO rise to CHIP_EN rise
CHIP_EN must not rise before VDDIO.
CHIP_EN must be driven high or low, not
left floating.
tC
5
ms
CHIP_EN rise to RESETN rise
This delay is needed because XO clock
must stabilize before RESETN removal.
RESETN must be driven high or low, not
left floating.
tA’
0
ms
VDDIO fall to VBATT fall
VBATT and VDDIO can fall simultaneously
or can be tied together. VBATT must not
fall before VDDIO.
tB’
0
ms
CHIP_EN fall to VDDIO fall
VDDIO must not fall before CHIP_EN.
CHIP_EN and RESETN can fall simultaneously.
tC’
0
ms
RESETN fall to VDDIO fall
VDDIO must not fall before RESETN. RESETN and CHIP_EN can fall simultaneously.
Digital I/O Pin Behavior during Power-up Sequences
Table 2-2 represents digital I/O pin states corresponding to device power modes.
Table 2-2.
Digital I/O Pin Behavior in Different Device States
Device state
6
Output
driver
Input
driver
Pull-up/down
resistor (96kΩ)
VDDIO
CHIP_EN
RESETN
Power Down:
core supply off
High
Low
Low
Disabled
(Hi-Z)
Disabled
Disabled
Power-On Reset:
core supply on, hard reset on
High
High
Low
Disabled
(Hi-Z)
Disabled
Enabled
Power-On Default:
core supply on, device out of
reset but not programmed yet
High
High
High
Disabled
(Hi-Z)
Enabled
Enabled
On Sleep/
On Transmit/
On Receive:
core supply on, device programmed by firmware
High
High
High
Programmed
by firmware
for each pin:
Enabled or
Disabled
Opposite
of output
driver
state
Programmed by
firmware for
each pin: Enabled or Disabled
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
6
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
3
Placement and Routing Guidelines
It is critical to follow the recommendations listed below to achieve the best RF performance:
3.1

The board should have a solid ground plane. The center ground pad of the device must be solidly
connected to the ground plane by using a 3 x 3 grid of vias.

Keep away from antenna, as far as possible, large metal objects to avoid electromagnetic field
blocking

Do not enclose the antenna within a metal shield

Keep any components which may radiate noise or signals within the 2.4 – 2.5GHz frequency band
far away from the antenna or better yet, shield those components. Any noise radiated from the main
board in this frequency band will degrade the sensitivity of the chip.
Power and Ground
Dedicate one layer as a ground plane. Make sure that this ground plane does not get broken up by routes.
Power can route on all layers except the ground layer. Power supply routes should be heavy copper fill
planes to insure the lowest possible inductance. The power pins of the ATWINC3400 should have a via
directly to the power plane as close to the pin as possible. Decoupling capacitors should have a via right
next to the capacitor pin and this via should go directly down to the power plane – that is to say, the
capacitor should not route to the power plane through a long trace. The ground side of the decoupling
capacitor should have a via right next to the pad which goes directly down to the ground plane. Each
decoupling capacitor should have its own via directly to the ground plane and directly to the power plane
right next to the pad. The decoupling capacitors should be placed as close to the pin that it is filtering as
possible.
3.2
RF Traces and Components
The RF traces that go from the ATWINC3400 to the balun must be 50Ω differential controlled impedance.
These are pins 5 and 6 of the ATWINC3400. The route from the balun to the antenna connector must be
a 50Ω controlled impedance trace. These controlled impedance traces must reference a ground plane on
a lower layer. To achieve 50Ω impedance, a typical design might be 20 mil traces referenced to a ground
plane on an inner layer which is 10.7 mils below the traces. This must be adjusted depending on the
dielectric and copper weight used. No other traces must route through the RF area on layers between the
RF traces and the ground reference plane. In fact, try not to route any other traces in the RF area on any
layer. This ground reference plane must extend entirely under the tuner.
Be sure to add as many ground vias as possible, tying all ground layers together (ground stitching) all
along the RF traces and throughout the area where the RF traces are routed. Add at least two ground vias
for every ground pad around the RF components. Place ground vias all along the RF traces on either
side.
Tie the center ground pad of the ATWINC3400 to the inner ground layer using a grid of nine vias. The
ground path going from the ground pad down to the ground plane must be absolutely as low impedance
as possible.
Do not use thermal relief pads for the ground pads of all components in the RF path. These component
pads must be completely filled in with ground copper.
Be sure to place the matching components and balun as close to the RFIOP and RFION pins as possible
(these are named C33, C23, C25, C17, C32, L8, and L9 in the reference schematic). Figure 3-1 shows
the placement and routing of these components. Note that they are placed as close as possible to the
ATWINC3400’s pins 5 and 6. The components used for this design are 0201. Note that the width of the
route matches the width of the component pads. This will avoid impedance discontinuities which would
occur if there is a large mismatch in trace width versus the component pad size.
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
7 7
Figure 3-1.
Placement and Routing of Balun and Matching Components
Be sure the route from the antenna to the ATWINC3400 is as short as possible and is completely isolated
from all other signals on the board. No signals should route under this trace on any layer of the board.
Make sure that all digital signals that may be toggling while the ATWINC3400 active are placed as far
away from the antenna as possible. No connectors which have digital signals going to them should be
near the antenna. All digital components and switching regulators on the board should be shielded so they
do not radiate noise that is picked up by the antenna.
In summary, make sure anything that switches is shielded and kept away from the antenna, the
ATWINC3400 or the route from the ATWINC3400 to the antenna.
3.3
Sensitive Routes
3.3.1
Signals
The following signals are very sensitive to noise and you must take care to keep them as short as
possible and keep them isolated from all other signals by routing them far away from other traces or using
ground to shield them. Be sure that they are also isolated from noisy traces on the layers above them and
below them:
XO_N
XO_P
RFIOP
RFION
3.3.2
Supplies
The following power supply pins for the ATWINC3400 are sensitive to noise and care should be taken to
isolate the routes to these pins from other noisy signals both on the same layer as the route and on layers
above and below. Use ground between these sensitive signals to isolate them from other signals. It is
important that the decoupling capacitors for these supplies are placed as close to the ATWINC3400 pin as
8
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
8
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
possible. This is necessary to reduce the trace inductance between the capacitor and ATWINC3400
power pin to an absolute minimum:
VDDRF_RX (pin 1)
VDDRF_TX (pin 3)
VDD_AMS (pin 2)
VDD_SXDIG (pin 45)
VDD_VCO (pin 46)
Additionally, while the VDDC (pin 18) and VBAT_BUCK (pin 24) supplies are not sensitive to picking up
noise, they are noise generating supplies. Therefore, be sure to keep the decoupling capacitors for these
supply pins as close as possible to the VDDC and VBAT_BUCK pins and make sure that the routes for
these supplies stay far away from sensitive pins and supplies.
3.4
Additional Suggestions
Make sure that traces route directly through the pads of all filter capacitors and not by way of a stub route.
The following routes are extremely critical and should be routed first. C) is a power route and should be a
heavy copper route. These routes must not have anything above, below, or to the side of them except
ground. They must be as short as possible. Make sure that the filter capacitor for these pins is placed right
next to the pin.
A.
The 50Ω differential pair from ATWINC3400 pins 5 and 6 to the balun. Be sure this route is as short
as possible and that both routes of the differential pair are matched in length.
B.
The 50Ω unbalanced route from the balun to the antenna.
C.
The routes to the XO_P and XO_N pins (pins 43 and 44). These must be isolated with ground
above, below, and to the sides of the routes.
D.
The route from ATWINC3400 pin 25 (VSW) to the 15nH inductor (L5) must be as short and wide as
possible. Make sure this inductor is placed right next to pin 25. The route from the other side of this
inductor to the 1.0µH inductor (L1) must also be as short and heavy as possible. Then the route
from L1 to the 10µF capacitor (C10) and to pin 26 must also be as short and heavy as possible.
E.
The loop created from ATWINC3400 pin 25 through the inductors, the capacitor, and back to pin 26
must be as small as possible.
F.
Make sure the ground return path from the 10µF capacitor connected to pin 26 back to the ground
pad of the ATWINC3400 is as short and wide as possible. This is critical. The ground return path
must have extremely low inductance. Failure to provide a short, heavy ground return between the
capacitor and the ATWINC3400 ground pad will result in incorrect operation of the on chip switching
regulator.
Be sure to place the power supply decoupling capacitors so that there is a capacitor very close to each
power supply pin of the device. This requires making the copper as short and wide as possible – use
copper fills for the power supply routing from the pins to the filter capacitors, not narrow traces.
4
Interferers
One of the biggest problems with RF receivers is poor performance due to interferers on the board
radiating noise into the antenna or coupling into the RF traces going to input LNA. Care must be taken to
make sure that there is no noisy circuitry placed anywhere near the antenna or the RF traces. All noise
generating circuits should also be shielded so they do not radiate noise that is picked up by the antenna.
Also make sure that no traces route underneath the RF portion of the ATWINC3400 and that no traces
route underneath any of the RF traces from the antenna to the ATWINC3400 input. This applies to all
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
9 9
layers. Even if there is a ground plane on a layer between the RF route and another signal, the ground
return current will flow on the ground plane and couple into the RF traces.
5
Thermal Considerations
Table 5-1 lists the thermal resistance from junction to ambient (JA) and from junction to case (JC) for
6x6 48L QFN.
Table 5-1.
Thermal Resistance from Junction to Ambient
Package
5x5mm 40L QFN
JA
JC
29.5ºC/W
3.7ºC/W
Junction-to-ambient thermal resistance JA is a one-dimensional value that measures the conduction of
heat from the junction (hottest temperature on die) to the environment near the package. The generated
heat on the die surface reaches the immediate environment along two paths: (1) convection and radiation
off the exposed surface of the package and (2) conduction into and through the test board followed by
convection and radiation off the exposed board surfaces. JA reported here assumes the package is
mounted on a board with two signal layers and two internal planes (2s2p).
10
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
1
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
0
6
External Interfaces
6.1
General
The Digital Pad Characteristics are given in Table 6-1.
Table 6-1.
Digital Pad Characteristics
Symbol
Characteristics
Min.
Typ.
Max.
Unit
VDDIOL (2)
I/O Supply Voltage Low Range
1.62
1.80
2.00
V
VDDIOM (2)
I/O Supply Voltage Mid-Range
2.00
2.50
3.00
V
I/O Supply Voltage High Range
3.00
3.30
3.60
V
Battery Supply Voltage
2.5 (4)
3.6
4.2
V
Operating Temperature
-40
85
ºC
VDDIOH
(2)
VBATT (3)
Notes:
1.
2.
3.
4.
Table 6-2.
Refer to the datasheet for details of power connections.
I/O supply voltage is applied to the following pins: VDDIO_A, VDDIO_0, and VDDIO_1.
Battery supply voltage is applied to following pins: VDDBATT_PPA/PA and VBATT_BUCK.
Device is functional across this range of voltages; however, optimal RF performance is guaranteed for
VBATT in the range 3.0V < VBATT < 4.2V.
VDDIO Conditions
VDDIO condition
VDDIOL
Characteristics
Min.
Max.
Unit
Input Low Voltage VIL
-0.30
0.60
V
Input High Voltage VIH
VDDIO-0.60
VDDIO+0.30
V
0.45
V
Output Low Voltage VOL
VDDIOM
Output High Voltage VOH
VDDIO-0.50
V
I2C Pad Drive Strength (1)
4
mA
All other Digital Pad Drive Strength
2
mA
Input Low Voltage VIL
-0.30
0.63
V
Input High Voltage VIH
VDDIO-0.60
VDDIO+0.30
V
0.45
V
Output Low Voltage VOL
VDDIOH
Output High Voltage VOH
VDDIO-0.50
V
I2C Pad Drive Strength (1)
8
mA
All other Digital Pad Drive Strength
4
mA
Input Low Voltage VIL
-0.30
0.65
V
Input High Voltage VIH
VDDIO-0.60
VDDIO+0.30
(up to 3.60)
V
0.45
V
Output Low Voltage VOL
Output High Voltage VOH
2
I C Pad Drive Strength
(1)
All other Digital Pad Drive Strength
All
Output Loading
VDDIO-0.50
V
12
mA
6
mA
20
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
pF
11 1
1
VDDIO condition
All
Note:
Characteristics
Min.
Digital Input Load
1.
Max.
Unit
6
pF
I2C Pad Drive Strength applies to the following pins: I2C_SDA, I2C_SCL.
6.2
SPI Interface
6.2.1
Overview
ATWINC3400 has a Serial Peripheral Interface (SPI) that operates as a SPI slave. The SPI interface can
be used for control and for serial I/O of 802.11 data. The SPI pins are mapped as shown in Table 6-3. The
SPI is a full-duplex slave-synchronous serial interface that is available immediately following reset when
pin 8 (SPI_CFG) is tied to VDDIO.
Table 6-3.
SPI Interface Pin Mapping
Pin #
SPI Function
8
CFG: Must be tied to VDDIO for ATWINC3400
32
SSN: Active Low Slave Select
34
MOSI (RXD): Serial Data Receive
30
SCK: Serial Clock
31
MISO (TXD): Serial Data Transmit
When the SPI is not selected, i.e., when SSN is high, the SPI interface will not interfere with data transfers
between the serial-master and other serial-slave devices. When the serial slave is not selected, its
transmitted data output is buffered, resulting in a high impedance drive onto the MISO line.
The SPI interface responds to a protocol that allows an external host to read or write any register in the
chip as well as initiate DMA transfers.
The SPI SSN, MOSI, MISO, and SCK pins of the ATWINC3400 have internal programmable pull-up
resistors. These resistors should be programmed to be disabled. Otherwise, if any of the SPI pins are
driven to a low level while the ATWINC3400 is in the low-power sleep state, current will flow from the
VDDIO supply through the pull-up resistors, increasing the current consumption of the chip.
12
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
1
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
2
6.2.2
SPI Timing
The SPI timing is provided in Figure 6-1 and Table 6-4.
Figure 6-1.
SPI Timing Diagram (SPI Mode CPOL=0, CPHA=0)
fSCK
tLH
tWH
SCK
tWL
tHL
TXD
t ODLY
RXD
tISU
SSN
SPI Master
tIHD
tSSODLY
SSN
SPI Slave
t SUSSN
Table 6-4.
t HDSSN
SPI Slave Timing Parameters
Parameter
Symbol
Min.
Max.
Unit
48
MHz
Clock Input Frequency
fSCK
Clock Low Pulse Width
tWL
5
ns
Clock High Pulse Width
tWH
5
ns
Clock Rise Time
tLH
5
ns
Clock Fall Time
tHL
5
ns
Input Setup Time
tISU
5
ns
Input Hold Time
tIHD
5
ns
Output Delay
tODLY
0
Slave Select Setup Time
TSUSSN
5
ns
Slave Select Hold Time
tHDSSN
5
ns
20
Remarks
ns
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
13 1
3
6.2.3
SPI PCB Trace Constraints
In general, the SPI PCB trace layout must ensure that the total capacitance (trace and load of other pin)
on the SPI lines (SPI_RXD, SPI_SSN, SPI_TXD, and SPI_SCK) are less than the maximum pin
capacitance of 20pF (see Section 6.1). As this is heavily dependent on the board type and lithography, no
single constraint of trace length can be given. It is, however, preferable to minimize the trace length as
much as possible. For further guidance, consult your Atmel® FAE. Be sure to have all information on the
application PCB layout design rules.
6.3
UART Interface
The ATWINC3400 has a Universal Asynchronous Receiver/Transmitter (UART) interface available on
pins 14 and 15. It can be used for control or data transfer if the baud rate is sufficient for a given
application. The UART is compatible with the RS-232 standard, where ATWINC3400 operates as Data
Terminal Equipment (DTE). It has a two-pin RXD/TXD interface.
The UART features programmable baud rate generation with fractional clock division, which allows
transmission and reception at a wide variety of standard and non-standard baud rates. The UART input
clock is selectable between 10MHz, 5MHz, 2.5MHz, and 1.25MHz. The clock divider value is
programmable as 13 integer bits and three fractional bits (with 8.0 being the smallest recommended value
for normal operation). This results in the maximum supported baud rate of 10MHz / 8.0 = 1.25MBd.
The UART can be configured for seven or eight bit operation, with or without parity, with four different
parity types (odd, even, mark, or space), and with one or two stop bits. It also has RX and TX FIFOs,
which ensure reliable high speed reception and low software overhead transmission. FIFO size is 4 x 8 for
both RX and TX direction. The UART also has status registers showing the number of received characters
available in the FIFO and various error conditions, as well as the ability to generate interrupts based on
these status bits.
An example of UART receiving or transmitting a single packet is shown in Figure 6-2. This example shows
7-bit data (0x45), odd parity, and two stop bits.
See the ATWINC3400 Programming Guide for information on configuring the UART.
Figure 6-2.
14
Example of UART RX or TX Packet
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
1
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
4
7
Antenna
Make sure to choose an antenna that covers the proper frequency band, 2.400GHz to 2.500GHz. Talk to
the antenna vendor and make sure he understands the full frequency range that must be covered by the
antenna.
Make sure the antenna is designed for a 50Ω system.
Make sure the PCB pad that the antenna is connected to is properly designed for 50Ω impedance. This is
extremely important. The antenna vendor must specify the pad dimensions, the spacing from the pad to
the ground reference plane, and the spacing from the edges of the pad to the ground fill on the same layer
as the pad. Also, since the ground reference plane for the 50Ω trace going from the antenna pad to the
ATWINC3400 will probably be on a different layer than the ground reference for the antenna pad, make
sure the pad design has a proper transition from the pad to the 50Ω trace.
Make sure that the antenna matching components are placed as close to the antenna pad as possible.
The antenna cannot be properly matched if the matching components are far away from the antenna.
8
FCC, TELEC, and ETSI Compliance
The reference design provided is compliant with FCC, TELEC, and ETSI regulations. No calibrations are
needed by the device maker if the 26MHz crystal used meets the 802.11 requirements (±20ppm). For
crystals variations outside this range, consult your Atmel FAE.
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
15 1
5
9
Reference Documentation and Support
9.1
Reference Documents
Atmel offers a set of collateral documentation to ease integration and device ramp.
Table 9-1 shows a list of documents available on Atmel web or integrated into development tools.
Table 9-1.
Reference Documentation
Title
Content
Datasheet
Design Files Package
User Guide, Schematic, PCB layout, Gerber, BOM and System notes on: RF/Radio Full
Test Report, radiation pattern, design guidelines, temperature performance, ESD.
Platform Getting
started Guide
How to use package: Out of the Box starting guide, HW limitations and notes, SW Quick
start guidelines
HW Design Guide
This document
SW Design Guide
Integration guide with clear description of: High level Arch, overview on how to write a
networking application, list all API, parameters and structures. Features of the device,
SPI/handshake protocol between device and host MCU, with flow/sequence/state diagram, timing.
SW Programmer
guide
Explain in details the flow chart and how to use each API to implement all generic use
cases (e.g. start AP, start STA, provisioning, UDP, TCP, http, TLS, p2p, errors management, connection/transfer recovery mechanism/state diagram) - usage and sample application note
For a complete listing of development-support tools and documentation, visit http://www.atmel.com/ or
contact the nearest Atmel field representative.
16
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
1
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
6
10
ATMEL EVALUATION BOARD/KIT IMPORTANT NOTICE AND
DISCLAIMER
This evaluation board/kit is intended for user's internal development and evaluation purposes only. It is
not a finished product and may not comply with technical or legal requirements that are applicable to
finished products, including, without limitation, directives or regulations relating to electromagnetic
compatibility, recycling (WEEE), FCC, CE or UL. Atmel is providing this evaluation board/kit “AS IS”
without any warranties or indemnities. The user assumes all responsibility and liability for handling and
use of the evaluation board/kit including, without limitation, the responsibility to take any and all
appropriate precautions with regard to electrostatic discharge and other technical issues. User indemnifies
Atmel from any claim arising from user's handling or use of this evaluation board/kit. Except for the limited
purpose of internal development and evaluation as specified above, no license, express or implied, by
estoppel or otherwise, to any Atmel intellectual property right is granted hereunder. ATMEL SHALL NOT
BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMGES RELATING
TO USE OF THIS EVALUATION BOARD/KIT.
ATMEL CORPORATION
1600 Technology Drive
San Jose, CA 95110
USA
ATWINC3400 IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
17 1
7
11
18
Revision History
Doc Rev.
Date
42564A
01/2016
Comments
Initial document release.
ATWINC3400
IEEE 802.11 b/g/n Combo SoC for IoT Applications HW Design Guidelines [USER GUIDE]
1
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
8
Atmel Corporation
1600 Technology Drive, San Jose, CA 95110 USA
T: (+1)(408) 441.0311
F: (+1)(408) 436.4200
│
www.atmel.com
© 2016 Atmel Corporation. / Rev.: Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016.
Atmel®, Atmel logo and combinations thereof, Enabling Unlimited Possibilities®, and others are registered trademarks or trademarks of Atmel Corporation in U.S. and
other countries. ARM®, ARM Connected® logo, and others are the registered trademarks or trademarks of ARM Ltd. Other terms and product names may be
trademarks of others.
DISCLAIMER: The information in this document is provided in connection with Atmel products. No license, express or implied, b y estoppel or otherwise, to any intellectual property right
is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN THE ATMEL TERMS AND CONDITIONS OF SALES LOCATED ON THE
ATMEL WEBSITE, ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY RELATING TO ITS PRODUCTS
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON -INFRINGEMENT. IN NO EVENT
SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE, SPECIAL OR INCIDENTAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES
FOR LOSS AND PROFITS, BUSINESS INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT , EVEN IF ATMEL
HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Atmel makes no representations or warranties with respect to the accuracy or completeness of the contents of this
document and reserves the right to make changes to specifications and products descriptions at any time without notice. Atmel does not make any commitment to update the information
contained herein. Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in, auto motive applications. Atmel products are not intended,
authorized, or warranted for use as components in applications intended to support or sustain life.
SAFETY-CRITICAL, MILITARY, AND AUTOMOTIVE APPLICATIONS DISCLAIMER: Atmel products are not designed for and will not be used in conne ction with any applications where
the failure of such products would reasonably be expected to result in significant personal injury or death (“Safety-Critical Applications”) without an Atmel officer's specific written consent.
Safety-Critical Applications include, without limitation, life support devices and systems, equipment or systems for the o peration of nuclear facilities and weapons systems. Atmel
products are not
designed nor intended
for use
in military
or aerospace
environments
unless specifically
desi gnated
by Atmel asUSER
military-grade.
Atmel products are not
ATWINC3400
IEEE
802.11
b/g/n
Comboapplications
SoC fororIoT
Applications
HW Design
Guidelines
GUIDE
designed nor intended for use in automotive applications
unless specifically designated by Atmel as automotive -grade.
Atmel-42564A-ATWINC3400-IEEE802.11bgn-Combo-SoC-for-IoT-Applications-HW-Design-Guidelines_UserGuide_01/2016
[
]
19 1
9