View detail for ATWINC3400 Wi-Fi/BLE Network Controller - Software Design Guide

ATWINC3400
ATWINC3400 Wi-Fi/BLE Network Controller - Software
Design Guide
User Guide
Introduction
Atmel® SmartConnect ATWINC3400 SoC is an IEEE® 802.11 b/g/n and
Bluetooth® Smart BLE network controller for applications in the Internet-ofThings. It is an ideal add-on to existing MCU solutions bringing Wi-Fi® and
network capabilities through an SPI-to-Wi-Fi interface. The ATWINC3400
connects to any Atmel AVR® or Atmel | SMART™ MCU with minimal resource
requirements.
Features
 Wi-Fi IEEE® 802.11 b/g/n STA and AP modes
 Wi-Fi Protected Setup (WPS)
 Discovery and provisioning via Smartphone using BLE
 Support of WEP and WPA/WPA2 personal security
 Embedded network stack protocols to offload work from the host MCU. This
allows operation with a wide range of MCUs including low end MCUs.
 Embedded TCP/IP stack with BSD-style socket API
 Embedded network protocols
– DHCP client/server
– DNS resolver client
– SNTP client for UTC time synchronization
 Embedded TLS security abstracted behind BSD-style socket API
 HTTP Server for optional provisioning using AP mode
 Ultra-low cost IEEE 802.11 b/g/n RF/PH/MAC SoC
 Ultra-low power Bluetooth SMART (BLE 4.0) SoC with Integrated MCU,
Transceiver, Modem, MAC, PA, TR Switch, and Power Management Unit
 Fast boot from on-chip Boot ROM
 8Mb internal Flash memory
 Low power consumption with different power saving modes
 SPI, I2C, and UART support
 Low footprint host driver with the following capabilities:
– Can run on 8, 16, and 32 bit MCU
– Little and Big endian support
– Consumes about 8KB of code memory and 1KB of data memory on host
MCU
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Table of Contents
1
Icon Key Identifiers .............................................................................................. 7
2
Glossary ................................................................................................................ 7
3
References ............................................................................................................ 7
4
Host Driver Architecture ...................................................................................... 8
4.1
4.2
4.3
4.4
4.5
5
WLAN API ......................................................................................................................................... 8
Socket API ......................................................................................................................................... 8
Host Interface (HIF) ........................................................................................................................... 9
Board Support Package (BSP) .......................................................................................................... 9
Serial Bus Interface ........................................................................................................................... 9
WINC System Architecture ................................................................................ 10
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
6
Bus Interface ................................................................................................................................... 10
Non-volatile Storage ........................................................................................................................ 11
CPUs ............................................................................................................................................... 11
IEEE 802.11 MAC Hardware ........................................................................................................... 11
Bluetooth BLE V4.0 MAC Hardware ................................................................................................ 11
Program Memory ............................................................................................................................. 11
Data Memory ................................................................................................................................... 11
Shared Packet Memory ................................................................................................................... 11
IEEE 802.11 MAC Firmware............................................................................................................ 11
Bluetooth V2.1 MAC Firmware ........................................................................................................ 12
Memory Managers ........................................................................................................................... 12
Power Managements ....................................................................................................................... 12
ATWINC RTOS ............................................................................................................................... 12
ATWINC IoT Library ........................................................................................................................ 13
ATWINC Initialization and Simple Application ................................................. 14
6.1
6.2
6.3
6.4
BSP Initialization.............................................................................................................................. 14
ATWINC Host Driver Initialization .................................................................................................... 14
Socket Layer Initialization ................................................................................................................ 14
ATWINC Event Handling ................................................................................................................. 14
6.4.1 Asynchronous Events ............................................................................................................. 15
6.4.2 Interrupt Handling ................................................................................................................... 15
6.5 Code Example ................................................................................................................................. 16
7
ATWINC Configuration ....................................................................................... 17
7.1
Device Parameters .......................................................................................................................... 17
7.1.1 System Time........................................................................................................................... 17
7.1.2 Firmware and HIF Version ...................................................................................................... 17
7.2 ATWINC Modes of Operation .......................................................................................................... 17
7.2.1 Idle Mode ................................................................................................................................ 18
7.2.2 Wi-Fi Station Mode ................................................................................................................. 18
7.2.3 Wi-Fi Hotspot (AP) Mode ........................................................................................................ 18
7.3 Network Parameters ........................................................................................................................ 19
7.3.1 Wi-Fi MAC Address ................................................................................................................ 19
7.3.2 IP Address .............................................................................................................................. 19
7.4 Power Saving Parameters ............................................................................................................... 19
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7.4.2
8
Power Saving Modes .............................................................................................................. 19
7.4.1.1 M2M_PS_MANUAL ................................................................................................ 20
7.4.1.2 M2M_PS_AUTOMATIC .......................................................................................... 21
7.4.1.3 M2M_PS_H_AUTOMATIC ..................................................................................... 21
7.4.1.4 M2M_PS_DEEP_AUTOMATIC .............................................................................. 21
Configuring Listen Interval and DTIM Monitoring.................................................................... 21
Wi-Fi Station Mode ............................................................................................. 22
8.1
Scan Configuration Parameters....................................................................................................... 22
8.1.1 Scan Region ........................................................................................................................... 22
8.1.2 Scan Options .......................................................................................................................... 22
8.2 Wi-Fi Scan ....................................................................................................................................... 22
8.3 On Demand Wi-Fi Connection ......................................................................................................... 23
8.4 Default Connection .......................................................................................................................... 24
8.5 Wi-Fi Security .................................................................................................................................. 25
8.6 Example Code ................................................................................................................................. 26
9
ATWINC Socket Programming .......................................................................... 27
9.1
Overview ......................................................................................................................................... 27
9.1.1 ATWINC Socket Types ........................................................................................................... 27
9.1.2 Socket Properties ................................................................................................................... 27
9.1.3 Limitations .............................................................................................................................. 27
9.2 ATWINC Sockets API ...................................................................................................................... 27
9.2.1 API Prerequisites .................................................................................................................... 27
9.2.2 Non-blocking Asynchronous Socket APIs .............................................................................. 28
9.2.3 Socket API Functions ............................................................................................................. 28
9.2.3.1 socketInit ................................................................................................................ 28
9.2.3.2 registerSocketCallback ........................................................................................... 28
9.2.3.3 socket ..................................................................................................................... 28
9.2.3.4 connect ................................................................................................................... 28
9.2.3.5 bind ......................................................................................................................... 29
9.2.3.6 listen ....................................................................................................................... 29
9.2.3.7 accept ..................................................................................................................... 29
9.2.3.8 send ........................................................................................................................ 30
9.2.3.9 sendto ..................................................................................................................... 30
9.2.3.10 recv / recvfrom ........................................................................................................ 31
9.2.3.11 close ....................................................................................................................... 31
9.2.3.12 setsockopt .............................................................................................................. 31
9.2.3.13 gethostbyname ....................................................................................................... 31
9.2.4 Summary ................................................................................................................................ 32
9.3 Socket Connection Flow .................................................................................................................. 33
9.3.1 TCP Client Operation ............................................................................................................. 34
9.3.2 TCP Server Operation ............................................................................................................ 35
9.3.3 UDP Client Operation ............................................................................................................. 36
9.3.4 UDP Server Operation ............................................................................................................ 37
9.3.5 DNS Host Name Resolution ................................................................................................... 38
9.4 Example Code ................................................................................................................................. 39
9.4.1 TCP Client Example Code ...................................................................................................... 39
9.4.2 TCP Server Example Code .................................................................................................... 40
9.4.3 UDP Client Example Code ..................................................................................................... 42
9.4.4 UDP Server Example Code .................................................................................................... 43
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10 Transport Layer Security (TLS) ......................................................................... 45
10.1 TLS Connection Establishment ....................................................................................................... 45
10.2 Server Certificate Installation ........................................................................................................... 46
10.2.1 Technical Background ............................................................................................................ 46
10.2.1.1 Public Key Infrastructure......................................................................................... 46
10.2.1.2 TLS Server Authentication ...................................................................................... 46
10.2.2 Adding a Certificate to the ATWINC Trusted Root Certificate Store ....................................... 46
10.3 ATWINC TLS Limitations ................................................................................................................. 46
10.3.1 Modes of Operation ................................................................................................................ 46
10.3.2 Concurrent Connections ......................................................................................................... 46
10.3.3 Supported Cipher Suites......................................................................................................... 46
10.3.4 Supported Hash Algorithms .................................................................................................... 46
10.4 SSL Client Code Example ............................................................................................................... 47
11 Wi-Fi AP Mode .................................................................................................... 49
11.1
11.2
11.3
11.4
11.5
Overview ......................................................................................................................................... 49
Setting ATWINC AP Mode .............................................................................................................. 49
Limitations ....................................................................................................................................... 49
Sequence Diagram .......................................................................................................................... 49
AP Mode Code Example ................................................................................................................. 50
12 Provisioning........................................................................................................ 51
12.1 BLE Provisioning ............................................................................................................................. 51
12.1.1 BLE Provisioning Code Example ............................................................................................ 53
12.2 HTTP Provisioning........................................................................................................................... 54
12.2.1 Introduction ............................................................................................................................. 54
12.2.2 Limitations .............................................................................................................................. 54
12.2.3 Basic Approach ...................................................................................................................... 54
12.2.4 Provisioning Control Flow ....................................................................................................... 55
12.2.5 HTTP Redirect Feature........................................................................................................... 56
12.2.6 HTTP Provisioning Code Example ......................................................................................... 56
12.3 Wi-Fi Protected Setup (WPS) .......................................................................................................... 57
12.3.1 WPS Configuration Methods .................................................................................................. 57
12.3.2 WPS Limitations ..................................................................................................................... 57
12.3.3 WPS Control Flow .................................................................................................................. 58
12.3.4 WPS Code Example ............................................................................................................... 59
13 Multicast Sockets ............................................................................................... 60
13.1 Overview ......................................................................................................................................... 60
13.2 How to use Filters ............................................................................................................................ 60
13.3 Multicast Socket Code Example ...................................................................................................... 60
14 ATWINC Serial Flash Memory ........................................................................... 65
14.1
14.2
14.3
14.4
14.5
Overview and Features ................................................................................................................... 65
Accessing to Serial Flash ................................................................................................................ 65
Read/Write/Erase Operations .......................................................................................................... 65
Serial (SPI) Flash Map .................................................................................................................... 66
Flash Read, Erase, Write Code Example ........................................................................................ 66
15 Writing a Simple Networking Application ......................................................... 68
15.1 Prerequisites.................................................................................................................................... 68
15.2 Solution Overview............................................................................................................................ 68
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15.3
15.4
15.5
15.6
Project Creation ............................................................................................................................... 69
Wi-Fi Software API Files .................................................................................................................. 69
Reading Temperature Sensor and Controlling LED Status ............................................................. 71
Step By Step Development ............................................................................................................. 72
16 Host Interface Protocol ...................................................................................... 90
16.1 Transfer Sequence Between HIF Layer and ATWINC Firmware ..................................................... 91
16.1.1 Frame Transmit ...................................................................................................................... 91
16.1.2 Frame Receive ....................................................................................................................... 92
16.2 HIF Message Header Structure ....................................................................................................... 93
16.3 HIF Layer APIs ................................................................................................................................ 93
16.4 Scan Code Example ........................................................................................................................ 94
17 ATWINC SPI Protocol ....................................................................................... 100
17.1 Introduction .................................................................................................................................... 100
17.1.1 Command Format ................................................................................................................. 101
17.1.2 Response Format ................................................................................................................. 105
17.1.3 Data Packet Format .............................................................................................................. 106
17.1.4 Error Recovery Mechanism .................................................................................................. 107
17.1.5 Clockless Registers Access.................................................................................................. 108
17.2 Message Flow for Basic Transactions ........................................................................................... 109
17.2.1 Read Single Word ................................................................................................................ 109
17.2.2 Read Internal Register (for clockless registers) .................................................................... 109
17.2.3 Read Block ........................................................................................................................... 110
17.2.4 Write Single Word ................................................................................................................. 111
17.2.5 Write Internal Register (for clockless registers) .................................................................... 111
17.2.6 Write Block ........................................................................................................................... 112
17.3 SPI Level Protocol Example .......................................................................................................... 112
17.3.1 TX (Send Request) ............................................................................................................... 113
17.3.2 RX (Receive Response) ....................................................................................................... 124
Appendix A.
How to Generate Certificates.................................................... 139
A.1 Introduction .................................................................................................................................... 139
A.2 Steps ............................................................................................................................................. 139
Appendix B.
X.509 Certificate Format and Conversion ................................ 140
B.1 Introduction .................................................................................................................................... 140
B.2 Conversion Between Different Formats ......................................................................................... 140
B.2.1 Using Windows ..................................................................................................................... 140
B.2.2 Using OpenSSL .................................................................................................................... 140
B.2.3 Online Conversion ................................................................................................................ 140
Appendix C.
How to Download the Certificate into the ATWINC ................. 141
C.1 Overview ....................................................................................................................................... 141
C.2 Certificate Downloading ................................................................................................................. 141
C.3 Adding New Certificate .................................................................................................................. 141
Appendix D.
Firmware Image Downloader .................................................... 142
D.1 Preparing Environment .................................................................................................................. 142
D.2 Download Firmware ....................................................................................................................... 143
Appendix E.
Gain Settings Builder ................................................................ 145
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E.1 Introduction .................................................................................................................................... 145
E.2 Preparing Environment .................................................................................................................. 145
E.3 How to use..................................................................................................................................... 145
E.3.1 Method 1............................................................................................................................... 145
E.3.2 Method 2............................................................................................................................... 145
Appendix F.
6
Revision History ........................................................................ 147
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Icon Key Identifiers
Delivers contextual information about a specific topic.
Highlights useful tips and techniques.
Highlights objectives to be completed.
Highlights the expected result of an assignment step.
Indicates important information.
2
3
Glossary
BSD
Berkeley Software Distribution
BSP
Board Support Package
HIF
Host Interface Layer
IoT
Internet of Things
OTA
Over The Air
OTP
One Time Programmable
TLS
Transport Layer Security
WINC
Wi-Fi Network Controller
References
[R01]
Atmel-42640-Getting-Started-Guide-for-ATWINC3400WiFi-using-SAMD21-Xplained-Pro_UserGuide.
[R02]
Atmel-42639-Software-Programming-Guide-for-ATWINC3400-WiFi-using-SAMD21-XplainedPro_UserGuide.
[R03]
Atmel-42535-ATWINC3400-MR210-IEEE80211bgn-Link-Ctlr-with-Integrated-Low-EnergyBluetooth40_Datasheet
[R04]
Atmel-42683-ATWINC3400-BLE-WiFi-Scan-and-Connect-Services-Guide_UserGuide
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4
Host Driver Architecture
Figure 4-1.
Host Driver Software Architecture
HOST MCU
IoT Application
HOST Driver Software
WLAN Application Interface API
BSD Socket API
Host Interface (HIF)
BSP
Bus Interface (SPI/I2C/UART)
ATWINC host driver software is a C library which provides the host MCU application with necessary APIs to
perform necessary WLAN, BLE, and socket operations. Figure 4-1 shows the architecture of the ATWINC host
driver software which runs on the host MCU. The components of the host driver are described in the following
sub-sections.
4.1
WLAN API
This module provides an interface to the application for all Wi-Fi operations and any non-IP related operations.
This includes the following services:

Wi-Fi STA management operations
–
Wi-Fi Scan
–
Wi-Fi Connection management (Connect, Disconnect, Connection status, etc.)
–
WPS activation/deactivation

Wi-Fi AP enable/disable

Wi-Fi power save control API
This interface is defined in the file: m2m_wifi.h.
4.2
Socket API
This module provides the socket communication APIs that are mostly compliant with the well-known BSD
sockets to enable rapid application development. To comply with the nature of MCU application environment,
there are differences in API prototypes and in usage of some APIs between ATWINC sockets and BSD
sockets. Please refer to the C in this document (the API reference manual) along with the provided socket code
examples will guide you to understand similarities and differences between ATWINC and BSD sockets.
This interface is defined in the file: socket.h.
The detailed description of the socket operations is provided in Chapter 9: ATWINC Socket Programming.
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4.3
Host Interface (HIF)
The Host Interface is responsible for handling the communication between the host driver and the WINC
firmware. This includes interrupt handling, DMA, and HIF command/response management. The host driver
communicates with the firmware in a form of commands and responses formatted by the HIF layer.
The interface is defined in the file: m2m_hif.h.
The detailed description of the HIF design is provided in Chapter 16: Host Interface Protocol.
4.4
Board Support Package (BSP)
The Board Support Package abstracts the functionality of a specific host MCU platform. This allows the driver
to be portable to a wide range of hardware and hosts. Abstraction includes: pin assignment, power on/off
sequence, reset sequence and peripheral definitions (push buttons, LEDs, etc.).
The minimum required BSP functionality is defined in the file: nm_bsp.h.
4.5
Serial Bus Interface
The Serial Bus Interface module abstracts the hardware associated with implementing the bus between the
Host and the WINC. The serial bus interface abstracts I 2C, SPI, or UART bus interface. The basic bus access
operations (Read and Write) are implemented in this module as appropriate for the interface type and the
specific hardware.
The bus interface APIs are defined in the file: nm_bus_wrapper.h.
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5
WINC System Architecture
Figure 5-1 shows the WINC system architecture. The Soc contains two 32-bit CPUs: an APS3S-Cortus for WiFi and an APS3-Cortus for BLE. In addition it has separate built-in Wi-Fi IEEE-802.11 and BLE 4.0 physical
layers sharing a single final RF front end. The firmware for Wi-Fi comprises the Wi-Fi IEEE-802.11 MAC layer
and embedded protocol stacks which offload the host MCU. The firmware for BLE implements the entrie BLE
stack and privides an application supporting a profile defined for device provisioning. The components of the
system are described in the following sub-sections.
Figure 5-1.
WINC System Architecture
WINC3400 SOC
BUS Interface
SPI FLASH
SPI Master/Slave
I2C
APS3S-Cortus
WINC Host Interface
WINC IoT Library
DNS
Resolver
Radio
Coexistence
SNTP
BLE cross
comms
SSL
Manager
Transport
Layer Security
(TLS)
Wi-Fi
Protected
Setup (WPS)
WINC TCP/IP Stack
Memory
Manager
IEEE 802.11 MAC
Power
Management
Shared PKT
Memory
Program
Memory
Data
Memory
Shared PKT
Memory
Program
Memory
Data
Memory
Shared Radio
Bluetooth V4.1 MAC HW
Bluetooth V4.1 PHY
Corus - Cortus
IEEE 802.11 MAC HW
IEEE 802.11 PHY
Crypto Library
WINC RTOS
DHCP
Client/
Server
APS3-Cortus
Bluetooth V4.1 MAC
Power
Management
Memory
Manager
WINC BLE Library
Radio
Coexistence
5.1
Wi-Fi cross
comms
AT Bluetooth SmartConnect
Stack: SAP, SMT, ATT, GATT,
L2CAP
Provisioning
App support
Bus Interface
Hardware logic for the supported bus types for WINC communications.
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5.2
Non-volatile Storage
The SoC has an integrated 8Mb serial flash inside the WINC package (SIP). This stores both the WINC Wi-Fi
firmware image and the BLE firmware image. It also stores information used by WINC firmware in the run-time.
The detailed description of the serial flash is provided in Chapter 14: ATWINC Serial Flash Memory.
5.3
CPUs
The SoC contains two 32-bit CPUs:
5.4

An APS3S-Cortus 32-bit CPU running at 40MHz clock speed, which executes the embedded WINC WiFi firmware

An APS3-Cortus 32-bit CPU running at 26MHz clock speed, which executes the embedded WINC BLE
firmware
IEEE 802.11 MAC Hardware
The SoC contains a hardware accelerator to ensure fast and compliant implementation of the IEEE 802.11
MAC layer and associated timing. It offloads IEEE 802.11 MAC functionality from firmware to improve
performance and boost the MAC throughput. The accelerator includes hardware encryption/decryption of Wi-Fi
traffic and traffic filtering mechanisms to avoid unnecessary processing in software.
5.5
Bluetooth BLE V4.0 MAC Hardware
The BLE Medium Access Controller (MAC) encodes and decodes HCI packets, constructs baseband data
packages, schedules frames and manages and monitors connection status, slot usage, data flow, routing,
segmentation, and buffer control.
The core performs Link Control Layer management supporting the main BLE states, including advertising and
connection.
5.6
Program Memory
128KB Instruction RAM is provided for execution of the WINC Wi-Fi firmware code.
292KB Instruction RAM is provided for execution of the WINC BLE firmware code.
5.7
Data Memory
64KB Data RAM is provided for WINC Wi-Fi firmware data storage.
64KB Data RAM is provided for WINC BLE firmware data storage.
5.8
Shared Packet Memory
128KB memory is provided for Wi-Fi TX/RX packet management. It is shared between the Wi-Fi MAC
hardware and the CPU. This memory is managed by the Wi-Fi Memory Manager SW component.
32KB memory is provided for BLE TX/RX packet management. It is shared between the BLE MAC hardware
and the CPU. This memory is managed by the BLE Memory Manager SW component.
5.9
IEEE 802.11 MAC Firmware
The system supports IEEE 802.11 b/g/n Wi-Fi MAC including WEP and WPA/WPA2 security supplicant.
Between the MAC hardware and firmware, a full range of IEEE 802.11 features are implemented and
supported including beacon generation and reception, control packet generation and reception and packet
aggregation and de-aggregation.
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5.10
Bluetooth V2.1 MAC Firmware
The BLE subsystem implements all the critical real-time functions required for full compliance with Specification
of the Bluetooth System, v4.1, Bluetooth SIG. The firmware implements an integrated Bluetooth Low Energy
stack which is Bluetooth V4.1 compliant. The firmware supports access to the GAP, SMP, ATT, GATT client /
server and L2CAP service layer protocols. In the ATWINC3400 these services are used by a built-in
application for WI-Fi provisioning.
5.11
Memory Managers
The memory managers on both the Wi-Fi and BLE sides are responsible for the allocation and de-allocation of
memory chunks in both shared packet memory and data memory.
5.12
Power Managements
The Power Management modules on both the Wi-Fi and BLE sides are responsible for handling different power
saving modes supported by the ATWINC and coordinating these modes with the Wi-Fi and BLE transceiver.
5.13
ATWINC RTOS
The firmware includes a low-footprint real-time scheduler which allows concurrent multi-tasking on ATWINC
Wi-Fi CPU. The ATWINC RTOS provides semaphores and timer functionality.
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5.14
ATWINC IoT Library
The ATWINC IoT library provides a set of networking protocols in ATWINC firmware. It offloads the host MCU
from networking and transport layer protocols. The following sections describe the components of ATWINC IoT
library.

ATWINC TCP/IP STACK
The ATWINC TCP/IP is an IPv4.0 stack based on the µIP TCP/IP stack (pronounced micro-IP).
µIP is a low footprint TCP/IP stack which has the ability to run on a memory-constrained microcontroller
platform. It was originally developed by Adam Dunkels, licensed under a BSD style license, and further
developed by a wide group of developers. The ATWINC TCP/IP stack adds to the original µIP
implementation several enhancements to boost TCP and UDP throughput.

DHCP CLIENT/SERVER
A DHCP client is embedded in ATWINC firmware that can obtain an IP configuration automatically after
connecting to a Wi-Fi network.
ATWINC firmware provides an instance of a DHCP server that starts automatically when ATWINC AP
mode is enabled. When the host MCU application activates the AP mode, it is allowed to configure the
DHCP Server IP address pool range within the AP configuration parameters.

DNS RESOLVER
ATWINC firmware contains an instance of an embedded DNS resolver. This module can return an IP
address by resolving the host domain names supplied with the socket API call gethostbyname.

SNTP
The SNTP (Simple Network Time Protocol) module implements an SNTP client used to synchronize the
ATWINC internal clock to the UTC clock.

TRANSPORT LAYER SECURITY
For TLS implementation, see Chapter 10: Transport Layer Security (TLS) for details.

WI-FI PROTECTED SETUP
For WPS protocol implementation, see Section 12.3: Wi-Fi Protected Setup (WPS) for details.

CRYPTO LIBRARY
The Crypto Library contains a set of cryptographic algorithms used by common security protocols. This
library has an implementation of the following algorithms:

MD4 Hash algorithm (used only for MsChapv2.0 digest calculation)

MD5 Hash algorithm

SHA-1 Hash algorithm

SHA-256 Hash algorithm

DES Encryption (used only for MsChapv2.0 digest calculation)

MS-CHAPv2.0 (used as the EAP-TTLS inner authentication algorithm)

AES-128, AES-256 Encryption (used for securing WPS and TLS traffic)

BigInt module for large integer arithmetic (for Public Key Cryptographic computations)

RSA Public Key cryptography algorithms (includes RSA Signature and RSA Encryption algorithms)
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ATWINC Initialization and Simple Application
After powering up the ATWINC device, a set of synchronous initialization sequences must be executed for the
correct operation of the Wi-Fi functions and BLE functions. This chapter aims to explain the different steps
required during the initialization phase of the system. The host MCU does not communicate directly with the
BLE function but controls it through messages to the Wi-Fi MCU. This allows a single interface and driver to be
used to communicate to the ATWINC device.
After initialization, the host MCU application is required to call the ATWINC driver entry point to handle events
from ATWINC firmware.

BSP Initialization

ATWINC Host Driver Initialization

Socket Layer Initialization

Call ATWINC driver entry point
Failure to complete any of the initialization steps will result in failure in ATWINC startup.
6.1
BSP Initialization
The BSP is initialized by calling the nm_bsp_init API. The BSP initialization routine performs the following
steps:

Resets the ATWINC1 using corresponding host MCU control GPIOs

Initializes the host MCU GPIO which connects to ATWINC interrupt line. It configures the GPIO as an
interrupt source to the host MCU. During runtime, ATWINC interrupts the host to notify the application of
events and data pending inside ATWINC firmware.
Initializes the host MCU delay function used within nm_bsp_sleep implementation

6.2
ATWINC Host Driver Initialization
The ATWINC host driver is initialized by calling the m2m_wifi_init API. The Host driver initialization routine
performs the following steps:

Initializes the bus wrapper, I2C, SPI, or UART, depending on the host driver software bus interface
configuration compilation flag USE_I2C, USE_SPI or USE_UART respectively

Registers an application-defined Wi-Fi event handler

Initializes the driver and ensures that the current ATWINC firmware matches the current driver version

Initializes the host interface and the Wi-Fi layer and registers the BSP Interrupt
A Wi-Fi event handler is required for the correct operation of any ATWINC application.
6.3
Socket Layer Initialization
Socket layer initialization is carried out by calling the socketInit API. It must be called prior to any socket
activity. Refer to Section 9.2.1 for more information about socket initialization and programming.
6.4
ATWINC Event Handling
The ATWINC host driver API allows the host MCU application to interact with the ATWINC firmware. To
facilitate interaction, the ATWINC driver implements the Host Interface (HIF) Protocol described in Chapter 16:
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Host Interface Protocol. The HIF protocol defines how to serialize and de-serializes API requests and response
callbacks over the serial bus interface: I2C, UART, or SPI.
Figure 6-1.
ATWINC System Architecture
HOST MCU
Host MCU Application
WINC Host Driver
Host Interface Protocol
WINC
WINC Firmware
WINC Hardware
ATWINC host driver API provides services to the host MCU applications that are mainly divided in two major
categories: Wi-Fi control services and Socket services. The Wi-Fi control services allow actions such as
channel scanning, network identification, connection, and disconnection. The Socket control services allow
application data transfer once a Wi-Fi connection has been established.
6.4.1
Asynchronous Events
Some ATWINC host driver APIs are synchronous function calls, where the result is ready by the return of the
function. However, most ATWINC host driver API functions are asynchronous. This means that when the
application calls an API to request a service, the call is non-blocking and returns immediately, most often
before the requested action is completed. When completed, a notification is provided in the form of a HIF
protocol message from the ATWINC firmware to the host which, in turn, is delivered to the application via a
callback2 function. Asynchronous operation is essential when the requested service such as Wi-Fi connection
may take significant time to complete. In general, the ATWINC firmware uses asynchronous events to signal
the host driver about status change or pending data.
The HIF uses “push” architecture, where data and events are pushed from ATWINC firmware to the host MCU
in FCFS manner. For instance, suppose that host MCU application has two open sockets; socket 1 and socket
2. If ATWINC receives socket 1 data followed by socket 2 data, then HIF shall deliver socket data in two HIF
protocol messages in the order they were received. HIF does not allow reading socket 2 data before socket 1
data.
6.4.2
Interrupt Handling
The HIF interrupts the host MCU when one or more events are pending in ATWINC firmware. The host MCU
application is a big state machine which processes received data and events when ATWINC driver calls the
event callback function(s). In order to receive event callbacks, the host MCU application is required to call the
2
The callback is C function, which contains an application-defined logic. The callback is registered using the ATWINC host
driver registration API to handle the result of the requested service.
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m2m_wifi_handle_events API to let the host driver retrieve and process the pending events from the
ATWINC firmware. It is recommended to call this function either:

Host MCU application polls the API in main loop or a dedicated task

Or at least once when host MCU receives an interrupt from ATWINC firmware
All the application-defined event callback functions registered with ATWINC driver run
in the context m2m_wifi_handle_events API.
The above HIF architecture allows the ATWINC host driver to be flexible to run in the following configurations:


Host MCU with no operating system configuration: In this configuration, the MCU main loop is
responsible to handle deferred work from interrupt handler.
Host MCU with operating system configuration: In this configuration, a dedicated task or thread is
required to call m2m_wifi_handle_events to handle deferred work from interrupt handler.
Host driver entry point m2m_wifi_handle_events is non-reentrant. In the operating
system configuration, it is required to protect the host driver from reentrance by a synchronization object.
When host MCU is polling m2m_wifi_handle_events, the API checks for pending unhandled interrupt from ATWINC. If no interrupt is pending, it returns immediately. If an
interrupt is pending, m2m_wifi_handle_events reads all the pending HIF messages
sequentially and dispatches the HIF message content to the respective registered
callback. If a callback is not registered to handle the type of message, the HIF message content is discarded.
6.5
Code Example
The code example below shows the initialization flow as described in previous sections.
static void wifi_cb(uint8_t u8MsgType, void *pvMsg)
{
}
int main (void)
{
tstrWifiInitParam param;
nm_bsp_init();
m2m_memset((uint8*)&param, 0, sizeof(param));
param.pfAppWifiCb = wifi_cb;
/*intilize the WINC Driver*/
ret = m2m_wifi_init(&param);
if (M2M_SUCCESS != ret){
M2M_ERR("Driver Init Failed <%d>\n",ret);
while(1);
}
while(1){
/* Handle the app state machine plus the WINC event handler */
while(m2m_wifi_handle_events(NULL) != M2M_SUCCESS) {
}
}
}
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ATWINC Configuration
ATWINC firmware has a set of configurable parameters that control its behavior. There is a set of APIs
provided to host MCU application to configure these parameters. The configuration APIs are categorized
according to their functionality into: device, network, and power saving parameters.
Any parameters left unset by the host MCU application shall use their default values assigned during the
initialization of the ATWINC firmware. A host MCU application needs to configure its parameters when coming
out of cold boot or when a specific configuration change is required.
7.1
Device Parameters
7.1.1
System Time
It is important to set the ATWINC system to UTC time to ensure proper validity check of the X509 certificate
expiration date. Since ATWINC does not contain a built-in real-time clock (RTC), there are two ways to obtain
UTC time:
7.1.2

Using the internal SNTP client: Which is enabled by default in the ATWINC firmware at start-up. The
SNTP client synchronizes the ATWINC system clock to the UTC time from well-known time servers, e.g.
"time-c.nist.gov". The SNTP client uses a default update cycle of one day.

From host MCU RTC: If the host MCU has an RTC, the application may disable the SNTP client by
calling m2m_wifi_disable_sntp after ATWINC initialization. The application shall provision the ATWINC
system time by calling m2m_wifi_set_system_time API.
Firmware and HIF Version
During startup, the host driver requests the firmware version through m2m_wifi_get_firmware_version API
which returns the structure tstrM2mRev containing the version number and host interface (HIF) level of the
current ATWINC firmware.
If the HIF level of the current driver is not equal to the HIF level of the current ATWINC
firmware, the driver initialization will fail.
The version parameters provided are:
7.2

M2M_HIF_LEVEL:
Host Interface Level for driver/firmware compatibility

M2M_FIRMWARE_VERSION_MAJOR_NO:
Firmware Major release version number

M2M_FIRMWARE_VERSION_MINOR_NO:
Firmware Minor release version number

M2M_FIRMWARE_VERSION_PATCH_NO:
Firmware Patch release version number
ATWINC Modes of Operation
The ATWINC firmware supports the following modes of operation:

Idle Mode

Wi-Fi STA Mode

Wi-Fi Hotspot (AP)
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Figure 7-1.
ATWINC Modes of Operation
STA
AP
IDLE
7.2.1
Idle Mode
After the host MCU application calls the ATWINC driver initialization m2m_wifi_init API, ATWINC remains in
idle mode waiting for any command to change the mode or to update the configuration parameters. In this
mode ATWINC will enter the power save mode in which it disables the IEEE 802.11 radio and all unneeded
peripherals and suspends the ATWINC CPU. If ATWINC receives any configuration commands from the host
MCU, ATWINC will update the configuration, send back the response to the host MCU, and then go back the
power save mode.
7.2.2
Wi-Fi Station Mode
ATWINC enters station (STA) mode when the host MCU requests connection to an AP using the
m2m_wifi_connect or m2m_wifi_default_connect APIs. ATWINC exits STA mode when it receives a
disconnect request from the Wi-Fi AP conveyed to the host MCU application via the event callback
M2M_WIFI_RESP_CON_STATE_CHANGED or when the host MCU application decides to terminate the connection
via m2m_wifi_disconnect API. ATWINC firmware ignores mode change requests while in this mode until
ATWINC exits the mode.
The supported API functions in this mode use the HIF command types: tenuM2mConfigCmd and tenuM2mStaCmd. See the full list of commands in the header file
m2m_types.h.
For more information about this mode, refer to Chapter 8: Wi-Fi Station Mode.
7.2.3
Wi-Fi Hotspot (AP) Mode
In AP mode, ATWINC allows Wi-Fi stations to connect to ATWINC and obtain IP address from ATWINC DHCP
server. To enter AP mode, host MCU application calls m2m_wifi_enable_ap API. To exit AP mode, the
application calls m2m_wifi_disable_ap API. ATWINC firmware ignores mode change requests while in this
mode until ATWINC exits the mode.
The supported API functions in this mode use the HIF command types:
tenuM2mApCmd and tenuM2mConfigCmd. See the full list of commands in the
header file m2m_types.h.
For more information about this mode, refer to Chapter 11: Wi-Fi AP Mode.
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7.3
Network Parameters
7.3.1
Wi-Fi MAC Address
The ATWINC firmware provides two methods to assign the ATWINC MAC address:

Assignment from host MCU: When host MCU application calls the m2m_wifi_set_mac_address API
after initialization using m2m_wifi_init API.

Assignment from ATWINC OTP (One Time Programmable) memory: ATWINC supports an internal
MAC address assignment method through a built-in OTP memory. If MAC address is programmed in the
ATWINC OTP memory, the ATWINC working MAC address defaults to the OTP MAC address unless
the host MCU application sets a different MAC address programmatically after initialization using the API
m2m_wifi_set_mac_address.
OTP MAC address is programmed in ATWINC OTP memory at manufacturing time.
For more details, refer to description of the following APIs in the WINC3400_IoT_SW_APIs.chm that was
supplied in the WINC3400_IoT_REL software package.

m2m_wifi_get_otp_mac_address

m2m_wifi_set_mac_address

m2m_wifi_get_mac_address
Use m2m_wifi_get_otp_mac_address API to check if there is a valid programmed
MAC address in ATWINC OTP memory. The host MCU application can also use the
same API to read the OTP MAC address octets. The m2m_wifi_get_otp_mac_address
API must not be confused with the m2m_wifi_get_mac_address API, which reads the
working ATWINC MAC address in ATWINC firmware regardless from whether it is assigned from the host MCU or from ATWINC OTP.
7.3.2
IP Address
ATWINC firmware uses the embedded DHCP client to obtain an IP configuration automatically after a
successful Wi-Fi connection. After the IP configuration is obtained, the host MCU application is notified by the
asynchronous event M2M_WIFI_RESP_IP_CONFIGURED.
Alternatively, the host MCU application can set a static IP configuration by calling the
m2m_wifi_set_static_ip API. Setting a static IP address will cancel any pending DHCP requests and
disable the DHCP client until the next Wi-Fi connection attempt to the same AP or any other AP.
7.4
Power Saving Parameters
When a Wi-Fi station is idle, it disables the Wi-Fi radio and enters power saving mode. The AP is required to
buffer data while stations are in power save mode and transmit data later when stations wake up. The AP
transmits a beacon frame periodically to synchronize the network every beacon period. A station which is in
power save wakes up periodically to receive the beacon and monitor the signaling information included in the
beacon. The beacon conveys information to the station about unicast data, which belong to the station and
currently buffered inside the AP while the station was sleeping. The beacon also provides information to the
station when the AP is going to send broadcast/multicast data.
7.4.1
Power Saving Modes
ATWINC firmware supports multiple power saving modes which provide flexibility to the host MCU application
to tweak the system power consumption. The host MCU can configure the ATWINC power saving policy using
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the m2m_wifi_set_sleep_mode and m2m_wifi_set_lsn_int APIs. ATWINC supports the following power
saving modes:

M2M_PS_MANUAL

M2M_PS_AUTOMATIC

M2M_PS_H_AUTOMATIC

M2M_PS_DEEP_AUTOMATIC
M2M_PS_DEEP_AUTOMATIC mode recommended for most applications.
7.4.1.1 M2M_PS_MANUAL
This is a fully host-driven power saving mode.

ATWINC sleeps when the host instructs it to do so using the m2m_wifi_request_sleep API. During
ATWINC sleep, the host MCU can decide to sleep also for extended durations.

ATWINC wakes up when the host MCU application requests services from ATWINC by calling any host
driver API function, e.g. Wi-Fi or socket operation
In M2M_PS_MANUAL mode, when ATWINC sleeps due to m2m_wifi_request_sleep
API. ATWINC does not wake up to receive and monitor AP beacon. Beacon monitoring is resumed when host MCU application wakes up the ATWINC.
For an active Wi-Fi connection, the AP may decide to drop the connection if ATWINC is absent because it
sleeps for long time duration. If connection is dropped, ATWINC detects the disconnection on the next wake-up
cycle and notifies the host to reconnect to the AP again. In order to maintain an active Wi-Fi connection for
extended durations, the host MCU application should wake up the ATWINC periodically so that ATWINC can
send a keep-alive Wi-Fi frame to the AP. The host should choose the sleep period carefully to satisfy the
tradeoff between keeping the Wi-Fi connection uninterrupted and minimizing the system power consumption.
This mode is useful for applications which send notifications very rarely due to a certain trigger. It fits also
applications which send notifications periodically with a very long spacing between notifications. Careful power
planning is required when using this mode. If the host MCU decides to sleep for very long period, it may use
M2M_PS_MANUAL or may power off ATWINC3 completely. The advantage of this mode compared to powering off
ATWINC is that M2M_PS_MANUAL saves the time required for ATWINC firmware to boot since the firmware is
always loaded in ATWINC memory. The real pros and cons depend on the nature of the application. In some
applications, the sleep duration could be long enough to be a power-efficient decision to power off ATWINC
and power it on again and reconnect to the AP when host MCU wakes up. In other situations, a latencysensitive application may choose to use M2M_PS_MANUAL to avoid ATWINC firmware boot latency on the
expense of slightly increased power consumption.
During ATWINC sleep, ATWINC in M2M_PS_MANUAL mode saves more power than M2M_PS_DEEP_AUTOMATIC
mode since in the former mode ATWINC skips beacon monitoring while the latter it wakes up to receive
beacons. The comparison should also include the effect of host MCU sleep duration: If host MCU sleep period
is too long, the Wi-Fi connection may drop frequently and the power advantage of M2M_PS_MANUAL is lost due
to the power consumed in Wi-Fi reconnection. In contrast, M2M_PS_DEEP_AUTOMATIC can keep the Wi-Fi
connection for long durations at the expense of waking up ATWINC to monitor the AP beacon.
3
20
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7.4.1.2 M2M_PS_AUTOMATIC
This mode is deprecated and kept for backward compatibility and development reasons. It should not be used
in new implementations.
7.4.1.3 M2M_PS_H_AUTOMATIC
This mode implements the Wi-Fi standard power saving method in which ATWINC will sleep and wake up
periodically to monitor AP beacons. In contrast to M2M_PS_MANUAL, this mode does not involve the host MCU
application.
In this mode, when ATWINC enters sleep state, it only turns off the IEEE 802.11 radio, MAC, and PHY. All
system clocks and the APS3S-Cortus CPU are on.
This mode is useful for a low-latency packet transmission because ATWINC clocks are on and ready to
transmit packets immediately, unlike the M2M_PS_DEEP_AUTOMATIC which may require time to wake up the
ATWINC to transmit a packet if ATWINC was sleep mode.
M2M_PS_H_AUTOMATIC mode is very similar to M2M_PS_DEEP_AUTOMATIC except that the former power
consumption is higher than the latter the since ATWINC system clock is on.
7.4.1.4 M2M_PS_DEEP_AUTOMATIC
Like M2M_PS_HS_AUTOMATIC, this mode implements the Wi-Fi standard power saving method. However, when
ATWINC enters sleep state, the system clock is turned off.
Before sleep, the ATWINC programs a hardware timer (running on an internal low-power oscillator) with a
sleep period determined by the ATWINC firmware power management module.
While sleeping, the ATWINC will wake up if one of the following events happens:


7.4.2
Expiry of the hardware sleep timer. ATWINC wakes up to receive the upcoming beacon from AP.
ATWINC wakes up4 when the host MCU application requests services from ATWINC by calling any host
driver API function, e.g. Wi-Fi or socket operation
Configuring Listen Interval and DTIM Monitoring
ATWINC allows the host MCU application to tweak the system’s power consumption by configuring beacon
monitoring parameters. The AP sends beacons periodically every beacon period (e.g. 100ms). The beacon
contains a TIM element which informs the station about presence of unicast data for the station buffer in the
AP. The station negotiates with the AP a listen interval which is how many beacon periods the station can
sleep before it wakes up to receive data buffer in AP. The AP beacon also contains the DTIM, which contains
information to the station about the presence of broadcast/multicast data. Which the AP is ready to transmit
following this beacon after normal channel access rules (CSMA/CA).
The ATWINC driver allows the host MCU application to configure beacon monitoring parameters as follows:

Configure DTIM monitoring: I.e. enable or disable reception of broadcast/multicast data using the API:
– m2m_wifi_set_sleep_mode(desired_mode, 1) to receive broadcast data
–

m2m_wifi_set_sleep_mode(desired_mode, 0) to ignore broadcast data
Configure the listen interval: using the m2m_wifi_set_lsn_int API
Listen interval value provided to the m2m_wifi_set_lsn_int API is expressed in the
unit of beacon period.
4
The wakeup sequence is handled internally in the ATWINC host driver in the hif_chip_wake API. Refer to the reference
Chapter 16 for more information.
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Wi-Fi Station Mode
This chapter provides information about ATWINC Wi-Fi station (STA) mode described in Section 7.2.2. Wi-Fi
station mode involves scan operation; association to an AP using parameters (SSID and credentials) provided
by host MCU or using AP parameters stored in ATWINC non-volatile storage (default connection). This chapter
also provides information about supported security modes along with code examples.
8.1
Scan Configuration Parameters
8.1.1
Scan Region
The number of RF channels supported varies by geographical region. For example, 14 channels are supported
in Asia while 11 channels are supported in North America. By default the ATWINC initial region configuration is
equal to 14 channels (Asia), but this can be changed by setting the scan region using the
m2m_wifi_set_scan_region API.
8.1.2
Scan Options
During Wi-Fi scan operation, ATWINC sends probe request Wi-Fi frames and waits for some time on the
current Wi-Fi channel to receive probe response frames from nearby APs before it switches to the next
channel. Increasing the scan wait time has a positive effect on the number of access pointed detected during
scan. However, it has a negative effect on the power consumption and overall scan duration. ATWINC
firmware default scan wait time is optimized to provide the tradeoff between power consumption and scan
accuracy. ATWINC firmware provides flexible configuration options to the host MCU application to increase the
scan time. For more detail, refer to the m2m_wifi_set_scan_options API.
8.2
Wi-Fi Scan
A Wi-Fi scan operation can be initiated by calling the m2m_wifi_request_scan API. The scan can be
performed on all 2.4GHz Wi-Fi channels or on a specific requested channel.
The scan response time depends on the scan options. For instance, if the host MCU application requests to
scan all channels, the scan time will be equal to NoOfChannels (14) * M2M_SCAN_MIN_NUM_SLOTS*
M2M_SCAN_MIN_SLOT_TIME (refer to the WINC3400_IoT_SW_APIs.chm that was supplied in the
WINC3400_IoT_REL software package on how to customize the scan parameters).
The scan operation is illustrated in Figure 8-1.
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Figure 8-1.
Wi-Fi Scan Operation
M2M APPLICATION
M2M HOST DRIVER
m2m_wifi_request_scan(WiFi_Channel_ID)
wifi_cb(M2M_WIFI_RESP_SCAN_DONE,
tstrM2mScanDone* );


Read the number of found APs(N).
Start reading the SCAN result list.
m2m_wifi_req_scan_result(0)
wifi_cb(M2M_WIFI_RESP_SCAN_RESULT,
tstrM2mWifiscanResult* );
Process the Scan
result(*)
m2m_wifi_req_scan_result(N - 1)
8.3
On Demand Wi-Fi Connection
The host MCU application may establish a Wi-Fi connection on demand if all the required connection
parameters (SSID, security credentials, etc.) are known to the application. To start a Wi-Fi connection on
demand, the application shall call the API m2m_wifi_connect.
Using m2m_wifi_connect implies that the host MCU application has prior knowledge of
the connection parameters. For instance, connection parameters can be stored on nonvolatile storage attached to the host MCU.
The Wi-Fi on demand connection operation is described in Figure 8-2.
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Figure 8-2.
On Demand Wi-Fi Connection
M2M APPLICATION
M2M HOST DRIVER
m2m_wifi_connect(Sec_Type, SSID,SSID_Len,
Key,Key_Len ,Channel_ID(*));
wifi_cb(M2M_WIFI_REQ_CON_STATE_CHANGED,
tstrM2mWifiStateChanged* );
wifi_cb(M2M_WIFI_REQ_DHCP_CONF, uint8* );


8.4
Set the IP Address.
Start M2M socket Application.
Default Connection
The host MCU application may establish a Wi-Fi connection without prior knowledge to the AP information by
calling the m2m_wifi_default_connect API.
Default connection relies on the connection profiles provisioned into ATWINC serial flash via the provisioning
method described in Chapter 12: Provisioning. Alternatively, connection profiles are created and stored in
ATWINC serial flash when the host MCU application successfully connects once to an AP using the
m2m_wifi_connect API described in Section 8.3. If there are no cached profiles or if a connection cannot be
established with any of the cached profiles, an event of type M2M_WIFI_RESP_DEFAULT_CONNECT is delivered to
the host driver indicating failure.
Upon successful default connection, the host application can read the current Wi-Fi connection status
information by calling the m2m_wifi_get_connection_info API. The m2m_wifi_get_connection_info is an
asynchronous API. The actual connection information is provided in the asynchronous event
M2M_WIFI_RESP_CONN_INFO in Wi-Fi callback. The callback parameter of type tstrM2MConnInfo provides
information about AP SSID, RSSI (AP received power level), security type, and IP address obtained by DHCP.
A connection profile is cached in the serial flash if and only if the connection is successfully established with the target AP.
The Wi-Fi default connection operation is described in Figure 8-3.
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Figure 8-3.
Wi-Fi Default Connection
M2M APPLICATION
M2M HOST DRIVER
m2m_wifi_default_connect();
wifi_cb(M2M_WIFI_REQ_CON_STATE_CHANGED,
tstrM2mWifiStateChanged* );
wifi_cb(M2M_WIFI_REQ_DHCP_CONF, uint8* );


8.5
Set the IP Address.
Start M2M socket Application.
Wi-Fi Security
The following types of security are supported in ATWINC Wi-Fi STA mode.

M2M_WIFI_SEC_OPEN

M2M_WIFI_SEC_WEP

M2M_WIFI_SEC_WPA_PSK (WPA/WPA2-Personal Security Mode i.e. Passphrase)

M2M_WIFI_SEC_802_1X (WPA-Enterprise security)
The currently supported 802.1x authentication algorithm is EAP-TTLS with MsChapv2.0
authentication.
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8.6
Example Code
#define M2M_802_1X_USR_NAME
#define M2M_802_1X_PWD
#define AUTH_CREDENTIALS
"user_name"
"password"
{M2M_802_1X_USR_NAME, M2M_802_1X_PWD }
int main (void)
{
tstrWifiInitParam param;
tstr1xAuthCredentials gstrCred1x = AUTH_CREDENTIALS;
nm_bsp_init();
m2m_memset((uint8*)&param, 0, sizeof(param));
param.pfAppWifiCb = wifi_event_cb;
/* intilize the WINC Driver
*/
ret = m2m_wifi_init(&param);
if (M2M_SUCCESS != ret)
{
M2M_ERR("Driver Init Failed <%d>\n",ret);
while(1);
}
/* Connect to a WPA-Enterprise AP
*/
m2m_wifi_connect("DEMO_AP", sizeof("DEMO_AP"), M2M_WIFI_SEC_802_1X,
(uint8*)&gstrCred1x, M2M_WIFI_CH_ALL);
while(1)
{
/************************************************************************/
/* Handle the app state machine plus the WINC event handler
*/
/************************************************************************/
while(m2m_wifi_handle_events(NULL) != M2M_SUCCESS)
{
}
}
}
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9
ATWINC Socket Programming
9.1
Overview
The ATWINC socket application programming interface (API) provides a method that allows host MCU
application to interact with intranet and remote internet hosts. The ATWINC sockets API is based on the BSD
(Berkeley) sockets. This chapter explains the ATWINC socket programming and how it differs from regular
BSD sockets.
This chapter assumes the reader to have a basic understanding of the BSD sockets,
TCP, UDP, and the Internet protocols. Follow the online references provided in link in
the name of each topic for more information.
9.1.1
ATWINC Socket Types
The ATWINC sockets API provides two types of sockets:
9.1.2

Datagram sockets (connection-less sockets) - which use the UDP protocol

Stream sockets (connection oriented sockets) - which use the TCP protocol
Socket Properties
Each ATWINC socket is identified by a unique combination of:

Socket ID: It is a unique identifier for each socket. This is the return value of the "socket" API.

Local socket address: A combination of ATWINC IP address and port number assigned by the
ATWINC firmware for the socket.
Protocol: This is the transport layer protocol, either TCP or UDP.

Note that TCP port 53 and UDP port 53 represent two different sockets.

9.1.3
Remote socket address: Applicable only for TCP stream sockets. This is necessary since TCP is
connection oriented. Each connection is made to a specific IP address and port number requires a
separate socket. The remote socket address can be obtained in the socket event callback as discussed
later.
Limitations

The ATWINC sockets API support a maximum of seven TCP sockets and 4 for UDP sockets

The ATWINC sockets API support only IPv4. It does not support IPv6.
9.2
ATWINC Sockets API
9.2.1
API Prerequisites

The C header file “socket.h”: Includes all the necessary socket API function declarations. When using
any ATWINC sockets API described in the following sections, the host MCU application should to include
the socket.h header file.

Initialization: The ATWINC socket API shall be initialized once before calling any sockets API function.
This is done by using the "socketInit" API described in the Section 9.2.3.
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9.2.2
Non-blocking Asynchronous Socket APIs
Most ATWINC socket APIs are asynchronous function calls that do not block the host MCU application. The
behavior of ATWINC asynchronous APIs is described in Section 6.4.1.
For example, the host MCU application can register an application-defined socket event callback function using
the ATWINC socket API registerSocketCallback. When the host MCU application calls the socket API
connect, the API returns a zero value (SUCCESS) immediately indicating that the request is accepted. The host
MCU application must then wait for the ATWINC socket API to call the registered socket callback when the
connection is established or if there was a connection timeout. The socket callback function provides the
necessary information to determine if the connection was successful or not.
9.2.3
Socket API Functions
ATWINC sockets API provide the following functions (see the subsections below).
9.2.3.1 socketInit
The host MCU application must call the API socketInit once during initialization. The API is a synchronous
API.
9.2.3.2 registerSocketCallback
The registerSocketCallback function allows the host MCU application to provide the ATWINC sockets with
application-defined event callbacks for socket operations. The API is a synchronous API. The API registers the
following callbacks:

The socket event callback

The DNS resolve callback
The socket event callback is an application-defined function that is called by the ATWINC socket API whenever
a socket event occurs. Within this handler, the host MCU application should provide an application-defined
logic that handles the events of interest.
The DNS resolve event handler is the application-defined function that is called by the ATWINC socket API to
return the results of gethostbyname. By implication, this will only occur after the host MCU application has
called the gethostbyname function. If successful, the callback provides the IP address for the desired domain
name.
9.2.3.3 socket
The socket function creates a new socket of a specified type and returns the corresponding socket ID. The
API is a synchronous API.
The socket ID is required by most other socket functions and is also passed as an argument to the socket
event callback function to identify which socket generated the event.
9.2.3.4 connect
The connect function is used with TCP sockets to establish a new connection to a TCP server.
The connect function will result in a SOCKET_MSG_CONNECT sent to the socket event handler callback upon
completion. The connect event will be sent when the TCP server accepts the connection or, if no remote host
response is received, after a timeout interval of approximately 30 seconds.
The SOCKET_MSG_CONNECT event callback provides a tstrSocketConnectMsg containing an error code. The error code is 0 if the connection was successful or a negative
value to indicate an error due to a timeout condition or if connect is used with UDP
socket.
Figure 9-1 shows the ATWINC socket API connect to remote server host.
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Figure 9-1.
TCP Client API Call Sequence
9.2.3.5 bind
The bind function can be used for server operation for both UDP and TCP sockets. Its purpose is to associate
a socket with an address structure (port number and IP address).
The bind function call will result a SOCKET_MSG_BIND event sent to the socket callback handler with the bind
status. Calls to listen, send, sendto, recv, and recvfrom functions should not be issued until the bind
callback is received.
9.2.3.6 listen
The listen function is used for server operations with TCP stream sockets. After calling the listen API the
socket will accept a connection request from a remote host. The listen function causes a
SOCKET_MSG_LISTEN event notification to be sent to the host after the socket port is ready to indicate listen
operation success or failure.
When a remote peer establishes a connection, a SOCKET_MSG_ACCEPT event notification is sent to the
application.
9.2.3.7 accept
The accept function is deprecated and calling this API has no effect. It is kept only for backward compatibility.
The listen API will implicitly accepts accept connections from a TCP remote peer.
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Figure 9-2.
TCP Server API Call Sequence
Although the accept function is deprecated, the SOCKET_MSG_ACCEPT event occurs whenever a remote host
connects to the ATWINC TCP server. The event message will contain the IP address and port number of the
connected remote host.
9.2.3.8 send
The send function is used by the application to send data to a remote host. The send function can be used to
send either UDP or TCP data depending on the type of socket. For a TCP socket a connection must be
established first. For a UDP socket, the target remote host must be specified as part of the address structure
during the bind function.
The send function will generate a SOCKET_MSG_SEND event callback after the data is transmitted to the remote
host. For TCP sockets, this event guarantees that the data has been delivered to the remote host TCP/IP stack
(the remote application must use the recv function to be able to read the data though). For UDP sockets it
means that the data has been transmitted but there are no guarantees that the data has arrived to the remote
host as per UDP protocol nature. The application is responsible to guarantee data delivery in the UDP sockets
case.
The SOCKET_MSG_SEND event callback will return the size of the data transmitted if the transmission in the
success case and zero or negative value in case of an error.
9.2.3.9 sendto
The sendto function is used by the application to send UDP data to a remote host. It can only be used with
UDP sockets. The IP address and port of the destination remote host is included as a parameter to the sendto
function.
The SOCKET_MSG_SENDTO event callback returns the size of the data transmitted in the success case and zero
or negative value in case of an error.
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9.2.3.10 recv / recvfrom
The recv and recvfrom functions are used to read data from TCP and UDP sockets respectively. Their
operation is otherwise identical.
The host MCU application calls the recv or recvfrom function with a pre allocated buffer. When the
SOCKET_MSG_RECV or SOCKET_MSG_RECVFROM event callback arrives this buffer will contain the received data.
The received data size indicates the status:

Positive: Data received.

Zero: Socket connection is terminated.

Negative value: This indicates an error.
In the case of TCP sockets, it is recommended to call the recv function after each successful socket
connection (client or server). Otherwise, received data will be buffered in the ATWINC firmware wasting the
systems resources until the socket is explicitly closed using a close function call.
9.2.3.11 close
The close function is used to release the resources allocated to the socket and, for a TCP stream socket, also
terminate an open connection.
Each call to the socket function should be matched with a call to the close function. In addition, sockets that
have been accepted on a server socket port should also be closed using this function.
9.2.3.12 setsockopt
The setsockopt function may be used to set socket options to control the socket behavior.
The options supported are:


SO_SET_UDP_SEND_CALLBACK: Enables or disables the send /sendto event callbacks. The user might
want to disable the sendto event callback for UDP sockets to enhance the socket connection
throughput.
IP_ADD_MEMBERSHIP: Used to subscribe to IP Multicast addresses.

IP_DROP_MEMBERSHIP: Used to unsubscribe to IP Multicast addresses.
Disabling send/sendto callbacks using setsockopts is recommended in high throughput applications.
9.2.3.13 gethostbyname
The gethostbyname function is used to resolve a host name (e.g. URL) to a host IP address via the Domain
Name System (DNS). This is limited for IPv4 addresses only. Operation depends on having configured a DNS
server IP address and having access to the DNS hierarchy through the internet.
After gethostbyname has been called, a callback to the DNS resolver handler will be made. If the IP address
has been determined it will be returned. If it cannot be determined or if the DNS server is not accessible (30
second timeout) an IP address value of zero will be indicated.
A return IP value of zero indicates an error (e.g. the internet connection is down or DNS
is unavailable) and the host MCU application may try the function call gethostbyname
again later.
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9.2.4
Summary
Table 9-1 summarizes the ATWINC socket API and shows its compatibility with BSD socket APIs:
Table 9-1.
ATWINC Socket API Summary
BSD API
ATWINC API
ATWINC API
Type
Server/
Client
TCP/UDP
socket
socket
Synchronous
Both
both
Creates a new socket
connect
connect
Asynchronous
Client
TCP
Initialize a TCP connection request to a remote server
bind
bind
Asynchronous
Server
both
Binds a socket to an address (address/port)
listen
listen
Asynchronous
Server
TCP
Allow a bound socket to listen to remote connections for its local port
accept
accept
send
send
Asynchronous
Both
Both
Sends packet
sendto
sendto
Asynchronous
Both
UDP
Sends packet over UDP sockets
Depreciated, Implicit accept in listen
write
Not supported
recv
recv
Asynchronous
Both
Both
Receive packet
recvfrom
recvfrom
Asynchronous
Both
Both
Receive packet
read
Not supported
close
close
Synchronous
Both
Both
Terminate TCP connection and release system resources
gethostbyname
gethostbyname
Asynchronous
Both
Both
Get IP address of certain host name
gethostbyaddr
Not supported
select
Not supported
poll
Not supported
setsockopt
setsockopt
Synchronous
Both
Both
getsockopt
32
Brief
Sets socket option
Not supported
htons/ntohs
_htons/_ntohs
Synchronous
Both
Both
Convert a 2-byte integer from the host representation to the Network byte order representation (and vice versa)
htonl/ntohl
_htonl/_ntohl
Synchronous
Both
Both
Convert a 4-byte integer from the host representation to the Network byte order representation (and vice versa)
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9.3
Socket Connection Flow
In the following sub-sections the TCP and UDP (client and server) operations are described in detail.
Figure 9-3.
Typical Socket Connection Flow
socketInit
registerSocketCallback
Socket
bind
socketInit
Bind event
callback
registerSocketCallback
listen
Client Operations
Socket
connect
Listen event
callback
Accept event
callback
Server Operations
recv
send
Send event
callback
Recv event
callback
Data Exchange
send
recv
recv
Recv event
callback
close
End Connection
close
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9.3.1
TCP Client Operation
Figure 9-4 shows the message flow for transferring data with a TCP client.
Figure 9-4.
TCP Client Sequence Diagram
HOST
DRIVER
APPLICATION
WINC
socket(SOCK_STREAM)
clientSocketHdl
connect(clientSocketHdl)
SOCKET_MSG_CONNECT
send(clientSocketHdl, data)
recv(clientSocketHdl)
SOCKET_CMD_CONNECT
SOCKET_CMD_CONNECT
SOCKET_CMD_SEND
TCP(SYN)
TCP(SYN,ACK)
TCP Packet
SOCKET_CMD_RECV
SOCKET_MSG_RECV
SOCKET_CMD_RECV
TCP Packet
Data Exchange (send/recv)
close(clientSocketHdl)
SOCKET_CMD_CLOSE
Notes: 1.
TCP(FIN)
The host application must register a socket notification callback function. The function must be of
type tpfAppSocketCb and must handle socket event notifications appropriately.
2. If the client knows the IP of the server, it may call connect directly as shown in Figure 9-4. If only
the server URL is known, then the application should resolve the server URL first calling the
gethostbyname API.
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9.3.2
TCP Server Operation
Figure 9-5.
TCP Server Sequence Diagram
HOST
DRIVER
APPLICATION
WINC
socket(SOCK_STREAM)
listenSocketHdl
bind(listenSocketHdl,port)
SOCKET_CMD_BIND
SOCKET_CMD_BIND
SOCKET_MSG_BIND
listen(listenSocketHdl)
SOCKET_MSG_LISTEN
SOCKET_CMD_LISTEN
SOCKET_CMD_LISTEN
TCP(SYN)
TCP(SYN,ACK)
SOCKET_MSG_ACCEPT
SOCKET_CMD_ACCEPT
Get the accepted
socket handle è
acceptedSocketHdl
recv(acceptedSocketHdl)
SOCKET_CMD_RECV
TCP Packet
SOCKET_MSG_RECV
send(acceptedSocketHdl, data)
SOCKET_CMD_RECV
SOCKET_CMD_SEND
TCP Packet
Data Exchange (send/recv)
close(acceptedSocketHdl)
close(listenSocketHdl)
Note:
SOCKET_CMD_CLOSE
TCP(FIN)
SOCKET_CMD_CLOSE
The host application must register a socket notification callback function. The function must be of type:
tpfAppSocketCb and must handle socket event notifications appropriately.
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9.3.3
UDP Client Operation
Figure 9-6 shows the message flow for transferring data with a UDP client.
Figure 9-6.
UDP Client Sequence Diagram
HOST
DRIVER
APPLICATION
WINC
socket(SOCK_DGRAM)
clientSocketHdl
sendto(clientSocketHdl,data,addr)
recvfrom(clientSocketHdl)
SOCKET_MSG_RECVFROM
SOCKET_CMD_SENDTO
SOCKET_CMD_RECVFROM
SOCKET_CMD_RECVFROM
UDP Packet
UDP Packet
Data Exchange (send/recv)
close(clientSocketHdl)
SOCKET_CMD_CLOSE
The first send message must be performed with the sendto API with the destination address
specified.
2. If further messages are to be sent to the same address, the send API can be used.
3. recv can be used instead of recvfrom.
Notes: 1.
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9.3.4
UDP Server Operation
Figure 9-7 shows the message flow for transferring data after establishing a UDP server.
Figure 9-7.
UDP Server Sequence Diagram
HOST
DRIVER
APPLICATION
WINC
socket(SOCK_DGRAM)
serverSocketHdl
bind(serverSocketHdl,port)
SOCKET_CMD_BIND
SOCKET_CMD_BIND
SOCKET_MSG_BIND
recvfrom(serverSocketHdl)
SOCKET_CMD_RECVFROM
SOCKET_CMD_RECVFROM
UDP Packet
SOCKET_MSG_RECVFROM
sendto(serverSocketHdl, data)
SOCKET_CMD_SENDTO
UDP Packet
Data Exchange (send/recv)
close(serverSocketHdl)
SOCKET_CMD_CLOSE
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9.3.5
DNS Host Name Resolution
Figure 9-8 shows the message flow for resolving a URL to and IP address.
Figure 9-8.
DNS Resolution Sequence
HOST
DRIVER
APPLICATION
WINC
registerSocketCallback(dnsResolveCB)
gethostbyname(hostName)
SOCKET_CMD_DNS_RESOLVE
DNS_Resolver
formats a DNS
Query with the
given hostName
DNS Query
DNS Answer
DNS_Resolver
Extracts the
hostIP for
hostName from
the DNS Answer
dnsResolveCB(hostName, hostIP)
SOCKET_CMD_DNS_RESOLVE
Notes: 1.
The host application requests to resolve hostname (e.g. www.foobar.com), by calling the function
gethostbyname.
2. Before calling the gethostbyname, the application must register a DNS response callback function
using the function registerSocketCallback.
3. After the ATWINC DNS_Resolver module obtains the IP address (hostIP) corresponding to the
given HostName, the dnsResolveCB will be called with the hostIP.
4. If an error occurs or if the DNS request encounters a timeout, the dnsResolveCB is called with IP
address value zero indicating a failure to resolve the domain name.
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9.4
Example Code
This section provides code samples for different socket applications. For additional socket code example, refer
to [R03] ATWINC3400 Software Programming Guide.
9.4.1
TCP Client Example Code
SOCKET
uint8
clientSocketHdl;
rxBuffer[256];
/* Socket event handler.
*/
void tcpClientSocketEventHandler(SOCKET sock, uint8 u8Msg, void * pvMsg)
{
if(sock == clientSocketHdl)
{
if(u8Msg == SOCKET_MSG_CONNECT)
{
// Connect Event Handler.
tstrSocketConnectMsg *pstrConnect = (tstrSocketConnectMsg*)pvMsg;
if(pstrConnect->s8Error == 0)
{
// Perform data exchange.
uint8 acSendBuffer[256];
uint16 u16MsgSize;
// Fill in the acSendBuffer with some data here
// send data
send(clientSocketHdl, acSendBuffer, u16MsgSize, 0);
// Recv response from server.
recv(clientSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
}
else
{
printf("TCP Connection Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_RECV)
{
tstrSocketRecvMsg *pstrRecvMsg = (tstrSocketRecvMsg*)pvMsg;
if((pstrRecvMsg->pu8Buffer != NULL) && (pstrRecvMsg->s16BufferSize > 0))
{
// Process the received message.
// Close the socket.
close(clientSocketHdl);
}
}
}
}
// This is the DNS callback. The response of gethostbyname is here.
void dnsResolveCallback(uint8* pu8HostName, uint32 u32ServerIP)
{
struct sockaddr_in strAddr;
if(u32ServerIP != 0)
{
clientSocketHdl = socket(AF_INET,SOCK_STREAM,u8Flags);
if(clientSocketHdl >= 0)
{
strAddr.sin_family
= AF_INET;
strAddr.sin_port
= _htons(443);
strAddr.sin_addr.s_addr
= u32ServerIP;
connect(clientSocketHdl, (struct sockaddr*)&strAddr, sizeof(struct sockaddr_in));
}
}
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else
{
printf("DNS Resolution Failed\n");
}
}
/* This function needs to be called from main function. For the callbacks to be invoked correctly, the API
m2m_wifi_handle_events should be called continuously from main. */
void tcpConnect(char *pcServerURL)
{
// Initialize the socket layer.
socketInit();
// Register socket application callbacks.
registerSocketCallback(tcpClientSocketEventHandler, dnsResolveCallback);
// Resolve Server URL.
gethostbyname((uint8*)pcServerURL);
}
9.4.2
TCP Server Example Code
SOCKET
uint8
uint8
listenSocketHdl, acceptedSocketHdl;
rxBuffer[256];
bIsfinished = 0;
/* Socket event handler.
*/
void tcpServerSocketEventHandler(SOCKET sock, uint8 u8Msg, void * pvMsg)
{
if(u8Msg == SOCKET_MSG_BIND)
{
tstrSocketBindMsg *pstrBind = (tstrSocketBindMsg*)pvMsg;
if(pstrBind->status == 0)
{
listen(listenSocketHdl, 0);
}
else
{
printf("Bind Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_LISTEN)
{
tstrSocketListenMsg *pstrListen = (tstrSocketListenMsg*)pvMsg;
if(pstrListen->status != 0)
{
printf("listen Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_ACCEPT)
{
// New Socket is accepted.
tstrSocketAcceptMsg *pstrAccept = (tstrSocketAcceptMsg *)pvMsg;
if(pstrAccept->sock >= 0)
{
// Get the accepted socket.
acceptedSocketHdl = pstrAccept->sock;
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recv(acceptedSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
}
else
{
printf("Accept Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_RECV)
{
tstrSocketRecvMsg
*pstrRecvMsg = (tstrSocketRecvMsg*)pvMsg;
if((pstrRecvMsg->pu8Buffer != NULL) && (pstrRecvMsg->s16BufferSize > 0))
{
// Process the received message
// Perform data exchange
uint8
uint16
acSendBuffer[256];
u16MsgSize;
// Fill in the acSendBuffer with some data here
// Send some data.
send(acceptedSocketHdl, acSendBuffer, u16MsgSize, 0);
// Recv response from client.
recv(acceptedSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
// Close the socket when finished.
if(bIsfinished)
{
close(acceptedSocketHdl);
close(listenSocketHdl);
}
}
}
}
/* This function needs to be called from main function. For the callbacks to be invoked correctly, the API
m2m_wifi_handle_events should be called continuously from main. */
void tcpStartServer(uint16 u16ServerPort)
{
struct sockaddr_in strAddr;
// Initialize the socket layer.
socketInit();
// Register socket application callbacks.
registerSocketCallback(tcpServerSocketEventHandler, NULL);
// Create the server listen socket.
listenSocketHdl = socket(AF_INET, SOCK_STREAM, 0);
if(listenSocketHdl >= 0)
{
strAddr.sin_family
= AF_INET;
strAddr.sin_port
= _htons(u16ServerPort);
strAddr.sin_addr.s_addr
= 0; //INADDR_ANY
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bind(listenSocketHdl, (struct sockaddr*)&strAddr, sizeof(struct sockaddr_in));
}
}
9.4.3
UDP Client Example Code
SOCKET
uint8
clientSocketHdl;
rxBuffer[256], acSendBuffer[256];
/* Socket event handler */
void udpClientSocketEventHandler(SOCKET sock, uint8 u8Msg, void * pvMsg)
{
if((u8Msg == SOCKET_MSG_RECV) || (u8Msg == SOCKET_MSG_RECVFROM))
{
tstrSocketRecvMsg *pstrRecvMsg = (tstrSocketRecvMsg*)pvMsg;
if((pstrRecvMsg->pu8Buffer != NULL) && (pstrRecvMsg->s16BufferSize > 0))
{
uint16 len;
// Format a message in the acSendBuffer and put its length in len
sendto(clientSocketHdl, acSendBuffer, len, 0,
(struct sockaddr*)&strAddr, sizeof(struct sockaddr_in));
recvfrom(clientSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
// Close the socket after finished
close(clientSocketHdl);
}
}
}
/* This function needs to be called from main function. For the callbacks to be invoked correctly, the API
m2m_wifi_handle_events should be called continuously from main.
*/
void udpClientStart(char *pcServerIP)
{
struct sockaddr_in strAddr;
// Initialize the socket layer.
socketInit();
// Register socket application callbacks.
registerSocketCallback(udpClientSocketEventHandler, NULL);
clientSocketHdl = socket(AF_INET,SOCK_STREAM,u8Flags);
if(clientSocketHdl >= 0)
{
uint16 len;
strAddr.sin_family
= AF_INET;
strAddr.sin_port
= _htons(1234);
strAddr.sin_addr.s_addr = nmi_inet_addr(pcServerIP);
// Format some message in the acSendBuffer and put its length in len
sendto(clientSocketHdl, acSendBuffer, len, 0, (struct sockaddr*)&strAddr,
sizeof(struct sockaddr_in));
recvfrom(clientSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
}
}
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9.4.4
UDP Server Example Code
SOCKET
uint8
serverSocketHdl;
rxBuffer[256];
/* Socket event handler.
*/
void udpServerSocketEventHandler(SOCKET sock, uint8 u8Msg, void * pvMsg)
{
if(u8Msg == SOCKET_MSG_BIND)
{
tstrSocketBindMsg *pstrBind = (tstrSocketBindMsg*)pvMsg;
if(pstrBind->status == 0)
{
// call Recv
recvfrom(serverSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
}
else
{
printf("Bind Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_RECV)
{
tstrSocketRecvMsg *pstrRecvMsg = (tstrSocketRecvMsg*)pvMsg;
if((pstrRecvMsg->pu8Buffer != NULL) && (pstrRecvMsg->s16BufferSize > 0))
{
// Perform data exchange.
uint8
acSendBuffer[256];
uint16
u16MsgSize;
// Fill in the acSendBuffer with some data
// Send some data to the same address.
sendto(acceptedSocketHdl, acSendBuffer, u16MsgSize, 0,
pstrRecvMsg-> strRemoteAddr, sizeof(pstrRecvMsg-> strRemoteAddr));
// call Recv
recvfrom(serverSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
// Close the socket when finished.
close(serverSocketHdl);
}
}
}
/* This function needs to be called from main function. For the callbacks to be invoked correctly, the API
m2m_wifi_handle_events should be called continuously from main.
*/
void udpStartServer(uint16 u16ServerPort)
{
struct sockaddr_in strAddr;
// Initialize the socket layer.
socketInit();
// Register socket application callbacks.
registerSocketCallback(udpServerSocketEventHandler, NULL);
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// Create the server listen socket.
listenSocketHdl = socket(AF_INET, SOCK_DGRAM, 0);
if(listenSocketHdl >= 0)
{
strAddr.sin_family
= AF_INET;
strAddr.sin_port
= _htons(u16ServerPort);
strAddr.sin_addr.s_addr
= 0; //INADDR_ANY
bind(serverSocketHdl, (struct sockaddr*)&strAddr, sizeof(struct sockaddr_in));
}
}
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10
Transport Layer Security (TLS)
The Transport Layer Security layer sits on top of TCP and provides security services including privacy,
authenticity, and message integrity. Various security methods are available with TLS in ATWINC firmware.
ATWINC implements the Transport Layer Security protocol TLS v1.0, client mode.
10.1
TLS Connection Establishment
From the application’s point of view, the TLS functionality is wrapped behind the socket APIs. This hides the
complexity of TLS from the application which could use the TLS in the same fashion as the TCP client. The
main difference between TLS sockets and regular TCP sockets is that the application sets the
SOCKET_FLAGS_SSL while creating the TLS client socket. The detailed sequence of TLS connection
establishment is described in Figure 10-1.
Do not miss both the SOCKET_FLAGS_SSL flag and the correct port number in your TLS
application. For instance an HTTP client application shall use no flags when calling
socket API function and connect to port 80. The same application source code becomes an HTTPS client application if you use the flag SOCKET_FLAGS_SSL and change
the port number to connect to port 433.
Figure 10-1.
TLS Connection Establishment
HOST
DRIVER
APPLICATION
WINC
socket(SOCK_FLAGS_SSL)
sslSocketHdl
connect(sslSocketHdl)
SOCKET_CMD_SSL_CONNECT
Create SSL Session
TLS Handshake
SOCKET_MSG_CONNECT
SOCKET_CMD_SSL_CONNECT
Data Exchange (send/recv)
close(sslSocketHdl)
SOCKET_CMD_SSL_CLOSE
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10.2
Server Certificate Installation
10.2.1 Technical Background
10.2.1.1 Public Key Infrastructure
The TLS security is based on the Public Key Infrastructure PKI, in which:

A server has its public key stored in a digital certificate with X.509 standard format

The server must have its X.509 certificate issued by Certificate Authority CA which is in turn might be
certified by another CA


This structure forms a chain of X.509 certificates known as chain of trust
The top most CA of the Chain is known to be the Trusted Root Certificate Authority of the chain
10.2.1.2 TLS Server Authentication

When a TLS client initiates a connection with a server, the server sends its X.509 certificate chain (may
or may not include the root certificate) to the client

The client must authenticate the Server (verify the Server identity) before starting data exchange

The client must verify the entire certificate chain and also verify that the root certificate authority of the
chain is in the client’s trusted root certificate store
10.2.2 Adding a Certificate to the ATWINC Trusted Root Certificate Store



Before connecting to a TLS Server, the root certificate of the server must be installed on the
ATWINC3400. If this is not done, the TLS Connection to the server is aborted locally by ATWINC.
The root certificate must be in DER format. If it is not provided in DER format, it must be converted before
installation. See Appendix A for certificate formats and conversion methods.
To install the certificate, execute root_certificate_downloader.exe with the following syntax:
root_certificate_downloader.exe -n N File1.cer File2.cer .. FileN.cer
Refer to Appendix C for more information on how to download X509 certificates on ATWINC serial flash.
10.3
ATWINC TLS Limitations
10.3.1 Modes of Operation
The current TLS implementation supports TLSv1.0 Client operation only. TLS Server is not supported.
10.3.2 Concurrent Connections
Only two TLS concurrent connections are allowed.
10.3.3 Supported Cipher Suites
The current implementation is limited to the following cipher suites:

TLS_RSA_WITH_AES_128_CBC_SHA

TLS_RSA_WITH_AES_256_CBC_SHA

TLS_RSA_WITH_AES_128_CBC_SHA256

TLS_RSA_WITH_AES_256_CBC_SHA256
10.3.4 Supported Hash Algorithms
The current implementation supports MD5, SHA-1, and SHA256 hash algorithms.
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10.4
SSL Client Code Example
SOCKET
uint8
sslSocketHdl;
rxBuffer[256];
/* Socket event handler.
*/
void SSL_SocketEventHandler(SOCKET sock, uint8 u8Msg, void * pvMsg)
{
if(sock == sslSocketHdl)
{
if(u8Msg == SOCKET_MSG_CONNECT)
{
// Connect event
tstrSocketConnectMsg *pstrConnect = (tstrSocketConnectMsg*)pvMsg;
if(pstrConnect->s8Error == 0)
{
// Perform data exchange.
uint8
acSendBuffer[256];
uint16
u16MsgSize;
// Fill in the acSendBuffer with some data here
// Send some data.
send(sock, acSendBuffer, u16MsgSize, 0);
// Recv response from server.
recv(sslSocketHdl, rxBuffer, sizeof(rxBuffer), 0);
}
else
{
printf("SSL Connection Failed\n");
}
}
else if(u8Msg == SOCKET_MSG_RECV)
{
tstrSocketRecvMsg *pstrRecvMsg = (tstrSocketRecvMsg*)pvMsg;
if((pstrRecvMsg->pu8Buffer != NULL) && (pstrRecvMsg->s16BufferSize > 0))
{
// Process the received message here
// Close the socket if finished.
close(sslSocketHdl);
}
}
}
}
/* This is the DNS callback. The response of gethostbyname is here.
*/
void dnsResolveCallback(uint8* pu8HostName, uint32 u32ServerIP)
{
struct sockaddr_in strAddr;
if(u32ServerIP != 0)
{
sslSocketHdl = socket(AF_INET,SOCK_STREAM,u8Flags);
if(sslSocketHdl >= 0)
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{
strAddr.sin_family
= AF_INET;
strAddr.sin_port
= _htons(443);
strAddr.sin_addr.s_addr
= u32ServerIP;
connect(sslSocketHdl, (struct sockaddr*)&strAddr, sizeof(struct sockaddr_in));
}
}
else
{
printf("DNS Resolution Failed\n");
}
}
/* This function needs to be called from main function. For the callbacks to be invoked correctly, the API
m2m_wifi_handle_events should be called continuously from main.
*/
void SSL_Connect(char *pcServerURL)
{
// Initialize the socket layer.
socketInit();
// Register socket application callbacks.
registerSocketCallback(SSL_SocketEventHandler, dnsResolveCallback);
// Resolve Server URL.
gethostbyname((uint8*)pcServerURL);
}
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11
Wi-Fi AP Mode
11.1
Overview
This chapter provides an overview of ATWINC Access Point (AP) mode and describes how to set up this mode
and configure its parameters.
11.2
Setting ATWINC AP Mode
ATWINC AP mode configuration parameters should be set first by using the tstrM2MAPConfig structure.
There are two functions to enable/disable AP mode:

sint8 m2m_wifi_enable_ap(CONST tstrM2MAPConfig* pstrM2MAPConfig)

sint8 m2m_wifi_disable_ap(void);
For more information about structure and APIs, refer to the API reference in the
WINC3400_IoT_SW_APIs.chm that was supplied in the WINC3400_IoT_REL software package.
11.3
11.4
Limitations

AP mode supports OPEN and WEP security only

The AP can only support a single associated station. Further connection attempts will be rejected.

Concurrency (simultaneous STA/P2P and AP mode) is not supported. Before activating the AP mode,
host MCU application should disable the mode currently running.
Sequence Diagram
Once the AP mode has been established, no data interface exists until after a station associates to the AP.
Therefore the application needs to wait until it receives a notification via an event callback. This process is
shown in Figure 11-1.
Figure 11-1.
ATWINC AP Mode Establishment
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11.5
AP Mode Code Example
The following example shows how to configure ATWINC AP Mode with “WINC_SSID” as broadcasted SSID on
channel one with open security and an IP address equals 192.168.1.1.
#include "m2m_wifi.h"
#include "m2m_types.h"
void wifi_event_cb(uint8 u8WiFiEvent, void * pvMsg)
{
switch(u8WiFiEvent)
{
case M2M_WIFI_REQ_DHCP_CONF:
{
uint8 *pu8IPAddress = (uint8*)pvMsg;
printf("Associated STA has IP Address \"%u.%u.%u.%u\"\n", pu8IPAddress[0],
pu8IPAddress[1], pu8IPAddress[2], pu8IPAddress[3]);
}
break;
default:
break;
}
}
int main()
{
tstrWifiInitParam param;
/* Platform specific initializations. */
param.pfAppWifiCb = wifi_event_cb;
if (!m2m_wifi_init(&param))
{
tstrM2MAPConfig apConfig;
strcpy(apConfig.au8SSID, "WINC_SSID");
apConfig.u8SsidHide = SSID_MODE_VISIBLE;
apConfig.u8ListenChannel = 1;
apConfig.u8SecType = M2M_WIFI_SEC_WEP;
apConfig.u8KeyIndx = 0;
apConfig.u8KeySz = WEP_40_KEY_STRING_SIZE;
strcpy(apConfig.au8WepKey, "1234567890");
// IP Address
apConfig.au8DHCPServerIP[0]
apConfig.au8DHCPServerIP[1]
apConfig.au8DHCPServerIP[2]
apConfig.au8DHCPServerIP[3]
=
=
=
=
// Set SSID
// Set SSID to be broadcasted
// Set Channel
//
//
//
//
Set
Set
Set
Set
Security to WEP
WEP Key Index
WEP Key Size
WEP Key
192;
168;
1;
1;
// Start AP mode
m2m_wifi_enable_ap(&apConfig);
while(1)
{
m2m_wifi_handle_events(NULL);
}
}
}
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12
Provisioning
For normal operation the ATWINC device needs certain parameters to be loaded. In particular, when operating
in station mode, it needs to know the identity (SSID) and credentials of the access point to which it will connect.
The entry of this information is facilitated through the following provisioning steps.
The ATWINC3400 software supports three methods of provisioning:
12.1

BLE based in which a SmartPhone detects the ATWINC and uses an APP to transfer the information
from the user to the ATWINC3400

HTTP-based (browser) provisioning while ATWINC is in AP mode

Wi-Fi Protected Setup (WPS)
BLE Provisioning
This mode of provisioning is a major feature of the ATWINC3400 and is likely to be the method of choice. It has
the advantage that it is simple and intuitive for the user and does not disrupt normal SmartPhone operation
during the process.
In this method the host MCU instructs the ATWINC3400 to enable the BLE provisioning mode using API
m2m_wifi_start_ble_provision_mode. This causes the BLE to be activated and to start issuing BLE
beacons. The beacons will be detected by a suitable SmartPhone, which will inform the user that the device is
available for provisioning and provide information about the APP required to complete the process. When the
user obtains/runs the APP it will request the provisioning information and transfer to the ATWINC3400. The
ATWINC3400 will store the information and then connect to the specified AP, thus making itself ready for use.
The user needs to load the Atmel_IoT APP on either iOS or Andorid Smartphone. Upon launching the APP will
search for ATWINC3400 based products that are available for provisioning. A list of products will be displayed
using their user-friendly names:
When the user selects a product and clicks the ‘>’ symbol, the Access Points visible to the IoT device will be
shown on the screen:
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The user may then select the Access Point to which he wants to connect the IoT device and enter the
Passphrase at the top of the screen. After the information is entered, the provisioning information is passed to
the device using BLE and then passed on to the Wi-Fi component of the ATWINC3400. The Wi-Fi component
passes the credentials to the host using the callback M2M_WIFI_RESP_PROVISION_INFO and placing the
information in the structure tstrM2MProvisionInfo.
Figure 12-1.
BLE Provisioning Sequence Diagram
APPLICATION
HOST
DRIVER
WINC
USER DEVICE
m2m_wifi_start_ble_provision_mode
M2M_WIFI_REQ_START_BLE_PROVISION_MODE
BLE hardware activated
Beaconing
Run Atmel_IoT
App
Beacons detected by User device and
presented to user
BLE
User selects device and
observes list of Aps
seen by device
User selects AP and
enter PassPhrase
Credentials passed to
BLE in WINC3400
Credentials passed to
Wi-Fi in WINC3400
Credentials passed to WiFi in WINC3400
Turn off BLE module
M2M_WIFI_RESP_PROVISION_INFO
M2M_WIFI_RESP_PROVISION_INFO
Wi-Fi Connection
Procedure
Figure 12-1 shows the provisioning operation for an ATWINC device. The detailed steps are described in the
code example below.
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12.1.1 BLE Provisioning Code Example
void wifi_event_cb(uint8 u8WiFiEvent, void * pvMsg)
{
if(u8WiFiEvent == M2M_WIFI_RESP_PROVISION_INFO)
{
tstrM2MProvisionInfo *provInfo = (tstrM2MProvisionInfo*)pvMsg;
if(provInfo->u8Status == M2M_SUCCESS)
{
// connect to the provisioned AP.
m2m_wifi_connect((char*)provInfo->au8SSID, strlen(provInfo ->au8SSID),
provInfo->u8SecType, provInfo->au8Password, M2M_WIFI_CH_ALL);
printf("PROV SSID : %s\n", provInfo->au8SSID);
printf("PROV PSK : %s\n", provInfo->au8Password);
}
else
{
printf("(ERR) Provisioning Failed\n");
}
}
}
int main()
{
tstrWifiInitParam
param;
// Platform specific initializations.
// Driver initialization.
param.pfAppWifiCb = wifi_event_cb;
if(!m2m_wifi_init(&param))
{
m2m_wifi_start_ble_provision_mode();
while(1)
{
m2m_wifi_handle_events(NULL);
}
}
}
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12.2
HTTP Provisioning
12.2.1 Introduction
In this method, the ATWINC is placed in AP mode and another device with a browser capability (mobile phone,
tablet, PC, etc.) is instructed to connect to the ATWINC HTTP server. Once connected, the desired
configuration can be entered.
12.2.2 Limitations
The current implementation of the HTTP Provisioning has the following limitations:

ATWINC AP limitations apply in provisioning mode. See Section 11.3: Limitations for a list of AP mode
limitations.

Provisioning uses AP mode with open security. No Wi-Fi security nor application level security (e.g. TLS)
is used and therefore the AP credentials entered by the user are sent on the clear and can be seen by
eavesdroppers.

The ATWINC Provisioning home page is a static HTML page. No server-side scripting allowed in the
ATWINC HTTP server.

Only APs with WPA-personal security (passphrase based) and no security (Open network) can be
provisioned. WEP and WPA-Enterprise APs cannot be provisioned.

The Provisioning is responsible to deliver the connection parameters to the application, the connection
procedure and the connection parameters validity its application responsibility
12.2.3 Basic Approach
The HTTP provisioning home page is as shown in Figure 12-2.
Figure 12-2.
54
ATWINC HTTP Provisioning Page
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12.2.4 Provisioning Control Flow
Figure 12-3.
HTTP Provisioning Sequence Diagram
APPLICATION
HOST
DRIVER
WINC
USER DEVICE
m2m_wifi_start_provision_mode
M2M_WIFI_REQ_START_PROVISION_MODE
AP On, sending Beacons
HTTP Server is UP
Select WINC AP from
Wi-Fi Scan List
Wi-Fi Connection Establishment and DHCP
1- The user launches
the web browser and
opens the WINC home
page (e.g. “http://
HTTP Traffic wincconf.com”)
2- The user presses
“REFRESH”, touches an
AP from the SCAN
results table and then
types its password.
Turn off AP and
Destroy the HTTP
Server
M2M_WIFI_RESP_PROVISION_INFO
M2M_WIFI_RESP_PROVISION_INFO
Wi-Fi Connection
Procedure
Figure 12-3 shows the provisioning operation for an ATWINC device. The detailed steps are described as
follows:
1.
The ATWINC device starts the HTTP Provisioning mode.
2.
A user with a smart phone finds the ATWINC AP SSID in the Wi-Fi search list.
3.
The user connects to the ATWINC AP.
4.
The user launches the web browser and writes the ATWINC home page in the address bar.
5.
If the HTTP redirect is enabled at the ATWINC, any web address the ATWINC home page will load
automatically (like connecting to a public Wi-Fi hotspot). Some phones will display a notification
message “sign in to Wi-Fi networks?” which, when accepted, will load the ATWINC home pages load
automatically. The ATWINC home page (shown in Figure 12-2) will appear on the browser.
6.
To discover the list of Wi-Fi APs in the area, the user can press “Refresh”.
7.
The desired AP is then selected from the search list (by one click or one touch) and its name will appear
automatically in the “Network Name” text box.
8.
Then the user must enter the correct AP passphrase (for WPA/WPA2 personal security) in the “Pass
Phrase” text box. If the AP is not secured (Open network) the field should be left empty.
9.
An ATWINC device name may be optionally configured if desired by the user in the “Device Name” text
box.
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10. The user presses “Connect”.
The ATWINC will then turn off AP mode and start connecting to the provisioned AP.
12.2.5 HTTP Redirect Feature
The ATWINC HTTP provisioning server supports the HTTP redirect feature, which forces all HTTP traffic
originating from the associated user device to be redirected to the ATWINC provisioning home page.
This simplifies the mechanism of loading the provisioning page instead of typing the exact web address of the
http provisioning server.
To enable this feature, the redirect flag should be set when calling the API
m2m_wifi_start_provision_mode. See the below code example for details.
12.2.6 HTTP Provisioning Code Example
void wifi_event_cb(uint8 u8WiFiEvent, void * pvMsg)
{
if(u8WiFiEvent == M2M_WIFI_RESP_PROVISION_INFO)
{
tstrM2MProvisionInfo *provInfo = (tstrM2MProvisionInfo*)pvMsg;
if(provInfo->u8Status == M2M_SUCCESS)
{
// connect to the provisioned AP.
m2m_wifi_connect((char*)provInfo->au8SSID, strlen(provInfo ->au8SSID),
provInfo->u8SecType, provInfo->au8Password, M2M_WIFI_CH_ALL);
printf("PROV SSID : %s\n", provInfo->au8SSID);
printf("PROV PSK : %s\n", provInfo->au8Password);
}
else
{
printf("(ERR) Provisioning Failed\n");
}
}
}
int main()
{
tstrWifiInitParam
param;
// Platform specific initializations.
// Driver initialization.
param.pfAppWifiCb = wifi_event_cb;
if(!m2m_wifi_init(&param))
{
tstrM2MAPConfig apConfig;
uint8 bEnableRedirect = 1;
strcpy(apConfig.au8SSID,
apConfig.u8ListenChannel
apConfig.u8SecType
apConfig.u8SsidHide
"WINC_AP");
= 1;
= M2M_WIFI_SEC_OPEN;
= 0;
// IP Address
apConfig.au8DHCPServerIP[0]
apConfig.au8DHCPServerIP[1]
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= 192;
= 168;
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apConfig.au8DHCPServerIP[2]
apConfig.au8DHCPServerIP[0]
= 1;
= 1;
m2m_wifi_start_provision_mode(&apConfig, "atmelconfig.com", bEnableRedirect);
while(1)
{
m2m_wifi_handle_events(NULL);
}
}
}
12.3
Wi-Fi Protected Setup (WPS)
Most modern Access Points support the Wi-Fi Protected Setup method, typically using the push button
method. From the user’s perspective WPS is a simple mechanism to make a device connect securely to an AP
without remembering passwords or passphrases. WPS uses asymmetric cryptography to form a temporary
secure link which is then used to transfer a passphrase (and other information) from the AP to the new station.
After the transfer, secure connections are made as for normal static PSK configuration.
12.3.1 WPS Configuration Methods
There are two authentication methods that can be used with WPS:
1.
PBC (Push button) method
A physical button is pressed on the AP, which puts the AP into WPS mode for a limited period of time.
WPS is initiated on the ATWINC3400 by calling m2m_wifi_wps with input parameter WPS_PBC_TRIGGER.
2.
PIN method
The AP is always available for WPS initiation but requires proof that the user has knowledge of an 8-digit
PIN, usually printed on the body of the AP. Because ATWINC is often used in “headless” devices (no
user interface) it is necessary to reverse this process and force the AP to use a PIN number provided
with the ATWINC device. Some APs allow the PIN to be changed through configuration. WPS is initiated
on the ATWINC3400 by calling m2m_wifi_wps with input parameter WPS_PIN_TRIGGER. Given the
difficulty of this approach it is not recommend for most applications.
The flow of messages and actions for WPS operation is shown in Figure 12-4.
12.3.2 WPS Limitations

WPS is used to transfer the WPA/WPA2 key only; other security types are not supported

The WPS standard will reject the session (WPS response fail) if the WPS button pressed on more than
one AP in the same proximity, and the application should try after couple of minutes

If no WPS button pressed on the AP, the WPS scan will timeout after two minutes since the initial WPS
trigger

The WPS is responsible to deliver the connection parameters to the application, the connection
procedure and the connection parameters validity is the application responsibility
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12.3.3 WPS Control Flow
Figure 12-4.
WPS Operation for Push Button Trigger
APPLICATION
HOST
DRIVER
WINC
m2m_wifi_wps
M2M_WIFI_REQ_WPS
Start WPS Scan
WPS Button
Pressed on AP
WPS Registration
Protocol
WPS Session Ends
and AP credentials
are obtained
M2M_WIFI_REQ_WPS
M2M_WIFI_REQ_WPS
Wi-Fi Connection
Procedure
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12.3.4 WPS Code Example
void wifi_event_cb(uint8 u8WiFiEvent, void * pvMsg)
{
if(u8WiFiEvent == M2M_WIFI_REQ_WPS)
{
tstrM2MWPSInfo *pstrWPS = (tstrM2MWPSInfo*)pvMsg;
if(pstrWPS->u8AuthType != 0)
{
printf("WPS SSID
: %s\n",pstrWPS->au8SSID);
printf("WPS PSK
: %s\n",pstrWPS->au8PSK);
printf("WPS SSID Auth Type : %s\n",
pstrWPS->u8AuthType == M2M_WIFI_SEC_OPEN ? "OPEN" : "WPA/WPA2");
printf("WPS Channel
: %d\n",pstrWPS->u8Ch + 1);
// Establish Wi-Fi connection
m2m_wifi_connect((char*)pstrWPS->au8SSID, (uint8)m2m_strlen(pstrWPS->au8SSID),
pstrWPS->u8AuthType, pstrWPS->au8PSK, pstrWPS->u8Ch);
}
else
{
printf("(ERR) WPS Is not enabled OR Timedout\n");
}
}
}
int main()
{
tstrWifiInitParam
param;
// Platform specific initializations.
// Driver initialization.
param.pfAppWifiCb
= wifi_event_cb;
if(!m2m_wifi_init(&param))
{
// Trigger WPS in Push button mode.
m2m_wifi_wps(WPS_PBC_TRIGGER, NULL);
while(1)
{
m2m_wifi_handle_events(NULL);
}
}
}
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13
Multicast Sockets
13.1
Overview
The purpose of the multicast filters is to provide the ability to send/receive messages to/from multicast
addresses. This feature is useful for one-to-many communication over networks, whether it is intended to send
Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission, participate in a
zero-configuration networking or listening to a multicast stream or any other application.
13.2
How to use Filters
Whenever the application wishes to use a multicast IP address, for either sending or receiving, a filter is
needed. The application can establish this through setting the IP_ADD_MEMBERSHIP option for the required
socket accompanied by the multicast address that the application wants to use. If subsequently the host wants
to stop receiving the multicast stream it should set the IP_DROP_MEMBERSHIP option for the required socket
accompanied with the multicast address.
Adding or removing a multicast address filter will cause ATWINC chip firmware to add/remove both MAC layer
filter and IP layer filter in order to pass or prevent messages from reaching to host.
13.3
Multicast Socket Code Example
In order to illustrate the functionality, a simple example is implemented where the host application responds to
mDNS (Multicast Domain Name System) queries sent from a Computer/Mobile application. The
Computer/Mobile is looking for devices which support the zero configuration service as indicated by an mDNS
response. The ATWINC responds, announcing its presence and its capability of sending and receiving
multicast messages.
The example consists of a UDP server that binds on port 5353 (mDNS port) and waits for messages, parsing
them and replying with a previously saved response message.

Server Initialization
void MDNS_ServerInit()
{
tstrSockAddr
strAddr ;
unsigned int MULTICAST_IP = 0xE00000FB; //224.0.0.251
socketInit();
dns_server_sock = socket( AF_INET, SOCK_DGRAM,0);
MDNS_INFO("DNS_server_init \n");
setsockopt(dns_server_sock,1,IP_ADD_MEMBERSHIP,&MULTICAST_IP,sizeof(MULTICAST_IP));
strAddr.u16Port =HTONS(MDNS_SERVER_PORT);
bind(dns_server_sock,(struct sockaddr*)&strAddr,sizeof(strAddr));
registerSocketCallback(UDP_SocketEventHandler,AppServerCb);
}

Sockets Events Handler
void MDNS_RecvfromCB(signed char sock,unsigned char *pu8RxBuffer,signed short s16DataSize,
unsigned char *pu8IPAddr,unsigned short u16Port,void *pvArg)
{
MDNS_INFO("DnsServer_RecvfromCB \n");
if((pu8RxBuffer != 0) && (s16DataSize > 0))
{
tstrDnsHdr strDnsHdr;
strdnsquery;
MDNS_INFO("DNS Packet Recieved \n");
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if(MDNS_ParseQuery(&pu8RxBuffer[0], &strDnsHdr,&strDnsQuery))
MDNS_SendResp (sock,pu8IPAddr, u16Port,&strDnsHdr,&strDnsQuery );
}
else
{
MDNS_INFO("DnsServer_RecvfromCB Error !\n");
}
}

Server Socket Callback
void MDNS_RecvfromCB(signed char sock,unsigned char *pu8RxBuffer,signed short
s16DataSize,unsigned char *pu8IPAddr,unsigned short
u16Port,void *pvArg)
{
MDNS_INFO("DnsServer_RecvfromCB \n");
if((pu8RxBuffer != 0) && (s16DataSize > 0))
{
tstrDnsHdr strDnsHdr ;
strdnsquery ;
MDNS_INFO("DNS Packet Recieved \n");
if(MDNS_ParseQuery(&pu8RxBuffer[0], &strDnsHdr,&strDnsQuery))
MDNS_SendResp (sock,pu8IPAddr, u16Port,&strDnsHdr,&strDnsQuery );
}
else
{
MDNS_INFO("DnsServer_RecvfromCB Error !\n");
}
}

Parse mDNS Query
int MDNS_ParseQuery(unsigned char * pu8RxBuffer, tstrDnsHdr *pstrDnsHdr, strdnsquery *pstrDnsQuery )
{
unsigned char dot_size,temp=0;
unsigned short n=0,i=0,u16index=0;
int bDNSmatch = 0;
/* ----Identification--------------------------|QR| Opcode
|AA|TC|RD|RA|Z|AD|CD|Rcode
| */
/*
----Total Questions------------------------|-----------------Total Answer RRs--------------*/
/*
----Total Authority RRs --------------------|----------------Total Additional RRs-----------*/
/*
--------------------------------Questions
--------------------------------*/
/*
------------------------------------ Answer RRs ------------------------------------------*/
/*
----------------------------------- Authority RRs
---------------------------------*/
/*
-----------------------------------Additional RRs
---------------------------------*/
MDNS_INFO("Parsing DNS Packet\n");
pstrDnsHdr->id = (( pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
MDNS_INFO ("id = %.4x \n",pstrDnsHdr->id);
u16index+=2;
pstrDnsHdr->flags1= pu8RxBuffer[u16index++];
pstrDnsHdr->flags2= pu8RxBuffer[u16index++];
MDNS_INFO ("flags = %.2x %.2x \n",pstrDnsHdr->flags1,pstrDnsHdr->flags2);
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pstrDnsHdr->numquestions = ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
MDNS_INFO ("numquestions = %.4x \n",pstrDnsHdr->numquestions);
u16index+=2;
pstrDnsHdr->numanswers = ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
MDNS_INFO ("numanswers = %.4x \n",pstrDnsHdr->numanswers);
u16index+=2;
pstrDnsHdr->numauthrr = ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
MDNS_INFO ("numauthrr = %.4x \n",pstrDnsHdr->numauthrr);
u16index+=2;
pstrDnsHdr->numextrarr = ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
MDNS_INFO ("numextrarr = %.4x \n",pstrDnsHdr->numextrarr);
u16index+=2;
dot_size =pstrDnsQuery->query[n++]= pu8RxBuffer[u16index++];
pstrDnsQuery->u16size=1;
while (dot_size--!=0) //(pu8RxBuffer[++u16index] != 0)
{
pstrDnsQuery->query[n++]=pstrDnsQuery->queryForChecking[i++]=pu8RxBuffer[u16index++] ;
pstrDnsQuery->u16size++;
gu8pos=temp;
if (dot_size == 0 )
{
pstrDnsQuery->queryForChecking[i++]= '.' ;
temp=u16index;
dot_size =pstrDnsQuery->query[n++]= pu8RxBuffer[u16index++];
pstrDnsQuery->u16size++;
}
}
pstrDnsQuery->queryForChecking[--i] = 0;
MDNS_INFO("parsed query <%s>\n",pstrDnsQuery->queryForChecking);
// Search for any match in the local DNS table.
for(n = 0; n < DNS_SERVER_CACHE_SIZE; n++)
{
MDNS_INFO("Saved URL <%s>\n",gpacDnsServerCache[n]);
if(strcmp(gpacDnsServerCache[n], pstrDnsQuery->queryForChecking) ==0)
{
bDNSmatch= 1;
MDNS_INFO("MATCH \n");
}
else
{
MDNS_INFO("Mismatch\n");
}
}
pstrDnsQuery->u16class = ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
u16index+=2;
pstrDnsQuery->u16type= ((pu8RxBuffer[u16index]<<8)| (pu8RxBuffer[u16index+1]));
return bDNSmatch;
}
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
Send mDNS Response:
void MDNS_SendResp (signed char sock,unsigned char * pu8IPAddr,
unsigned short u16Port,tstrDnsHdr *pstrDnsHdr,strdnsquery *pstrDnsQuery)
{
unsigned short u16index=0;
tstrSockAddr strclientAddr ;
unsigned char * pu8sendBuf;
char * serviceName2 = (char*)malloc(sizeof(serviceName)+1);
unsigned int MULTICAST_IP = 0xFB0000E0;
pu8sendBuf= gPu8Buf;
memcpy(&strclientAddr.u32IPAddr,&MULTICAST_IP,IPV4_DATA_LENGTH);
strclientAddr.u16Port=u16Port;
MDNS_INFO("%s \n",pstrDnsQuery->query);
MDNS_INFO("Query Size = %d \n",pstrDnsQuery->u16size);
MDNS_INFO("class = %.4x \n",pstrDnsQuery->u16class);
MDNS_INFO("type = %.4x \n",pstrDnsQuery->u16type);
MDNS_INFO("PREPARING DNS ANSWER BEFORE SENDING\n");
/*----------------------------ID 2 Bytes -----------------------------*/
pu8sendBuf [u16index++] =0; //( pstrDnsHdr->id>>8);
pu8sendBuf [u16index++] = 0;//( pstrDnsHdr->id)&(0xFF);
MDNS_INFO ("(ResPonse) id = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index-1]);
/*----------------------------Flags 2 Bytes----------------------------*/
pu8sendBuf [u16index++] = DNS_RSP_FLAG_1;
pu8sendBuf [u16index++] = DNS_RSP_FLAG_2;
MDNS_INFO ("(ResPonse) Flags = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index-1]);
/*----------------------------No of Questions--------------------------*/
pu8sendBuf [u16index++] =0x00;
pu8sendBuf [u16index++] =0x01;
MDNS_INFO ("(ResPonse) Questions = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index1]);
/*---------------------------No of Answers----------------------------*/
pu8sendBuf [u16index++] =0x00;
pu8sendBuf [u16index++] =0x01;
MDNS_INFO ("(ResPonse) Answers = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index-1]);
/*---------------------------No of Authority RRs------------------------*/
pu8sendBuf [u16index++] =0x00;
pu8sendBuf [u16index++] =0x00;
MDNS_INFO ("(ResPonse) Authority RRs = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index1]);
/*----------------------------No of Additional RRs----------------------*/
pu8sendBuf [u16index++] =0x00;
pu8sendBuf [u16index++] =0x00;
MDNS_INFO ("(ResPonse) Additional RRs = %.2x %.2x \n", pu8sendBuf[u16index2],pu8sendBuf[u16index-1]);
/*--------------------------------Query-----------------------------*/
memcpy(&pu8sendBuf[u16index],pstrDnsQuery->query,pstrDnsQuery->u16size);
MDNS_INFO("\nsize = %d \n",pstrDnsQuery->u16size);
u16index+=pstrDnsQuery->u16size;
/*-------------------------------Query Type----------------------------*/
pu8sendBuf [u16index++] = ( pstrDnsQuery->u16type>>8);//MDNS_TYPE>>8;
pu8sendBuf [u16index++] = ( pstrDnsQuery->u16type)&(0xFF);//(MDNS_TYPE&0xFF);
MDNS_INFO ("Query Type = %.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index-1]);
/*------------------------------Query Class-----------------------------------*/
pu8sendBuf [u16index++] =MDNS_CLASS>>8;//(( pstrDnsQuery->u16class>>8)|0x80);
pu8sendBuf [u16index++] = (MDNS_CLASS & 0xFF);//( pstrDnsQuery->u16class)&(0xFF);
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MDNS_INFO ("Query Class =
%.2x %.2x \n", pu8sendBuf[u16index-2],pu8sendBuf[u16index-1]);
/*########################Answers#########################*/
/*------------------------------Name---------------------------------*/
pu8sendBuf [u16index++]= 0xC0 ; //pointer to query name location
pu8sendBuf [u16index++]= 0x0C ; // instead of writing the whole query name again
/*-----------------------------Type----------------------------------*/
pu8sendBuf [u16index++] =MDNS_TYPE>>8; //Type 12 PTR (domain name Pointer).
pu8sendBuf [u16index++] =(MDNS_TYPE&0xFF);
/*------------------------------Class-----------------------------------*/
pu8sendBuf [u16index++] =0x00;//MDNS_CLASS; //Class IN, Internet.
pu8sendBuf [u16index++] =0x01;// (MDNS_CLASS & 0xFF);
/*-----------------------------TTL----------------------------------*/
pu8sendBuf [u16index++] =(TIME_TO_LIVE >>24);
pu8sendBuf [u16index++] =(TIME_TO_LIVE >>16);
pu8sendBuf [u16index++] =(TIME_TO_LIVE >>8);
pu8sendBuf [u16index++] =(TIME_TO_LIVE );
/*---------------------------Date Length----------------------------------*/
pu8sendBuf [u16index++] =(sizeof(serviceName)+2)>>8;//added 2 bytes for the pointer
pu8sendBuf [u16index++] =(sizeof(serviceName)+2);
/*-----------------------------DATA--------------------------------*/
convertServiceName(serviceName,sizeof(serviceName),serviceName2);
memcpy(&pu8sendBuf[u16index],serviceName2,sizeof(serviceName)+1);
u16index+=sizeof(serviceName);
pu8sendBuf [u16index++] =0xC0;//Pointer to .local (from name)
pu8sendBuf [u16index++] =gu8pos;//23
/*###########################################################*/
strclientAddr.u16Port=HTONS(MDNS_SERVER_PORT);
// MultiCast RESPONSE
sendto( sock, pu8sendBuf,(uint16)u16index,0,(struct
sockaddr*)&strclientAddr,sizeof(strclientAddr));
strclientAddr.u16Port=u16Port;
memcpy(&strclientAddr.u32IPAddr,pu8IPAddr,IPV4_DATA_LENGTH);
}

Service Name
static char gpacDnsServerCache[DNS_SERVER_CACHE_SIZE][MDNS_HOSTNAME_SIZE] =
{
"_services._dns-sd._udp.local","_workstation._tcp.local","_http._tcp.local"
};
unsigned char
gPu8Buf [MDNS_BUF_SIZE];
unsigned char
gu8pos ;
signed
char
dns_server_sock ;
#define serviceName "_ATMELWIFI._tcp"
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14
ATWINC Serial Flash Memory
14.1
Overview and Features
The ATWINC has internal serial (SPI) flash memory of either 4 or 8Mb capacity. The flash memory is used to
store:

User configuration

Wi-Fi Firmware

BLE Firmware

Connection Profiles
During startup and mode changes the firmware is loaded from the serial flash into program memory (IRAM) in
which the firmware is executed. First the Wi-Fi firmware is loaded and started while holding the BLE processor
in reset. Then the BLE firmware is loaded and placed into the BLE memory prior to releasing reset. The flash is
accessed at other points during runtime to retrieve configuration and profile data.
The flash memory can be read, written to, and erased directly from the host without cooperation with the
ATWINC firmware. However, if operational firmware is already loaded, it is necessary to first halt any running
ATWINC firmware before accessing the serial flash to avoid access conflict between host and the ATWINC
processor.
14.2
Accessing to Serial Flash

The host has transparent access to the serial (SPI) flash through ATWINC SPI master

The host can program the serial (SPI) flash without need for operational firmware in the ATWINC. The
function m2m_wifi_download_mode must be called first.
Figure 14-1.
System Block Diagram showing SPI Flash Connection
WINC
Host MCU
14.3
I2C, SPI, UART
Wi-Fi ASIC
SPI Master
Serial Flash
Read/Write/Erase Operations
SPI Flash can be accessed to be read, written, and erased.
It is required to first change the ATWINC’s mode to “download mode” before any attempt to access the SPI
Flash by calling:
sint32 m2m_wifi_download_mode();
All SPI flash functions are blocking. A return of M2M_SUCCESS indicates that the requested operation has been
completed successfully.
The following is a list of flash functions that may be used:

Query the size of the SPI Flash:
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uint32 spi_flash_get_size();
This function returns with size of SPI Flash in Mb.

Read data from the SPI Flash:
sint8 spi_flash_read(uint8 *pu8Buf, uint32 u32offset, uint32 u32Sz)
Where the size of data is limited by SPI Flash size.

Erase sectors in the SPI Flash:
sint8 spi_flash_erase(uint32 u32Offset, uint32 u32Sz)
Note:
The size is limited by the SPI Flash size.
Before writing to any sector, this sector has to be erased first. So if some data needs to be changed
within a sector, it is advised to read the sector first, modify the data, then erase and write the whole
sector again.

Write data to the SPI Flash:
sint8 spi_flash_write(uint8* pu8Buf, uint32 u32Offset, uint32 u32Sz)
If the application wants to write any number of bytes within any sector, it has to erase the entire sector
first. It may be necessary to read the entire sector, erase the sector, and then write back with
modifications. It is also recommended to verify that data had been written after it returns success by
reading data again and compare it with the original.
14.4
Serial (SPI) Flash Map
The following map is valid for SPI Flash with size equals 8Mb (1MB)
Section
Offset [KB]
Boot firmware
0
4
Control Section
4
8
Configuration
12
8
Certificate
20
4
Scratch Section
24
4
Firmware Image – Wi-Fi
28
196
HTTP Files
224
8
Connection Parameters
232
4
Firmware Image – BLE
236
128
[Unused]
[364]
[148]
OTA Image – Wi-Fi and BLE
512
324
[Unused]
[836]
[188]
Total used
14.5
Size [KB]
684
Flash Read, Erase, Write Code Example
#include "spi_flash.h"
#define DATA_TO_REPLACE "THIS IS A NEW SECTOR IN FLASH"
int main()
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{
uint8 au8FlashContent[FLASH_SECTOR_SZ] = {0};
uint32u32FlashTotalSize = 0, u32FlashOffset = 0;
// Platform specific initializations.
ret = m2m_wifi_download_mode();
if(M2M_SUCCESS != ret)
{
printf("Unable to enter download mode\r\n");
}
else
{
u32FlashTotalSize = spi_flash_get_size();
}
while((u32FlashTotalSize > u32FlashOffset) && (M2M_SUCCESS == ret))
{
ret = spi_flash_read(au8FlashContent, u32FlashOffset, FLASH_SECTOR_SZ);
if(M2M_SUCCESS != ret)
{
printf("Unable to read SPI sector\r\n");
break;
}
memcpy(au8FlashContent, DATA_TO_REPLACE, strlen(DATA_TO_REPLACE));
ret = spi_flash_erase(u32FlashOffset, FLASH_SECTOR_SZ);
if(M2M_SUCCESS != ret)
{
printf("Unable to erase SPI sector\r\n");
break;
}
ret = spi_flash_write(au8FlashContent, u32FlashOffset, FLASH_SECTOR_SZ);
if(M2M_SUCCESS != ret)
{
printf("Unable to write SPI sector\r\n");
break;
}
u32FlashOffset += FLASH_SECTOR_SZ;
}
if(M2M_SUCCESS == ret)
{
printf("Successful operations\r\n");
}
else
{
printf("Failed operations\r\n");
}
while(1);
return M2M_SUCCESS;
}
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15
Writing a Simple Networking Application
This chapter provides a step-by-step tutorial on how to build a networking application from scratch. For details
on getting started with the Atmel Studio and how to setup the environment and obtain the example application
and AtmelWirelessConnect APK smart phone application, refer to [R01].
15.1
Prerequisites


15.2
Hardware Prerequisites
–
Atmel SAMD21-XPRO Evaluation kit
–
Atmel I/O1 Xplained ATIO1-XPRO board
–
Atmel ATWINC3400 Xplained Pro Extension board
–
Micro-USB Cable (Micro-A / Micro-B)
–
Android Phone
Software Prerequisites
–
Atmel Studio 6.2 (build 1153) or higher
–
Atmel Software Frameworks 3.15.0
–
Wi-Fi Network Controller demo for SAM D21
–
Android apk AtmelWirelessConnect application
Solution Overview
The goal of this project is to develop an IoT application, capable of sending temperature information to any
phone or tablet on the network while offering a way to remotely control the LED on the SAM D21 Xplained Pro
board.
To develop and run this project you need to start with the downloaded empty Wi-Fi example project.
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If you cannot use an Android phone to test the solution, you can still use Wireshark to
see the traffic generated by the IoT sensor application.
ATWINC3400 Wi-Fi extension and I/O1 extension should be plugged into SAM D21
Xplained Pro EXT1 and EXT2 respectively.
15.3
Project Creation
Open the empty Wi-Fi example Project.
15.4

Open Atmel Studio 6.2

Click on “File” then “Open Project/Solution…”

Select the Empty Wi-Fi example project on your hard drive
Wi-Fi Software API Files
The table below lists the main files from the Wi-Fi Software API located.
File
Description
m2m_wifi.h
m2m_wifi.c
socket.h
socket.c
nmbsp.h
nm_bsp_samd21.c
nm_bus_wrapper_samd21.c
Provide entry point, Wi-Fi configuration API
Provide socket API
Provide BSP APIs needed by Host Driver
Provide bus wrapper APIs needed by Host Driver
In order to add Wi-Fi connectivity into an existing user example project, the complete “wifi_nmi” folder should
be added to the user project.
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Locate these files in your project:
m2m_wifi_type.h is an internal type definition header file.
The configuration of the Wi-Fi Software API is fairly easy and relies on three configuration files.
The file conf_winc.h provides configuration for the following:




70
CONF_WIFI_M2M_RESET_PIN: Reset pin definition (RESET_N)
CONF_WIFI_M2M_CHIP_ENABLE_PIN: Reset pin definition (CHIP_EN)
CONF_WIFI_M2M_INT_PIN: Interrupt line (IRQN)
CONF_WIFI_M2M_DEUG: Debug enable
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15.5
Reading Temperature Sensor and Controlling LED Status
The empty Wi-Fi example Project comes with a specific driver for the AT30TSE temperature sensor, located on
the I/O1 extension.
The driver implementation can be found in the “ASF\sam0\components\sensor\at30tse75x” folder of the
Solution Explorer.
Retrieving the temperature information is easy and can be performed in three steps:
1.
Include the driver header file.
#include “asf.h”
2.
Initialize the temperature sensor driver.
at30tse_init();
3.
Retrieve the current temperature value.
double temp = at30tse_read_temperature();
The empty Wi-Fi example Project already includes the peripheral dependencies for the
temperature sensor.
The temperature sensor configuration file “conf_at30tse75x.h” is already configured to
use the peripheral on EXT2.
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15.6
Step By Step Development
The main.c file from the empty Wi-Fi example Project should already handle the system initialization and start.
It is also responsible for calling a demo_start() function (declared in demo.h and implemented in the demo.c
file).
The demo_start() function is the application main loop which implements the routines for connecting to the
network and sending temperature reports using the Wi-Fi Software API.
Implement the following steps to implement the IoT temperature sensor application.
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1.
Reset the ATWINC3400 Module.
To do so, we need to call nm_bsp_init(), which initializes the CHIP_EN and RESET_N GPIOs.
void demo_start(void)
{
/* Reset network controller */
nm_bsp_init();
while (1) {
/* TODO: Implement IOT feature here. */
}
}
2.
Initialize the Wi-Fi Software API.
To do so, we need to declare the tstrWifiInitParam structure which contains a pointer to the Wi-Fi
callback functions. A pointer to tstrWifiInitParam structure is passed to m2m_wifi_init().To
indicate successful initialization, m2m_wifi_init() returns M2M_SUCCESS. Later on, we call
socketInit() and register the socket callback.
tstrWifiInitParam param;
sint8 ret;
/* Initialize Wi-Fi parameters structure. */
param.pfAppWifiCb = m2m_wifi_state;
ret = m2m_wifi_init(&param);
if (M2M_SUCCESS != ret) {
puts("demo_start: nm_drv_init call error!");
while (1)
;
}
/* Initialize Socket module */
socketInit();
registerSocketCallback(m2m_wifi_socket_handler, NULL);
3.
Implement an empty m2m_wifi_state() function.
In order to receive Wi-Fi events from “m2m_wifi” module, implement a skeleton M2M Wi-Fi callback
function.
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
default:
break;
}
}
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4.
Implement an empty m2m_wifi_socket_handler.
In order to receive socket event from “socket” module, implement a skeleton M2M Socket callback
function.
static void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
{
/* TODO: Check for socket event here. */
}
All ATWINC3400 socket operations are non-blocking asynchronous operations.
When m2m_wifi_socket_handler() is called, it indicates a specific asynchronous socket operation has been
done for a specified SOCKET sock. The completed socket operation type is indicated in u8Msg parameter and
any message payload (e.g. received data) is provided in the last parameter pvMsg.
Example of non-blocking asynchronous socket operations completions are: SOCKET_MSG_BIND,
SOCKET_MSG_LISTEN, SOCKET_MSG_ACCEPT, SOCKET_MSG_CONNECT, SOCKET_MSG_RECV,
SOCKET_MSG_SEND, SOCKET_MSG_SENDTO, and SOCKET_MSG_RECVFROM to indicate completion of bind(),
listen(), accept(), connect(), recv(), send(), sendto(), recvfrom() respectively.
5.
Initialize the temperature sensor.
/* Initialize temperature sensor. */
at30tse_init();
6.
Initialize LED0 to off state.
During connection phase, LED0 of SAM D21 will be off. LED0 will turn on when the DHCP address is
acquired. After DHCP, the Android app will be able to control it remotely.
/* Turn LED0 off initially. */
port_pin_set_output_level(LED_0_PIN, true);
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Upon completion of this step, the code should look like the following:
static void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
{
/* TODO: Check for socket event here. */
}
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
default:
break;
}
}
/**
* \brief Demo main routine.
*/
void demo_start(void)
{
tstrWifiInitParam param;
sint8 ret;
/* Initialize Wi-Fi parameters structure. */
param.pfAppWifiCb = m2m_wifi_state;
/* Turn LED0 off initially. */
port_pin_set_output_level(LED_0_PIN, true);
/* Initialize temperature sensor. */
at30tse_init();
/* Reset network controller */
nm_bsp_init();
/* Initialize Wi-Fi driver with data and Wi-Fi status callbacks. */
ret = m2m_wifi_init(&param);
if (M2M_SUCCESS != ret) {
puts("demo_start: nm_drv_init call error!");
while (1)
;
}
/* Initialize Socket module */
socketInit();
registerSocketCallback(m2m_wifi_socket_handler, NULL);
while (1) {
/* TODO: Implement IOT feature here. */
}
}
The initialization stage is done. Now, connect to the network and open the required
communication sockets.
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7.
Add event handler to application main loop.
To do so, add a call to m2m_wifi_handle_events() inside the application loop.
The API m2m_wifi_handle_events() checks for pending events and dispatches events to m2m_wifi
module or socket module and returns to caller.
while (1) {
/* Handle pending events from network controller. */
m2m_wifi_handle_events(NULL);
}
Since the demo application does not use operating system, m2m_wifi_handle_events() is called in the application main loop. If the application used an operating system, it is required to create a dedicated task to call m2m_wifi_handle_events(). The task shall sleep until an interrupt on IRQN line, then it handles the
deferred work by ISR and calls m2m_wifi_handle_events().
Both of the application defined callbacks in “demo.c”: m2m_wifi_socket_handler()
and m2m_wifi_state() are called in the context of m2m_wifi_handle_events().
8.
Start association.
The SSID and passphrase of the router are defined in the demo.h file, using the following defines;
DEMO_WLAN_SSID and DEMO_WLAN_PSK. These should be updated with your local SSID and passphrase.
The m2m_wifi_connect() function request the ATWINC3400 Wi-Fi module to start association with the
local SSID.
/* Connect to router. */
m2m_wifi_connect((char *)DEMO_WLAN_SSID, sizeof(DEMO_WLAN_SSID),
DEMO_WLAN_AUTH, (char *)DEMO_WLAN_PSK, M2M_WIFI_CH_ALL);
The parameter DEMO_WLAN_AUTH specifies the local AP security type which can be either: OPEN, WEP,
WPA/WPA2, or enterprise security. The last parameter M2M_WIFI_CH_ALL forces the ATWINC3400 to
scan for the local AP on all channels.
The ATWINC3400 firmware contains a “fast boot feature” which optimizes the association time across power cycles. Firmware stores the channel on which the last successful association occurred. During next association attempt, firmware probes if the
local AP is still on the same channel (which is most likely to happen since AP does not
change channels frequently).
If local AP is not found, then firmware will trigger a new scan.
9.
Handle Wi-Fi connection state change in m2m_wifi_state().
Upon association success, the host driver will call m2m_wifi_state() with
M2M_WIFI_RESP_CON_STATE_CHANGED event to indicate the association state change. The event
message payload indicates whether connection succeeds or fails.
Add the following code to m2m_wifi_state() to handle M2M_WIFI_RESP_CON_STATE_CHANGED.
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/** Wi-Fi status variable. */
static volatile uint8 wifi_connected = 0;
...
...
...
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
case M2M_WIFI_RESP_CON_STATE_CHANGED: {
tstrM2mWifiStateChanged *pstrWifiState = (tstrM2mWifiStateChanged*) pvMsg;
if (pstrWifiState->u8CurrState == M2M_WIFI_CONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: CONNECTED");
m2m_wifi_request_dhcp_client();
}
else if(pstrWifiState->u8CurrState == M2M_WIFI_DISCONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: DISCONNECTED");
wifi_connected = 0;
m2m_wifi_connect((char *)DEMO_WLAN_SSID, sizeof(DEMO_WLAN_SSID),
DEMO_WLAN_AUTH, (char *)DEMO_WLAN_PSK, M2M_WIFI_CH_ALL);
}
break;
}
...
...
...
When association succeeds, M2M_WIFI_CONNECTED event is received. This implies the start of the DHCP
client to obtain IP address by calling m2m_wifi_request_dhcp_client(). If association fails or a
disconnection happens, M2M_WIFI_DISCONNECTED is received and the demo app will attempt to reconnect
again using m2m_wifi_connect().
10. Obtaining DHCP configuration.
When DHCP client in ATWINC3400 Firmware obtains IP address from local AP, the demo app receives
information about the obtained IP address. m2m_wifi_state() callback is invoked with
M2M_WIFI_REQ_DHCP_CONF event type.
Add the following code to m2m_wifi_state() to handle M2M_WIFI_REQ_DHCP_CONF.
/** Wi-Fi status variable. */
static volatile uint8 wifi_connected = 0;
...
...
...
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
case M2M_WIFI_RESP_CON_STATE_CHANGED: {
...
...
break;
}
case M2M_WIFI_REQ_DHCP_CONF: {
uint8 *pu8IPAddress = (uint8*) pvMsg;
wifi_connected = 1;
/* Turn LED0 on to declare that IP address received. */
port_pin_set_output_level(LED_0_PIN, false);
printf("m2m_wifi_state: M2M_WIFI_REQ_DHCP_CONF: IP is %u.%u.%u.%u\n",
pu8IPAddress[0], pu8IPAddress[1], pu8IPAddress[2], pu8IPAddress[3]);
/*TODO: add socket initialization here. */
break;
}
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Notice that the demo application will set the global wifi_connected to 1 to indicate
that association is complete and IP address is obtained. The global wifi_connected
will be reset to zero if connection is lost. Notice that LED0 will turn at this time.
Upon completion of this step, the code should look like the following:
/** Wi-Fi status variable. */
static volatile uint8 wifi_connected = 0;
...
...
...
static void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
{
/* TODO: Check for socket event here. */
}
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
case M2M_WIFI_RESP_CON_STATE_CHANGED: {
tstrM2mWifiStateChanged *pstrWifiState = (tstrM2mWifiStateChanged*) pvMsg;
if (pstrWifiState->u8CurrState == M2M_WIFI_CONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: CONNECTED");
m2m_wifi_request_dhcp_client();
}
else if(pstrWifiState->u8CurrState == M2M_WIFI_DISCONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: DISCONNECTED");
wifi_connected = 0;
m2m_wifi_connect((char *)DEMO_WLAN_SSID, sizeof(DEMO_WLAN_SSID),
DEMO_WLAN_AUTH, (char *)DEMO_WLAN_PSK, M2M_WIFI_CH_ALL);
}
break;
}
case M2M_WIFI_REQ_DHCP_CONF: {
uint8 *pu8IPAddress = (uint8*) pvMsg;
wifi_connected = 1;
/* Turn LED0 on to declare that IP address received. */
port_pin_set_output_level(LED_0_PIN, false);
printf("m2m_wifi_state: M2M_WIFI_REQ_DHCP_CONF: IP is %u.%u.%u.%u\n",
pu8IPAddress[0], pu8IPAddress[1], pu8IPAddress[2], pu8IPAddress[3]);
break;
}
default: {
break;
}
}
}
/**
* \brief Demo main routine.
*/
void demo_start(void)
{
tstrWifiInitParam param;
sint8 ret;
/* Initialize Wi-Fi parameters structure. */
param.pfAppWifiCb = m2m_wifi_state;
/* Initialize temperature sensor. */
at30tse_init();
/* Reset network controller */
nm_bsp_init();
/* Initialize Wi-Fi driver with data and Wi-Fi status callbacks. */
ret = m2m_wifi_init(&param);
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The association stage is done. In next section we will open sockets and start sending
and receiving data.
11. Open sockets and send transmit and receive data.
We should send data to and receive data from the Android application. Hence, we need to create two
UDP sockets; one as a server (for receiving: rx_socket) and one as a client (for sending: tx_socket).
The demo Android app shall be connected to the same local AP and broadcasts a message on the local
AP WLAN. All ATWINC3400 devices on the local WLAN receive the broadcast message. The message
contains s_msg_temp_report structure. The message contains the name of the device which should
receive the message. Each device matches the name member to a string DEMO_PRODUCT_NAME
before changing the LED state as provided in led member in s_msg_temp_report message.
In return, the device broadcasts two messages every 1 sec. on local AP WLAN, namely: keep alive
message t_msg_temp_keepalive and temperature report message t_msg_temp_report. Each device
provides its name in transmitted messages in name field as defined in DEMO_PRODUCT_NAME. The
t_msg_temp_keepalive message allows the demo Android app to discover the existence of
ATWINC3400 devices on local WLAN and displays a list of discovered devices, to the user. When the
user chooses to view temperature from a specific device, the Android app matches the received
t_msg_temp_report message name field to the name of the user selected device before plotting the
temperature value.
typedef struct s_msg_temp_keepalive {
uint8_t id0;
uint8_t id1;
uint8_t name[9];
uint8_t type;
} t_msg_temp_keepalive;
typedef struct s_msg_temp_report {
uint8_t id0;
uint8_t id1;
uint8_t name[9];
uint8_t led;
uint32_t temp;
} t_msg_temp_report;
Locate the definition of DEMO_PRODUCT_NAME in demo.h and modify it to a unique name
that you prefer. Notice that maximum name length is eight characters.
To get started with transmit and receive, add the following code to the demo application:
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/** RX and TX socket handlers. */
static SOCKET rx_socket = -1;
static SOCKET tx_socket = -1;
...
...
...
void demo_start(void)
{
...
...
...
while (1) {
/* Handle pending events from network controller. */
m2m_wifi_handle_events(NULL);
if (wifi_connected == M2M_WIFI_CONNECTED) {
/* Open server socket. */
if (rx_socket < 0) {
if ((rx_socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
puts("demo_start: failed to create RX UDP client socket error!");
continue;
}
bind(rx_socket, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
}
/* Open client socket. */
if (tx_socket < 0) {
if ((tx_socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
puts("demo_start: failed to create TX UDP client socket error!");
continue;
}
}
}
}
}
The above code open two sockets and attempts to bind on the UDP server socket. When bind is
complete, m2m_wifi_socket_handler() is called with an u8Msg = SOCKET_MSG_BIND success
indication. We need to add a handler for SOCKET_MSG_BIND inside m2m_wifi_socket_handler().
/** Receive buffer definition. */
#define TEST_BUFFER_SIZE 1460
static uint8 gau8SocketTestBuffer[TEST_BUFFER_SIZE];
/** RX
static
static
...
...
...
static
{
and TX socket handlers. */
SOCKET rx_socket = -1;
SOCKET tx_socket = -1;
void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
/* Check for socket event on RX socket. */
if (sock == rx_socket) {
if (u8Msg == SOCKET_MSG_BIND) {
tstrSocketBindMsg *pstrBind = (tstrSocketBindMsg *)pvMsg;
if (pstrBind && pstrBind->status == 0) {
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
}
else {
puts("m2m_wifi_socket_handler: bind error!");
}
}
}
}
After successful bind, the demo app will start receiving data from the UDP server. The demo app allocates a
static buffer gau8SocketTestBuffer to receive incoming data.
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Notice that recvfrom() is called after successful bind() callback.
The call to recvfrom() is non-blocking and execution will return again to application main loop. When data is
received, m2m_wifi_socket_handler() is called with an u8Msg = SOCKET_MSG_RECVFROM and pvMsg is a
pointer to tstrSocketRecvMsg structure.
/** RX
static
static
...
...
static
{
and TX socket handlers. */
SOCKET rx_socket = -1;
SOCKET tx_socket = -1;
void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
/* Check for socket event on RX socket. */
if (sock == rx_socket) {
if (u8Msg == SOCKET_MSG_BIND) {
...
...
else if (u8Msg == SOCKET_MSG_RECVFROM) {
tstrSocketRecvMsg *pstrRx = (tstrSocketRecvMsg *)pvMsg;
if (pstrRx->pu8Buffer && pstrRx->s16BufferSize) {
/* Check for server report and update led status if necessary. */
t_msg_temp_report report;
memcpy(&report, pstrRx->pu8Buffer, sizeof(t_msg_temp_report));
if (report.id0 == 0 && report.id1 == 2 &&
strstr((char *)report.name, DEMO_PRODUCT_NAME)) {
puts("wifi_nc_data_callback: received app message");
port_pin_set_output_level(LED_0_PIN, report.led ? true : false);
delay = 0;
}
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
} else {
if (pstrRx->s16BufferSize == SOCK_ERR_TIMEOUT) {
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
}
}
}
}
}
The structure tstrSocketRecvMsg provides information about the RX buffer pointer for current socket as well
as the received size. As explained previously, the received message contains a t_msg_temp_report structure
which contains LED on/off command to a specific device. The device changes the LED status only when the
received t_msg_temp_report .name[9] field matches its DEMO_PRODUCT_NAME.
12. Send a discovery frame and temperature information.
In order to send UDP packets every 1 sec., the application’s main loop keeps track of the current time in
milliseconds and waits for DEMO_REPORT_INTERVAL duration to elapse before sending the next packet. The
duration DEMO_REPORT_INTERVAL is defined in demo.h and set to 1000ms.
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Add the following code listing to your demo application:
/** Message format declarations. */
static t_msg_temp_keepalive msg_temp_keepalive = {
.id0 = 0, .id1 = 1, .name = DEMO_PRODUCT_NAME, .type = 2,
};
static t_msg_temp_report msg_temp_report = {
.id0 = 0, .id1 = 2, .name = DEMO_PRODUCT_NAME, .led = 0, .temp = 0,
};
void demo_start(void)
{
while (1) {
/* Handle pending events from network controller. */
m2m_wifi_handle_events(NULL);
if (wifi_connected == M2M_WIFI_CONNECTED
&& (ms_ticks - delay > DEMO_REPORT_INTERVAL)) {
/* Open server socket. */
if (rx_socket < 0) {
...
...
}
/* Open client socket. */
if (tx_socket < 0) {
...
...
}
/* Send client discovery frame. */
sendto(tx_socket, &msg_temp_keepalive, sizeof(t_msg_temp_keepalive), 0,
(struct sockaddr *)&addr, sizeof(addr));
/* Send client report. */
msg_temp_report.temp = (uint32_t)(at30tse_read_temperature() * 100);
msg_temp_report.led = !port_pin_get_output_level(LED_0_PIN);
ret = sendto(tx_socket, &msg_temp_report, sizeof(t_msg_temp_report), 0,
(struct sockaddr *)&addr, sizeof(addr));
if (ret == M2M_SUCCESS) {
puts("demo_start: sensor report sent");
} else {
puts("demo_start: failed to send status report error!");
}
}
}
}
The IoT temperature sensor application is now complete and you are ready to program the SAM D21 Xplained Pro board. Your final code should be like the following
listing:
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/**
*
* \file
*
* \brief Wi-Fi NMI temperature sensor demo.
*
* Copyright (c) 2014 Atmel Corporation. All rights reserved.
*
* \asf_license_start
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
*
this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
*
this list of conditions and the following disclaimer in the documentation
*
and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
*
from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
*
Atmel microcontroller product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
<string.h>
<ctype.h>
<stdio.h>
"asf.h"
"demo.h"
"bsp/include/nm_bsp.h"
"driver/include/m2m_wifi.h"
"socket/include/socket.h"
"conf_wifi_m2m.h"
/** Message format definitions. */
typedef struct s_msg_temp_keepalive {
uint8_t id0;
uint8_t id1;
uint8_t name[9];
uint8_t type;
} t_msg_temp_keepalive;
typedef struct s_msg_temp_report {
uint8_t id0;
uint8_t id1;
uint8_t name[9];
uint8_t led;
uint32_t temp;
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} t_msg_temp_report;
/** Message format declarations. */
static t_msg_temp_keepalive msg_temp_keepalive =
{
.id0 = 0,
.id1 = 1,
.name = DEMO_PRODUCT_NAME,
.type = 2,
};
static t_msg_temp_report msg_temp_report =
{
.id0 = 0,
.id1 = 2,
.name = DEMO_PRODUCT_NAME,
.led = 0,
.temp = 0,
};
/** Receive buffer definition. */
#define TEST_BUFFER_SIZE 1460
static uint8 gau8SocketTestBuffer[TEST_BUFFER_SIZE];
/** RX and TX socket handlers. */
static SOCKET rx_socket = -1;
static SOCKET tx_socket = -1;
/** Wi-Fi status variable. */
static volatile uint8 wifi_connected = 0;
/** Global counter delay for timer. */
static uint32_t delay = 0;
/** SysTick counter for non busy wait delay. */
extern uint32_t ms_ticks;
/**
* \brief Callback to get the Data from socket.
*
* \param[in] sock socket handler.
* \param[in] u8Msg socket event type. Possible values are:
* - SOCKET_MSG_BIND
* - SOCKET_MSG_LISTEN
* - SOCKET_MSG_ACCEPT
* - SOCKET_MSG_CONNECT
* - SOCKET_MSG_RECV
* - SOCKET_MSG_SEND
* - SOCKET_MSG_SENDTO
* - SOCKET_MSG_RECVFROM
* \param[in] pvMsg is a pointer to message structure. Existing types are:
* - tstrSocketBindMsg
* - tstrSocketListenMsg
* - tstrSocketAcceptMsg
* - tstrSocketConnectMsg
* - tstrSocketRecvMsg
*/
static void m2m_wifi_socket_handler(SOCKET sock, uint8 u8Msg, void *pvMsg)
{
/* Check for socket event on RX socket. */
if (sock == rx_socket) {
if (u8Msg == SOCKET_MSG_BIND) {
tstrSocketBindMsg *pstrBind = (tstrSocketBindMsg *)pvMsg;
if (pstrBind && pstrBind->status == 0) {
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
}
else {
puts("m2m_wifi_socket_handler: bind error!");
}
}
else if (u8Msg == SOCKET_MSG_RECVFROM) {
tstrSocketRecvMsg *pstrRx = (tstrSocketRecvMsg *)pvMsg;
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if (pstrRx->pu8Buffer && pstrRx->s16BufferSize) {
/* Check for server report and update led status if necessary. */
t_msg_temp_report report;
memcpy(&report, pstrRx->pu8Buffer, sizeof(t_msg_temp_report));
if (report.id0 == 0 && report.id1 == 2
&& strstr((char *)report.name, DEMO_PRODUCT_NAME)) {
puts("wifi_nc_data_callback: received app message");
port_pin_set_output_level(LED_0_PIN, report.led ? true : false);
delay = 0;
}
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
}
else {
if (pstrRx->s16BufferSize == SOCK_ERR_TIMEOUT) {
/* Prepare next buffer reception. */
recvfrom(sock, gau8SocketTestBuffer, TEST_BUFFER_SIZE, 0);
}
}
}
}
}
/**
* \brief Callback to get the Wi-Fi status update.
*
* \param[in] u8MsgType type of Wi-Fi notification. Possible types are:
* - [M2M_WIFI_RESP_CURRENT_RSSI](@ref M2M_WIFI_RESP_CURRENT_RSSI)
* - [M2M_WIFI_RESP_CON_STATE_CHANGED](@ref M2M_WIFI_RESP_CON_STATE_CHANGED)
* - [M2M_WIFI_RESP_CONNTION_STATE](@ref M2M_WIFI_RESP_CONNTION_STATE)
* - [M2M_WIFI_RESP_SCAN_DONE](@ref M2M_WIFI_RESP_SCAN_DONE)
* - [M2M_WIFI_RESP_SCAN_RESULT](@ref M2M_WIFI_RESP_SCAN_RESULT)
* - [M2M_WIFI_REQ_WPS](@ref M2M_WIFI_REQ_WPS)
* - [M2M_WIFI_RESP_IP_CONFIGURED](@ref M2M_WIFI_RESP_IP_CONFIGURED)
* - [M2M_WIFI_RESP_IP_CONFLICT](@ref M2M_WIFI_RESP_IP_CONFLICT)
* - [M2M_WIFI_RESP_P2P](@ref M2M_WIFI_RESP_P2P)
* - [M2M_WIFI_RESP_AP](@ref M2M_WIFI_RESP_AP)
* - [M2M_WIFI_RESP_CLIENT_INFO](@ref M2M_WIFI_RESP_CLIENT_INFO)
* \param[in] pvMsg A pointer to a buffer containing the notification parameters
* (if any). It should be casted to the correct data type corresponding to the
* notification type. Existing types are:
* - tstrM2mWifiStateChanged
* - tstrM2MWPSInfo
* - tstrM2MP2pResp
* - tstrM2MAPResp
* - tstrM2mScanDone
* - tstrM2mWifiscanResult
*/
static void m2m_wifi_state(uint8 u8MsgType, void *pvMsg)
{
switch (u8MsgType) {
case M2M_WIFI_RESP_CON_STATE_CHANGED: {
tstrM2mWifiStateChanged *pstrWifiState = (tstrM2mWifiStateChanged*) pvMsg;
if (pstrWifiState->u8CurrState == M2M_WIFI_CONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: CONNECTED");
m2m_wifi_request_dhcp_client();
}
else if(pstrWifiState->u8CurrState == M2M_WIFI_DISCONNECTED) {
puts("m2m_wifi_state: M2M_WIFI_RESP_CON_STATE_CHANGED: DISCONNECTED");
wifi_connected = 0;
m2m_wifi_connect((char *)DEMO_WLAN_SSID, sizeof(DEMO_WLAN_SSID),
DEMO_WLAN_AUTH, (char *)DEMO_WLAN_PSK, M2M_WIFI_CH_ALL);
}
break;
}
case M2M_WIFI_REQ_DHCP_CONF: {
uint8 *pu8IPAddress = (uint8*) pvMsg;
wifi_connected = 1;
/* Turn LED0 on to declare that IP address received. */
port_pin_set_output_level(LED_0_PIN, false);
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printf("m2m_wifi_state: M2M_WIFI_REQ_DHCP_CONF: IP is %u.%u.%u.%u\n",
pu8IPAddress[0], pu8IPAddress[1], pu8IPAddress[2], pu8IPAddress[3]);
break;
}
default: {
break;
}
}
}
/**
* \brief Sensor thread entry.
*
* \param[in] params unused parameter.
*/
void demo_start(void)
{
tstrWifiInitParam param;
struct sockaddr_in addr;
sint8 ret;
/* Initialize Wi-Fi parameters structure. */
param.pfAppWifiCb = m2m_wifi_state;
/* Initialize socket address structure. */
addr.sin_family
= AF_INET;
addr.sin_port = _htons(DEMO_SERVER_PORT);
addr.sin_addr.s_addr = 0xFFFFFFFF;
/* Turn LED0 off initially. */
port_pin_set_output_level(LED_0_PIN, true);
/* Initialize temperature sensor. */
at30tse_init();
/* Reset network controller */
nm_bsp_init();
/* Initialize Wi-Fi driver with data and Wi-Fi status callbacks. */
ret = m2m_wifi_init(&param);
if (M2M_SUCCESS != ret) {
puts("demo_start: nm_drv_init call error!");
while (1)
;
}
/* Initialize Socket module */
socketInit();
registerSocketCallback(m2m_wifi_socket_handler, NULL);
/* Connect to router. */
m2m_wifi_connect((char *)DEMO_WLAN_SSID, sizeof(DEMO_WLAN_SSID),
DEMO_WLAN_AUTH, (char *)DEMO_WLAN_PSK, M2M_WIFI_CH_ALL);
while (1) {
/* Handle pending events from network controller. */
m2m_wifi_handle_events(NULL);
if ((wifi_connected == 1) && (ms_ticks - delay > DEMO_REPORT_INTERVAL)) {
delay = ms_ticks;
/* Open server socket. */
if (rx_socket < 0) {
if ((rx_socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
puts("demo_start: failed to create RX UDP client socket error!");
continue;
}
bind(rx_socket, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
}
/* Open client socket. */
if (tx_socket < 0) {
if ((tx_socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
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puts("demo_start: failed to create TX UDP client socket error!");
continue;
}
}
/* Send client discovery frame. */
sendto(tx_socket, &msg_temp_keepalive, sizeof(t_msg_temp_keepalive), 0,
(struct sockaddr *)&addr, sizeof(addr));
/* Send client report. */
msg_temp_report.temp = (uint32_t)(at30tse_read_temperature() * 100);
msg_temp_report.led = !port_pin_get_output_level(LED_0_PIN);
ret = sendto(tx_socket, &msg_temp_report, sizeof(t_msg_temp_report), 0,
(struct sockaddr *)&addr, sizeof(addr));
if (ret == M2M_SUCCESS) {
puts("demo_start: sensor report sent");
} else {
puts("demo_start: failed to send status report error!");
}
}
}
}
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Build the solution (F7) and ensure you get no errors:
Program the SAM D21 Xplained Pro.

Connect the ATWINC3400 Wi-Fi extension and the I/O1 extension to the SAM D21 Xplained Pro as
displayed:

Connect the SAM D21 Xplained Pro board to your PC using DEBUG USB connector

Program the application by clicking on the Start Debugging and Break icon:
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
You will be asked to select your debug tool:

Select EDBG and SWD (Serial Wire Debug) as Interface:

Set SWD clock to 8MHz to speed up programming:

Click again on the Start Debugging and Break icon:

The application will be programmed in the SAM D21 embedded flash and breaks at main function. Click
on Continue to execute the application:
You may be asked to upgrade your EDBG firmware. If so, click on Upgrade:
Upgrade operation may take a few minutes, wait for the operation to complete.
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The IoT sensor application is now programmed and running.
Open the EDBG DEBUG USB serial COM port, with the following settings: 115200 bauds, 8-bit data, no parity,
one stop bit and no flow control.

Connect the Android device to the same SSID network than the ATWINC3400 Wi-Fi module

Open the Temperature sensor application on the Android device


Hit the “Start Scan” button
A “TempSensor” device (as defined in the DEMO_PRODUCT_NAME macro in demo.h file) appears

Hit the “TempSensor” entry from the list

The Android application now displays real-time temperature information from the SAM D21 Xplained Pro
board

Hit the “LED Toggle” button to toggle LED0 on the SAM D21 Xplained Pro board
Congratulations, you just built your first IoT sensor application.
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16
Host Interface Protocol
Communication between the user application and the ATWINC device is facilitated by driver software. This
driver implements the Host Interface Protocol and exposes an API to the application with various services. The
services are broadly in two categories; Wi-Fi device control and IP Socket. The Wi-Fi device control services
allow actions such as channel scanning, network identification, connection, and disconnection. The Socket
services allow data transfer once a connection has been established and are similar to BSD socket definitions.
The host driver implements services asynchronously. This means that when the application calls an API to
request a service action, the call is non-blocking and returns immediately, often before the action is completed.
Where appropriate, notification that an action has completed is provided in a subsequent message from the
ATWINC device to the Host, which is delivered to the application via a callback function. More generally, the
ATWINC firmware uses asynchronous events to signal the host driver of certain status changes. Asynchronous
operation is essential where functions (such as Wi-Fi connection) make take significant time.
When an API is called, a sequence of layers is activated formatting the request and arranging to transfer it to
the ATWINC device through the serial protocol.
Dealing with HIF messages in host MCU application is an advanced topic. For most
applications, it is recommended to use Wi-Fi and socket layers. Both layers hide the
complexity of the HIF APIs.
After the application sends request, the Host Driver (Wi-Fi/Socket layer) formats the request and sends it to the
HIF layer which then interrupts the ATWINC device announcing that a new request will be posted. Upon
receipt, the ATWINC firmware parses the request and starts the required operation.
Figure 16-1.
ATWINC Driver Layers
HOST MCU
Host Applicaton
Host Driver
Socket
Wi-Fi
HIF
Bus
BSP
Bus Wrapper
The Host Interface Layer is responsible for handling communication between the host MCU and the ATWINC
device. This includes Interrupt handling, DMA control, and management of communication logic between
firmware driver at host and ATWINC firmware.
The Request/Response sequence between the Host and the ATWINC chip is shown in Figure 16-2.
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Figure 16-2.
The Request/Response Sequence Diagram
WINC
DRIVER
Application
Wi-Fi/Socket
Layer
Host
Interface
WINC
FIRMWARE
Request
Format Request
Interrupt WINC
Write RQ to Memory
Tx Done Interrupt
Process
Request
Write
Response
to
Memory
Interrupt Host
Call appropriate handler
Read Response Data
Send Response to
Application Callback
function
16.1
Rx Done
Interrupt
Transfer Sequence Between HIF Layer and ATWINC Firmware
The following section shows the individual steps taken during a HIF frame transmit (HIF message to the
ATWINC) and a HIF frame receive (HIF message from the ATWINC).
16.1.1 Frame Transmit
Figure 16-3 shows the steps and states involved in sending a message from the host to the ATWINC device.
Figure 16-3.
Wake up
WINC device
(state 1)
HIF Frame Transmit to ATWINC
Interrupt
WINC device
(state 2)
Poll for DMA
Address
(state 3)
Write
Data
(state 4)
TX Done
Interrupt
(state 5)
Allow WINC
to sleep
(state 6)
Fail to allocate
memory
(error state)
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Step
Description
Step (1) Wake up the ATWINC device
Wakeup the device to be able to receive Host requests
Step (2) Interrupt the ATWINC device
Prepare and Set the HIF layer header to NMI_STATE_REG register (4bytes header describing the sent packet).
Set BIT [1] of WIFI_HOST_RCV_CTRL_2 register to raise an interrupt to
the ATWINC chip.
Step (3) Poll for DMA address
Wait until the ATWINC chip clears BIT [1] of WIFI_HOST_RCV_CTRL_2
register.
Get the DMA address (for the allocated memory) from register 0x150400.
Step (4) Write Data
Write the Data Blocks in sequence, the HIF header then the Control buffer
(if any) then the Data buffer (if any)
Step (5) TX Done Interrupt
Announce finishing writing the data by setting BIT [1] of
WIFI_HOST_RCV_CTRL_3 register
Step (6) Allow ATWINC device to sleep
Allow the ATWINC device to enter sleep mode again (if it wishes)
16.1.2 Frame Receive
Figure 16-4 shows the steps and states involved in sending a message from the ATWINC device to the host:
Figure 16-4.
HIF Frame Receive from ATWINC to Host
Wake up
WINC device
(state 1)
Check for
Interrupt
(state 2)
Clear
Interrupt
(state 3)
Read
Data
(state 4)
Process
Request
(state 5)
Step
92
Host Rx
done
(state 6)
Allow WINC
to sleep
(state 7)
Description
Step (1) Wake up the ATWINC device
Wakeup the device to be able to receive Host requests
Step (2) Check for Interrupt
Monitor BIT[0] of WIFI_HOST_RCV_CTRL_0 register.
Disable the host from receiving interrupts (until this one has been processed).
Step (3) Clear interrupt
Write zero to BIT[0] of WIFI_HOST_RCV_CTRL_0 register
Step (4) Read Data
Get the address of the data block from WIFI_HOST_RCV_CTRL_1 register.
Read Data block with size obtained from WIFI_HOST_RCV_CTRL_0 register BIT[13] <->BIT[2].
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Step
16.2
Description
Step (5) Process Request
Parse the HIF header at the start of the Data and forward the Data to the
appropriate registered Callback function
Step (6) HOST RX Done
Raise an interrupt for the chip to free the memory holding the data by setting BIT[1] of WIFI_HOST_RCV_CTRL_0 register.
Enable Host interrupt reception again.
Step (7) Allow ATWINC device to sleep
Allow the ATWINC device to enter sleep mode again (if it wishes).
HIF Message Header Structure
The HIF message is the data structure exchanged back and forth between the Host Interface and ATWINC
firmware. The HIF message header structure consists of three fields:
7
6
5
4
3
2
1
0
7
Group ID
6
5
4
3
2
1
0
Op Code
Payload Length
Payload
...
...
...
16.3

The Group ID (8-bits): A group ID is the category of the message. Valid categories are
M2M_REQ_GRP_WIFI, M2M_REQ_GRP_IP, M2M_REQ_GRP_HIF, M2M_REQ_GRP_OTA corresponding to Wi-Fi,
Socket, HIF, and OTA respectively. A group ID can be assigned one of the values enumerated in
tenuM2mReqGrp.

Op Code: (8-bit): A command number. Valid command number is a value enumerated in:
tenuM2mConfigCmd and tenuM2mStaCmd, tenuM2mApCmd, and tenuM2mP2pCmd corresponding to
configuration, STA mode, AP mode, and P2P mode commands. See the full list of commands in the
header file m2m_types.h.

Payload Length (16-bits): The payload length in bytes (does not include header).
HIF Layer APIs
The interface between the application and the driver will be done at the higher layer API interface (WiFi/Socket.) As previously explained, the driver upper layer uses a lower layer API to access the services of the
Host Interface Protocol. This section describes the Host Interface APIs that the upper layers use:
The following API functions are described:

hif_chip_wake

hif_chip_sleep

hif_register_cb

hif_isr

hif_receive

hif_send
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For all functions the return value is either M2M_SUCCESS (zero) in case of success or a negative value in case of
failure.
sint8 hif_chip_wake(void):
This function wakes the ATWINC chip from sleep mode using clock-less register access. It sets BIT[1]
of register 0x01 and sets the value of WAKE_REG register to WAKE_VALUE.
sint8 hif_chip_sleep(void):
This function enables sleep mode for the ATWINC chip by setting the WAKE_REG register to a value of
SLEEP_VALUE and clearing BIT[1] of register 0x01.
sint8 hif_register_cb(uint8 u8Grp,tpfHifCallBack fn):
This function set the callback function for different components (e.g. M2M_WIFI, M2M_HIF,
M2M_OTA, etc.). A callback is registered by upper layers to receive specific events of a specific
message group.
sint8 hif_isr(void):
This is the Host interface interrupt service routine. It handles interrupts generated by the ATWINC chip
and parses the HIF header to call back the appropriate handler.
sint8 hif_receive(uint32 u32Addr, uint8 *pu8Buf, uint16 u16Sz, uint8 isDone):
This function causes the Host driver to read data from the ATWINC chip. The location and length of the
data must be known in advance and specified. This will typically have been extracted from an earlier
part of a transaction.
sint8 hif_send(uint8 u8Gid,uint8 u8Opcode,uint8 *pu8CtrlBuf,uint16 u16CtrlBufSize,uint8
*pu8DataBuf,uint16 u16DataSize, uint16 16DataOffset):
This function causes the Host driver to send data to the ATWINC chip. The ATWINC chip will have
been prepared for reception according to the flow described in the previous section.
16.4
Scan Code Example
The following code example illustrates the Request/Response flow on a Wi-Fi Scan request. For more details
on the code examples, refer to [R04].

The application requests a Wi-Fi scan
{
m2m_wifi_request_scan(M2M_WIFI_CH_ALL);
}

The Host driver Wi-Fi layer formats the request and forward it to HIF (Host Interface) layer
sint8 m2m_wifi_request_scan(uint8 ch)
{
tstrM2MScan strtmp;
sint8 s8Ret = M2M_ERR_SCAN_IN_PROGRESS;
strtmp.u8ChNum = ch;
s8Ret = hif_send(M2M_REQ_GRP_WIFI, M2M_WIFI_REQ_SCAN, (uint8*)&strtmp,
sizeof(tstrM2MScan),NULL, 0,0);
return s8Ret;
}

The HIF layer sends the request to the ATWINC chip
sint8 hif_send(uint8 u8Gid,uint8 u8Opcode,uint8 *pu8CtrlBuf,uint16 u16CtrlBufSize,
uint8 *pu8DataBuf,uint16 u16DataSize, uint16 u16DataOffset)
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{
sint8 ret = M2M_ERR_SEND;
volatile tstrHifHdr strHif;
strHif.u8Opcode = u8Opcode&(~NBIT7);
strHif.u8Gid = u8Gid;
strHif.u16Length = M2M_HIF_HDR_OFFSET;
if(pu8DataBuf != NULL)
{
strHif.u16Length += u16DataOffset + u16DataSize;
}
else
{
strHif.u16Length += u16CtrlBufSize;
}
/* TX STEP (1) */
ret = hif_chip_wake();
if(ret == M2M_SUCCESS)
{
volatile uint32 reg, dma_addr = 0;
volatile uint16 cnt = 0;
reg = 0UL;
reg |= (uint32)u8Gid;
reg |= ((uint32)u8Opcode<<8);
reg |= ((uint32)strHif.u16Length<<16);
ret = nm_write_reg(NMI_STATE_REG,reg);
if(M2M_SUCCESS != ret) goto ERR1;
reg = 0;
/* TX STEP (2) */
reg |= (1<<1);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_2, reg);
if(M2M_SUCCESS != ret) goto ERR1;
dma_addr = 0;
for(cnt = 0; cnt < 1000; cnt ++)
{
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_2,(uint32 *)&reg);
if(ret != M2M_SUCCESS) break;
if (!(reg & 0x2))
{
/* TX STEP (3) */
ret = nm_read_reg_with_ret(0x150400,(uint32 *)&dma_addr);
if(ret != M2M_SUCCESS) {
/*in case of read error clear the dma address and return error*/
dma_addr = 0;
}
/*in case of success break */
break;
}
}
if (dma_addr != 0)
{
volatile uint32
u32CurrAddr;
u32CurrAddr = dma_addr;
strHif.u16Length=NM_BSP_B_L_16(strHif.u16Length);
/* TX STEP (4) */
ret = nm_write_block(u32CurrAddr, (uint8*)&strHif, M2M_HIF_HDR_OFFSET);
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if(M2M_SUCCESS != ret) goto ERR1;
u32CurrAddr += M2M_HIF_HDR_OFFSET;
if(pu8CtrlBuf != NULL)
{
ret = nm_write_block(u32CurrAddr, pu8CtrlBuf, u16CtrlBufSize);
if(M2M_SUCCESS != ret) goto ERR1;
u32CurrAddr += u16CtrlBufSize;
}
if(pu8DataBuf != NULL)
{
u32CurrAddr += (u16DataOffset - u16CtrlBufSize);
ret = nm_write_block(u32CurrAddr, pu8DataBuf, u16DataSize);
if(M2M_SUCCESS != ret) goto ERR1;
u32CurrAddr += u16DataSize;
}
reg = dma_addr << 2;
reg |= (1 << 1);
/* TX STEP (5) */
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_3, reg);
if(M2M_SUCCESS != ret) goto ERR1;
}
else
{
/* ERROR STATE */
M2M_DBG("Failed to alloc rx size\r");
ret = M2M_ERR_MEM_ALLOC;
goto ERR1;
}
}
else
{
M2M_ERR("(HIF)Fail to wakup the chip\n");
goto ERR1;
}
/* TX STEP (6) */
ret = hif_chip_sleep();
ERR1:
return ret;}

The ATWINC chip processes the request and interrupts the host after finishing the operation

The HIF layer then receives the response
static sint8 hif_isr(void)
{
sint8 ret = M2M_ERR_BUS_FAIL;
uint32 reg;
volatile tstrHifHdr strHif;
/* RX STEP (1) */
ret = hif_chip_wake();
if(ret == M2M_SUCCESS)
{
/* RX STEP (2) */
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0, &reg);
if(M2M_SUCCESS == ret)
{
/* New interrupt has been received */
if(reg & 0x1)
{
96
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uint16 size;
nm_bsp_interrupt_ctrl(0);
/*Clearing RX interrupt*/
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0,&reg);
if(ret != M2M_SUCCESS)goto ERR1;
reg &= ~(1<<0);
/* RX STEP (3) */
ret=nm_write_reg(WIFI_HOST_RCV_CTRL_0,reg);
if(ret != M2M_SUCCESS)goto ERR1;
/* read the rx size */
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0, &reg);
if(M2M_SUCCESS != ret)
{
M2M_ERR("(hif) WIFI_HOST_RCV_CTRL_0 bus fail\n");
nm_bsp_interrupt_ctrl(1);
goto ERR1;
}
gu8HifSizeDone = 0;
size = (uint16)((reg >> 2) & 0xfff);
if (size > 0) {
uint32 address = 0;
/**
start bus transfer
**/
/* RX STEP (4) */
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_1, &address);
if(M2M_SUCCESS != ret)
{
M2M_ERR("(hif) WIFI_HOST_RCV_CTRL_1 bus fail\n");
nm_bsp_interrupt_ctrl(1);
goto ERR1;
}
ret = nm_read_block(address, (uint8*)&strHif, sizeof(tstrHifHdr));
strHif.u16Length = NM_BSP_B_L_16(strHif.u16Length);
if(M2M_SUCCESS != ret)
{
M2M_ERR("(hif) address bus fail\n");
nm_bsp_interrupt_ctrl(1);
goto ERR1;
}
if(strHif.u16Length != size)
{
if((size - strHif.u16Length) > 4)
{
M2M_ERR("(hif) Corrupted packet Size = %u <L = %u, G = %u, OP
= %02X>\n",
size, strHif.u16Length, strHif.u8Gid, strHif.u8Opcode);
nm_bsp_interrupt_ctrl(1);
ret = M2M_ERR_BUS_FAIL;
goto ERR1;
}
}
/* RX STEP (5) */
if(M2M_REQ_GRP_WIFI == strHif.u8Gid)
{
if(pfWifiCb)
pfWifiCb(strHif.u8Opcode,strHif.u16Length - M2M_HIF_HDR_OFFSET,
address + M2M_HIF_HDR_OFFSET);
}
else if(M2M_REQ_GRP_IP == strHif.u8Gid)
{
if(pfIpCb)
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pfIpCb(strHif.u8Opcode,strHif.u16Length - M2M_HIF_HDR_OFFSET,
address + M2M_HIF_HDR_OFFSET);
}
else if(M2M_REQ_GRP_OTA == strHif.u8Gid)
{
if(pfOtaCb)
pfOtaCb(strHif.u8Opcode,strHif.u16Length - M2M_HIF_HDR_OFFSET,
address + M2M_HIF_HDR_OFFSET);
}
else
{
M2M_ERR("(hif) invalid group ID\n");
ret = M2M_ERR_BUS_FAIL;
goto ERR1;
}
/* RX STEP (6) */
if(!gu8HifSizeDone)
{
M2M_ERR("(hif) host app didn't set RX Done\n");
ret = hif_set_rx_done();
}
}
else
{
ret = M2M_ERR_RCV;
M2M_ERR("(hif) Wrong Size\n");
goto ERR1;
}
}
else
{
#ifndef WIN32
M2M_ERR("(hif) False interrupt %lx",reg);
#endif
}
}
else
{
M2M_ERR("(hif) Fail to Read interrupt reg\n");
goto ERR1;
}
}
else
{
M2M_ERR("(hif) FAIL to wakeup the chip\n");
goto ERR1;
}
/* RX STEP (7) */
ret = hif_chip_sleep();
ERR1:
return ret;
}

The appropriate handler is layer Wi-Fi (called from HIF layer)
{
98
static void m2m_wifi_cb(uint8 u8OpCode, uint16 u16DataSize, uint32 u32Addr)
// …code eliminated…
else if (u8OpCode == M2M_WIFI_RESP_SCAN_DONE)
{
tstrM2mScanDone strState;
gu8scanInProgress = 0;
if(hif_receive(u32Addr, (uint8*)&strState, sizeof(tstrM2mScanDone), 0) == M2M_SUCCESS)
{
gu8ChNum = strState.u8NumofCh;
if (gpfAppWifiCb)
gpfAppWifiCb(M2M_WIFI_RESP_SCAN_DONE, &strState);
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}
}
// …code eliminated…
}

The Wi-Fi layer sends the response to the application through its callback function
if (u8MsgType == M2M_WIFI_RESP_SCAN_DONE)
{
tstrM2mScanDone *pstrInfo = (tstrM2mScanDone*) pvMsg;
if(
(gu8IsWiFiConnected == M2M_WIFI_DISCONNECTED) &&
(gu8WPS == WPS_DISABLED) && (gu8Prov == PROV_DISABLED)
{
gu8Index = 0;
gu8Sleep = PS_WAKE;
if (pstrInfo->u8NumofCh >= 1)
{
m2m_wifi_req_scan_result(gu8Index);
gu8Index++;
}
else
{
m2m_wifi_request_scan(M2M_WIFI_CH_ALL);
}
}
}
)
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17
ATWINC SPI Protocol
The ATWINC main interface is SPI. The ATWINC device employs a protocol to allow exchange of formatted
binary messages between ATWINC firmware and host MCU application. The ATWINC protocol uses raw bytes
exchanged on SPI bus to form high level structures like requests and callbacks.
The ATWINC SPI protocol consists of three layers:

Layer 1: ATWINC SPI slave protocol, which allows the host MCU application to perform
register/memory read and write operation in the ATWINC3400 device using raw SPI data
exchange

Layer 2: Host MCU application uses the register and memory read and write capabilities to exchange
host interface frames with the ATWINC firmware. It also provides asynchronous callback from
the ATWINC firmware to the host MCU through interrupts and host interface RX frames. This
layer was discussed earlier in Chapter 16: Host Interface Protocol.

Layer 3: Allows the host MCU application to exchange high level messages (e.g. Wi-Fi scan, socket
connection, or TCP data received) with the ATWINC firmware to employ in the host MCU
application logic
Figure 17-1.
17.1
ATWINC SPI Protocol Layers
Host MCU
Application
•App Logic
Socket,
WLAN
Functions
•Init, scan,
connect, socket
WINC HIF
Frames
TX/RX
•hif_send,
•hif_receive
WINC SPI
Slave
Protocol
•write_reg
•read_reg
Host MCU
Raw SPI Bus
•SPI read/write
Introduction
The ATWINC SPI Protocol is implemented as a command-response transaction and assumes that one party is
the master and the other is the slave. The roles correspond to the master and slave devices on the SPI bus.
Each message has an identifier in the first byte indicating the type of message:

Command

Response

Data
In the case of Command and Data messages, the last byte is used as data integrity check.
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The format of Command and Response and Data frames is described in the following sections. The following
points apply:

There is a response for each command


Transmitted/received data is divided into packets with fixed size
For a write transaction (Slave is receiving data packets), the slave should reply by a response for each
data packet
For an RD transaction (Master is receiving data packets), the master doesn’t send response. If there is
an error, the master should request retransmission on the lost data packet.


Protection of commands and data packets by CRC is optional
17.1.1 Command Format
The following frame formation is used for commands where the host supports a DMA address of three bytes.
Payload Size
1 Byte
4 Bits
4 Bits
CMD/DATA Start
CMD type
Payload
1 Byte
CRC
10 Byte (max)
The first byte contains two fields:

The CMD/Data Start field indicates that this is a Command frame

The CMD type field specifies the command to be executed
The CMD type may be one of 15 commands:

DMA write

DMA read

Internal register write

Internal register read

Transaction termination

Repeat data Packet

DMA extended write

DMA extended read

DMA single-word write

DMA single-word read

Soft reset
The Payload field contains command specific data and its length depends on the CMD type.
The CRC field is optional and generally computed in software.
The Payload field can be one of four types each having a different length:

A: Three bytes

B: Five bytes

C: Six bytes

D: Seven bytes
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Type A commands include:

DMA single-word RD

internal register RD

Transaction termination command

Repeat Data PKT command

Soft reset command
Type B commands include:

DMA RD Transaction

DMA WR Transaction
Type C commands include:

DMA Extended RD transaction

DMA Extended WR transaction

Internal register WR
Type D commands include:

DMA single-word WR
Full details of the frame format fields are provided in the following table:
Field
102
Size
Description
CMD Start
4 bits
Command Start: 4’b1100
CMD Type
4 bits
Command type:
4’b0001: DMA write transaction
4’b0010: DMA read transaction
4’b0011: Internal register write
4’b0100: Internal register read
4’b0101: Transaction termination
4’b0110: Repeat data Packet command
4’b0111: DMA extended write transaction
4’b1000: DMA extended read transaction
4’b1001: DMA single-word write
4’b1010: DMA single-word read
4’b1111: soft reset command
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Payload
A: 3
B: 5
C: 6
D: 7
The Payload field may be of Type A, B, C, or D
Type A (length 3)
1- DMA single-word RD
Param: Read Address:
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
2- internal register RD
Param: Offset address (two bytes):
Payload bytes:
B0: OFFSET-ADDR[15:8]
B1: OFFSET-ADDR[7:0]
B2: 0
3- Transaction termination command
Param: none
Payload bytes:
B0: 0
B1: 0
B2: 0
4- Repeat Data PKT command
Param: none
Payload bytes:
B0: 0
B1: 0
B2: 0
5- Soft reset command
Param: none
Payload bytes:
B0: 0xFF
B1: 0xFF
B2: 0xFF
Type B (length 5)
1- DMA RD Transaction
Params:
DMA Start Address: 3 bytes
DMA count: 2 bytes
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
B3: COUNT[15:8]
B4: COUNT[7:0]
2- DMA WR Transaction
Params:
DMA Start Address: 3 bytes
DMA count: 2 bytes
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
B3: COUNT[15:8]
B4: COUNT[7:0]
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Field
Size
Description
Type C (length 6)
1- DMA Extended RD transaction
Params:
DMA Start Address: 3 bytes
DMA extended count: 3 bytes
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
B3: COUNT[23:16]
B4: COUNT[15:8]
B5: COUNT[7:0]
2- DMA Extended WR transaction
Params:
DMA Start Address: 3 bytes
DMA extended count: 3 bytes
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
B3: COUNT[23:16]
B4: COUNT[15:8]
B5: COUNT[7:0]
3- Internal register WR*
Params:
Offset address: 3 bytes
Write Data: 3 bytes
* “clocked or clockless registers”
Payload bytes:
B0: OFFSET-ADDR[15:8]
B1: OFFSET-ADDR [7:0]
B2: DATA[31:24]
B3: DATA [23:16]
B4: DATA [15:8]
B5: DATA [7:0]
Type D (length 7)
1- DMA single-word WR
Params:
Address: 3 bytes
DMA Data: 4 bytes
Payload bytes:
B0: ADDRESS[23:16]
B1: ADDRESS[15:8]
B2: ADDRESS[7:0]
B3: DATA[31:24]
B4: DATA [23:16]
B5: DATA [15:8]
B6: DATA [7:0]
CRC7
104
1 byte
Optional data integrity field comprising two subfields:
bit 0: fixed value ‘1’
bits 1-7: 7 bit CRC value computed using polynomial G(x)
= X^7 + X^3 + 1 with seed value: 0x7F
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The following table summarizes the different commands according to the payload type (DMA address = 3bytes):
Payload type
Payload size
Command packet size
“with CRC”
Commands
Type A
3-Bytes
5-Bytes
1- DMA Single-Word Read
2- Internal Register Read
3- Transaction Termination
4- Repeat Data Packet
5- Soft Reset
Type B
5-Bytes
7-Bytes
1- DMA Read
2- DMA Write
Type C
6-Bytes
8-Bytes
1- DMA Extended Read
2- DMA Extended Write
3- Internal Register Write
Type D
7-Bytes
9-Bytes
1- DMA Single-Word Write
17.1.2 Response Format
The following frame formation is used for responses sent by the ATWINC device as the result of receiving a
Command or certain Data frames. The Response message has a fixed length of two bytes.
1 Byte
1 Byte
4 Bits
4 Bits
RES/DATA Start
RES Type
STATE
2 Byte
The first byte contains two 4-bit fields which identify the response message and the response type.
The second byte indicates the status of the ATWINC after receiving and, where possible, executing the
command/data. This byte contains two sub fields:

B0-B3: Error state

B4-B7: DMA state
States that may be indicated are:


DMA state:
–
DMA ready for any transaction
–
DMA engine is busy
Error state:
–
No error
–
Unsupported command
–
Receiving unexpected data packet
–
Command CRC7 error
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Field
Size
Description
Res Start
4 bits
Response Start : 4’b1100
Response Type
4 bits
If the response packet is for Command:

Contains of copy of the Command Type field in the
Command.
If the response packet is for received Data Packet:

4’b0001: first data packet is received

4’b0010: Receiving data packets

4’b0011: last data packet is received

4’b1111: Reserved value
State
1 byte
This field is divided into two subfields:
State
DMA State
Error State
4 Bits
4 bits
DMA State :

4’b0000: DMA ready for any transaction

4’b0001: DMA engine is busy
Error State:

4’b0000: No error

4’b0001: Unsupported command

4’b0010: Receiving unexpected data packet

4’b0011: Command CRC7 error

4’b0100: Data CRC16 error

4’b0101: Internal general error
17.1.3 Data Packet Format
The Data Packet Format is used in either direction (master to slave or slave to master) to transfer opaque data.
A Command frame is used either to inform the slave that a data packet is about to be sent or to request the
slave to send a data packet to the master. In the case of master to slave, the slave sends a response after the
command and each subsequent data frame. The format of a data packet is shown below.
DATA Start
Packet Order
4 Bits
4 Bits
1 Byte
Data Bytes
CRC
DATA_PACKET_SIZE
2 Byte
To support DMA hardware a large data transfer may be fragmented into multiple smaller Data Packets. This is
controlled by the value of DATA_PACKET_SIZE which is agreed between the master and slave in software
and is a fixed value such as 256B, 512B, 1KB (default), 2KB, 4KB, or 8KB. If a transfer has a length m which
exceeds DATA_PACKET_SIZE the sender must split into n frames where frames 1..n-1 will be length
DATA_PACKET_SIZE and frame n will be length:
(m – (n-1)* DATA_PACKET_SIZE).This is shown diagrammatically below:

If DMA count <= DATA_PACKET_SIZE
The data packet is “DATA_Header + DMA count +optional CRC16“, i.e. no padding.
DATA
Header
106
Remaining data
CRC
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
If DMA count > DATA_PACKET_SIZE
DMA Count
DATA
Header
DATA_PKT_SIZE
CRC16
DATA
Header
DATA_PKT_SIZE
CRC16
DATA
Header
Remaining
data
CRC16
If remaining data < DATA_PACKET_SIZE, the last data packet is:
“DATA_Header + remaining data + optional CRC16 “, i.e. no padding.
The frame fields are describe in detail in the following table:
Field
Size
Description
Data Start
4 bits
4’b1111 (Default)
(Can be changed to any value by programming
DATA_START_CTRL register)
Packet Order
4 bits
4’b0001: First packet in this transaction
4’b0010: Neither the first or the last packet in this transaction
4’b0011: Last packet in this transaction
4’b1111: Reserved
Data Bytes
DATA_PACKET_SIZE
User data
CRC16
2 bytes
Optional data integrity field comprising a 16-bit CRC value
encoded in two bytes. The most significant eight bits are
transmitted first in the frame.
The CRC16 value is computed on data bytes only based on
the polynomial:
G(x) = X^16 + X^12 + X^5 + 1, seed value: 0xFFFF
17.1.4 Error Recovery Mechanism
Error type
Recovery mechanism
Master:
CRC error in command
CRC error in received
data
No response is received
from slave
1.
Error response received from slave.
2.
Retransmit the command.
1.
Issue a repeat command for the data packet that has a CRC error.
2.
Slave sends a response to the previous command.
3.
Slave keeps the start DMA address of the previous data packet, so it can retransmit it.
4.
Receive the data packet again.
 Synchronization is lost between master and slave
 The worst case is when slave is in receiving data state
 Solution: master should wait for maximum DATA_PACKET_SIZE period, then
generate a soft reset command
Unexpected response
Retransmit the command
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Error type
Recovery mechanism
TX/RX Data count error
No response to soft reset
command
Retransmit the command
 Transmit all ones till master receives a response of all ones from the slave
 Then deactivate the output data line
Slave:
Unsupported command

Send response with error

Returns to command monitor state
Receive command CRC
error

Send response with error

waits for command retransmission
Received data CRC error

Send response with error

wait for retransmission of the data packet
Internal general error

The master should soft reset the slave
TX/RX Data count error

Only the master can detect this error

Slave operates with the data count received till the count finishes or the master
terminates the transaction

In both cases the master should retry the command from the beginning
No response to soft reset
command
General NOTE
1.
First received 4’b1001, it decides data start.
2.
Then received packet order 4’b1111 that is reserved value.
3.
Then monitors for 7 bytes all ones to decide Soft Reset action.
4.
The slave should activate the output data line.
5.
Waits for deactivation for the received line.
6.
The slave then deactivates the output data line and returns to the CMD/DATA start
monitor state.

The slave should monitor the received line for command reception in any time

When a CMD start is detected, the slave will receive eight bytes, then return again
to the command reception state

When the slave is transmitting data, it should also monitor for command reception

When the slave is receiving data, it will monitor for command reception between the
data packets

Therefore issuing a soft reset command, should be detected in all cases
17.1.5 Clockless Registers Access
Clockless register access allows a host device to access registers on the ATWINC device while it is held in a
reset state. This type of access can only be done using the “internal register read” and “internal register write”
commands. For clockless access, bit 15 of the Offset_addr in the command should be ‘1’ to differentiate
between clockless and clocked access mode.
For clock-less register write: - the protocol master should wait for the response as shown here:
‘0’
8'hC3
1 Byte
‘0’
Offset_addr[15]
=1'b1
Offset_addr[14:0]
= clkless_addr
2 Byte
Four bytes of data
{ CRC7,1'b1 }
‘0’
4 Byte
1 Byte
‘0’
‘0’
Response
2 Byte
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For clock-less register read: - according to the interface, the protocol slave may not send CRC16. One or two
byte padding depends on three or four byte DMA addresses.
‘0’
Offset_addr[15]
=1'b1
8'hC3
1 Byte
Offset_addr[14:0]
= clkless_addr
2 Byte
One or two
byte padding
{ CRC7,1'b1 }
1 or 2 Byte
1 Byte
‘0’
Response
‘0’
2 Byte
17.2
Data Hdr
Clk-less
reg data
‘0’
1 Byte
Message Flow for Basic Transactions
This section shows the essential message exchanges and timings associated with the following commands:

Read Single Word

Read Internal Register (clockless)

Read Block

Write Single Word

Write Internal Register (clockless)

Write Bock
17.2.1 Read Single Word
CMD_RES Period
1 byte
‘0’
Cmd Hdr:
Read Single Word
4 bytes
Address / CRC
‘0’
‘0’
1 byte
1 byte
1 byte
Rsp Hdr
STATE
DATA Start
1 byte
1 byte
1 byte
Rsp Hdr
STATE
DATA Start
4 bytes
DATA
‘0’
17.2.2 Read Internal Register (for clockless registers)
CMD_RES Period
‘0’
‘0’
1 byte
2 bytes
Cmd Hdr:
Read Internal Register
Offset Addr
2 bytes
16‘d0
‘0’
4 bytes
DATA
‘0’
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17.2.3 Read Block
Normal transaction:
Master: Issues a DMA read transaction and waits for a response.
Slave:
Sends a response after CMD_RES_PERIOD.
Master: Waits for a data packet start.
Slave:
Sends the data packets, separated by DATA_DATA_PERIOD 5 where DATA_DATA_PERIOD is
controlled by software and has one of these values:
NO_DELAY (default), 4_BYTE_PERIOD, 8_BYTE_PERIOD, and 16_BYTE_PERIOD.
Slave:
Continues sending till the count ends.
Master: Receive data packets. No response is sent for data packets but a termination/retransmit command
may be sent if there is an error.
The message sequence for this case is shown below:
CMD_RES Period
DATA_DATA Period
1 byte
‘0’
Cmd Hdr:
Data Read
6 bytes
‘0’
Address, Count, crc
‘0’
1 byte
1 byte
1 byte
Rsp Hdr
STATE
DATA Hdr
2 byte
Fixed size
DATA
1 byte
‘0’
‘0’ CRC16
Fixed size
DAT Header
DATA
2 byte
‘0’
‘0’ CRC16
Termination command is issued:
Master: Can issue a termination command at any time during the transaction.
Master: Should monitor for RES_START after CMD_RESP_PERIOD.
Slave:
Should cut off the current running data packet “if any“.
Slave:
Should respond to the termination command after CMD_RESP_PERIOD from the end of the
termination command packet.
DATA_DATA Period
‘0’
Cmd Hdr:
Data Read
Address, Count, crc
Cmd Hdr:
STOP command
‘0’
1 Byte
‘0’
CMD_RESP Period
Rsp Hdr
STATE
DAT Header
Fixed size
DATA
2 Byte
‘0’ CRC16
1 Byte
‘0’
DATA Hdr
Fixed size
DATA
‘0’
2 Byte
‘0’ CRC16
‘0’
Rsp Hdr
STATE
‘0’
Actually the period between data packets is “DATA_DATA_PERIOD + DMA access time.” The master should monitor for DATA_START
directly after DATA_DATA_PERIOD
5
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Repeat command is issued:
1.
Master: Can issue a repeat command at any time during the transaction.
2.
Master: Should monitor for RES_START after CMD_RESP_PERIOD.
3.
Slave:
Should cut off the current running data packet, if any.
4.
Slave:
Should respond to the repeat command after CMD_RESP_PERIOD from the end of the repeat
command packet.
5.
Slave:
Resends the data packet that has an error then continues the transaction as normal.
‘0
’
‘0
’
Read
Command
‘0
’
Response
CMD_RESP Period
Repeat
Command
DATA Packet 1
‘0
’
DATA Packet 2
“error”
‘0
’
DATA Packet 3
“cut off”
Response
DATA Packet 3
DATA Packet 2
17.2.4 Write Single Word
1.
Master:
Issues DMA single-word write command, including the data.
2.
Slave:
Takes the data and sends a command response.
CMD_RES Period
1 byte
‘0’
Cmd Hdr:
Single Word Write
8 bytes
‘0’
Address, Data, CRC
Response
Hdr
‘0’
STATE
‘0’
17.2.5 Write Internal Register (for clockless registers)
1.
Master:
Issues an internal register write command, including the data.
2.
Slave:
Takes the data and sends a command response.
CMD_RES Period
‘0’
‘0’
1 byte
7 bytes
Cmd Hdr:
Internal Word Write
Offset Addr, Data, CRC
‘0’
Rsp Hdr
STATE
‘0’
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17.2.6 Write Block
Case 1: Master waits for a command response:
1.
Master:
Issues a DMA write command and waits for a response.
2.
Slave:
Sends response after CMD_RES_PERIOD.
3.
Master:
Sends the data packets after receiving response.
4.
Slave:
Sends a response packet for each data packet received after DATA_RES_PERIOD.
5.
Master:
Does not wait for the data response before sending the following data packet notes:
CMD_RES_PERIOD is controlled by SW taking one of the values:
NO_DELAY (default), 1_BYTE_PERIOD, 2_BYTE_PERIOD and 3_BYTE_PERIOD
The master should monitor for RES_START after CMD_RES_PERIOD
DATA_RES_PERIOD is controlled by SW taking one of the values:
NO_DELAY (default), 1_BYTE_PERIOD, 2_BYTE_PERIOD and 3_BYTE_PERIOD
DATA_RES Period
CMD_RES Period
1 byte
‘0’
Cmd Hdr:
Write Command
AddresS, Count, CRC
‘0’
DATA Hdr
‘0’
Rsp Hdr
Fixed size
DATA
2 byte
1 byte
CRC16
DATA Hdr
‘0’
STATE
Fixed size
Rsp Hdr
DATA
2 byte
1 byte
CRC16
DATA Hdr
‘0’
STATE
Fixed size
Rsp Hdr
DATA
2 byte
‘0’
CRC16
‘0’
STATE
Case 2: Master does not wait for a command response:
1.
Master: Sends the data packets directly after the command but it still monitors for a command
response after CMD_RESP_PERIOD.
2.
Master: Retransmits the data packets if there is an error in the command.
DATA_RES Period
CMD_RES Period
1 byte
‘0’
Cmd Hdr:
Write Command
Address, count, CRC
DATA Hdr
‘0’
17.3
Fixed size
DATA
Response
2 byte
1 byte
CRC16
DATA Hdr
‘0’
Fixed size
DATA
Data Response
2 byte
1 byte
CRC16
DATA Hdr
‘0’
Fixed size
DATA
Data Response
2 byte
CRC16
‘0’
‘0’
SPI Level Protocol Example
In order to illustrate how ATWINC SPI protocol works, SPI Bytes from the scan request example were dumped
and the sequence is described below.
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17.3.1 TX (Send Request)
First step in hif_send() API is to wake up the chip:
sint8 nm_clkless_wake(void)
{
ret = nm_read_reg_with_ret(0x1, &reg);
/* Set bit 1 */
ret = nm_write_reg(0x1, reg | (1 << 1));
// Check the clock status
ret = nm_read_reg_with_ret(clk_status_reg_adr, &clk_status_reg);
// Tell Firmware that Host waked up the chip
ret = nm_write_reg(WAKE_REG, WAKE_VALUE);
return ret;
}
Command
CMD_INTERNAL_READ: 0xC4
/* internal register read */
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
/* address = 0x01 */
/* clockless register */
BYTE [2] = address;
BYTE [3] = 0x00;
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
Then the ATWINC chip sends the value of the register 0x01 which equals 0x01.
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Command
CMD_INTERNAL_WRITE:
C3
BYTE [0] = CMD_INTERNAL_WRITE
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = u32data >> 24;
BYTE [4] = u32data >> 16;
BYTE [5] = u32data >> 8;
BYTE [6] = u32data;
/*
/*
internal register write */
/*
address = 0x01
clockless register
*/
/*
Data = 0x03
*/
*/
ATWINC acknowledges the command by sending two bytes [C3] [0].
Command
CMD_INTERNAL_READ:
0xC4
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = 0x00;
/*
internal register read
*/
/*
/*
*/
address = 0x0F
clockless register
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
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*/
Then ATWINC chip sends the value of the register 0x01 which equals 0x07.
Command
CMD_SINGLE_WRITE:0XC9
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
/* single word write
*/
/* WAKE_REG address = 0x1074 */
/* WAKE_VALUE Data = 0x5678 */
The chip acknowledges the command by sending two bytes [C9] [0].
At this point, HIF finishes executing the clockless wakeup of the ATWINC chip.
The HIF layer Prepares and Sets the HIF layer header to NMI_STATE_REG register (4 | 8 Byte header
describing the packet to be sent).
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Set BIT [1] of WIFI_HOST_RCV_CTRL_2 register to raise an interrupt to the chip.
sint8 hif_send(uint8 u8Gid,uint8 u8Opcode,uint8 *pu8CtrlBuf,uint16 u16CtrlBufSize,
uint8 *pu8DataBuf,uint16 u16DataSize, uint16 u16DataOffset)
{
volatile tstrHifHdr strHif;
volatile uint32 reg;
strHif.u8Opcode
= u8Opcode&(~NBIT7);
strHif.u8Gid
= u8Gid;
strHif.u16Length
= M2M_HIF_HDR_OFFSET;
strHif.u16Length += u16CtrlBufSize;
ret = nm_clkless_wake();
reg = 0UL;
reg |= (uint32)u8Gid;
reg |= ((uint32)u8Opcode<<8);
reg |= ((uint32)strHif.u16Length<<16);
ret = nm_write_reg(NMI_STATE_REG,reg);
reg = 0;
reg |= (1<<1);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_2, reg);
Command
CMD_SINGLE_WRITE:0XC9
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
M2M_WIFI_REQ_SET_SCAN_REGION */
BYTE [7] = u32data;
/* single word write */
/* NMI_STATE_REG address = 0x180c */
/* Data = 0x000C3001 */
/* 0x0C is the length and equals 12
/* 0x30 is the Opcode =
*/
/* 0x01 is the Group ID = M2M_REQ_GRP_WIFI
*/
ATWINC acknowledges the command by sending two bytes [C9] [0].
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Command
CMD_SINGLE_WRITE:0XC9 /*
single word write */
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16; /*
WIFI_HOST_RCV_CTRL_2address = 0x1087*/
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24; /*
Data = 0x02 */
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
ATWINC acknowledges the command by sending two bytes [C9] [0].
Then HIF polls for DMA address.
for (cnt = 0; cnt < 1000; cnt ++)
{
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_2,(uint32 *)&reg);
if(ret != M2M_SUCCESS) break;
if (!(reg & 0x2))
{
ret = nm_read_reg_with_ret(0x150400,(uint32 *)&dma_addr);
/*in case of success break */
break;
}
}
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read */
/* WIFI_HOST_RCV_CTRL_2 address = 0x1078 */
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ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip send the value of the register 0x1078 which equals 0x00.
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read */
/* address = 0x1504 */
ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
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Then the ATWINC chip send the value of the register 0x1504 which equals 0x037AA0.
ATWINC writes the HIF header to the DMA memory address.
u32CurrAddr = dma_addr;
strHif.u16Length=NM_BSP_B_L_16(strHif.u16Length);
ret = nm_write_block(u32CurrAddr, (uint8*)&strHif, M2M_HIF_HDR_OFFSET);
Command
CMD_DMA_EXT_WRITE:
0xC7
BYTE [0] = CMD_DMA_EXT_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = size >> 16;
BYTE [5] = size >> 8;
BYTE [6] = size;
/* DMA extended write */
/* address = 0x037AA0 */
/* size = 0x08
*/
ATWINC acknowledges the command by sending three bytes [C7] [0] [F3].
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The HIF layer writes the Data.
HIF writes the Control Buffer data (part of the framing of the request).
if (pu8CtrlBuf != NULL)
{
ret = nm_write_block(u32CurrAddr, pu8CtrlBuf, u16CtrlBufSize);
if(M2M_SUCCESS != ret) goto ERR1;
u32CurrAddr += u16CtrlBufSize;
}
Command
120
CMD_DMA_EXT_WRITE:
0xC7
BYTE [0] = CMD_DMA_EXT_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = size >> 16;
BYTE [5] = size >> 8;
BYTE [6] = size;
/* DMA extended write */
/* address = 0x037AA8 */
/* size = 0x04
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*/
ATWINC acknowledges the command by sending three bytes [C7] [0] [F3].
HIF layer writes the Data.
Finally, HIF finished writing the request data to memory and is going to interrupt the chip announcing that host
TX is done.
reg = dma_addr << 2;
reg |= (1 << 1);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_3, reg);
Command
CMD_SINGLE_WRITE:0XC9
/* single word write */
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
/* WIFI_HOST_RCV_CTRL_3 address = 0x106C */
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
/* Data = 0x000DEA82 */
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
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ATWINC acknowledges the command by sending two bytes [C9] [0].
HIF layer allows the chip to enter sleep mode again.
sint8 hif_chip_sleep(void)
{
sint8 ret = M2M_SUCCESS;
uint32 reg = 0;
ret = nm_write_reg(WAKE_REG, SLEEP_VALUE);
/* Clear bit 1 */
ret = nm_read_reg_with_ret(0x1, &reg);
if(reg&0x2)
{
reg &=~(1 << 1);
ret = nm_write_reg(0x1, reg);
}
}
Command
122
CMD_SINGLE_WRITE:0XC9
/* single word write */
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
/* WAKE_REG address = 0x1074 */
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
/* SLEEP_VALUE Data = 0x4321 */
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
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ATWINC acknowledges the command by sending two bytes [C9] [0].
Command
CMD_INTERNAL_READ: 0xC4
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = 0x00;
/* internal register read
*/
/* address = 0x01
*/
/* clockless register
*/
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
Then the ATWINC chip sends the value of the register 0x01 which equals 0x03.
Command
CMD_INTERNAL_WRITE: C3
BYTE [0] = CMD_INTERNAL_WRITE
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
/* internal register write
*/
/* address = 0x01
*/
/* clockless register
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BYTE
BYTE
BYTE
BYTE
[3]
[4]
[5]
[6]
=
=
=
=
u32data >> 24;
u32data >> 16;
u32data >> 8;
u32data;
/* Data = 0x01
*/
The ATWINC chip acknowledges the command by sending two bytes [C3] [0].
At this point, the HIF layer has finished posting the scan Wi-Fi request to the ATWINC chip and the request is
being processed by the chip.
17.3.2 RX (Receive Response)
After finishing the required operation (scan Wi-Fi) the ATWINC will interrupt the Host announcing that the
request has been processed.
Host will handle this interrupt to receive the response.
First step in hif_isr ( ) is to wake up the ATWINC chip.
sint8 nm_clkless_wake(void)
{
ret = nm_read_reg_with_ret(0x1, &reg);
/* Set bit 1 */
ret = nm_write_reg(0x1, reg | (1 << 1));
// Check the clock status
ret = nm_read_reg_with_ret(clk_status_reg_adr, &clk_status_reg);
// Tell Firmware that Host waked up the chip
ret = nm_write_reg(WAKE_REG, WAKE_VALUE);
return ret;
}
Command
124
CMD_INTERNAL_READ: 0xC4
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
/* internal register read */
/* address = 0x01 */
/* clockless register */
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BYTE [3] = 0x00;
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
Then the ATWINC chip sends the value of the register 0x01 which equals 0x01.
Command
CMD_INTERNAL_WRITE: C3
BYTE [0] = CMD_INTERNAL_WRITE
BYTE [1] = address >> 8;
/*
internal register write */
/*
address = 0x01
/*
clockless register
*/
BYTE
BYTE
BYTE
BYTE
BYTE
BYTE
[1]
[2]
[3]
[4]
[5]
[6]
|= (1 << 7);
= address;
= u32data >> 24;
= u32data >> 16;
= u32data >> 8;
= u32data;
/*
Data = 0x03
*/
*/
ATWINC acknowledges the command by sending two bytes [C3] [0].
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Command
CMD_INTERNAL_READ: 0xC4
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
/*
internal register read
*/
/*
address = 0x0F
/*
clockless register
*/
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = 0x00;
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
Then the ATWINC chip sends the value of the register 0x01 which equals 0x07.
Command
126
CMD_SINGLE_WRITE:0XC9
/* single word write */
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
/* WAKE_REG address = 0x1074 */
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
/* WAKE_VALUE Data = 0x5678 */
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
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*/
The chip acknowledges the command by sending two bytes [C9] [0].
Read register WIFI_HOST_RCV_CTRL_0 to check if there is new interrupt, and if so, clear it (as it will be
handled now).
static sint8 hif_isr(void)
{
sint8 ret ;
uint32 reg;
volatile tstrHifHdr strHif;
ret = hif_chip_wake();
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0, &reg);
if(reg & 0x1)
/* New interrupt has been received */
{
uint16 size;
/*Clearing RX interrupt*/
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0,&reg);
reg &= ~(1<<0);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_0,reg);
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
*/
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
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ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1070 which equals 0x31.
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
128
*/
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Then the ATWINC chip sends the value of the register 0x1070 which equals 0x31.
Clear the ATWINC Interrupt.
Command
CMD_SINGLE_WRITE:0XC9
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
/* single word write */
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
/* Data = 0x30 */
The chip acknowledges the command by sending two bytes [C9] [0].
Then HIF reads the data size.
/* read the rx size */
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0, &reg);
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Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
*/
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1070 which equals 0x30.
HIF reads hif header address.
/** start bus transfer**/
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_1, &address);
Command
130
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read */
/* WIFI_HOST_RCV_CTRL_1 address = 0x1084 */
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ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1078 which equals 0x037AB0.
HIF reads the hif header data (as a block).
ret = nm_read_block(address, (uint8*)&strHif, sizeof(tstrHifHdr));
Command
CMD_DMA_EXT_READ:
C8
BYTE [0] = CMD_DMA_EXT_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = size >> 16;
BYTE [5] = size >>;
BYTE [6] = size;
/* dma extended read */
/* address = 0x037AB0*/
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ATWINC acknowledges the command by sending three bytes [C8] [0] [F3].
ATWINC sends the data block (four bytes).
HIF then calls the appropriate handler according to the hif header received which tries to receive the Response
data payload. (Note that hif_receive ( ) obtains some data again for checks.)
sint8 hif_receive(uint32 u32Addr, uint8 *pu8Buf, uint16 u16Sz, uint8 isDone)
{
uint32 address, reg;
uint16 size;
sint8 ret = M2M_SUCCESS;
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0,&reg);
size = (uint16)((reg >> 2) & 0xfff);
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_1,&address);
/* Receive the payload */
ret = nm_read_block(u32Addr, pu8Buf, u16Sz);
}
Command
132
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
*/
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
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ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1070 which equals 0x30.
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
*/
/* WIFI_HOST_RCV_CTRL_1 address = 0x1084 */
ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1078 which equals 0x037AB0.
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Command
CMD_DMA_EXT_READ:
C8
BYTE [0] = CMD_DMA_EXT_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = size >> 16;
BYTE [5] = size >>;
BYTE [6] = size;
/* dma extended read */
/* address = 0x037AB8*/
ATWINC acknowledges the command by sending three bytes [C8] [0] [F3].
ATWINC sends the data block (four bytes).
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Now, after HIF layer received the response, it interrupts the chip to announce host RX is done.
static sint8 hif_set_rx_done(void)
{
uint32 reg;
sint8 ret = M2M_SUCCESS;
ret = nm_read_reg_with_ret(WIFI_HOST_RCV_CTRL_0,&reg);
/* Set RX Done */
reg |= (1<<1);
ret = nm_write_reg(WIFI_HOST_RCV_CTRL_0,reg);
}
Command
CMD_SINGLE_READ:
0xCA
BYTE [0] = CMD_SINGLE_READ
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
/* single word (4 bytes) read
*/
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070 */
ATWINC acknowledges the command by sending three bytes [CA] [0] [F3].
Then the ATWINC chip sends the value of the register 0x1070 which equals 0x30.
Command
CMD_SINGLE_WRITE:0XC9
/* single word write */
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
/* WIFI_HOST_RCV_CTRL_0 address = 0x1070
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
/* Data = 0x32*/
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
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The chip acknowledges the command by sending two bytes [C9] [0].
The HIF layer allows the chip to enter sleep mode again.
sint8 hif_chip_sleep(void)
{
sint8 ret = M2M_SUCCESS;
uint32 reg = 0;
ret = nm_write_reg(WAKE_REG, SLEEP_VALUE);
/* Clear bit 1 */
ret = nm_read_reg_with_ret(0x1, &reg);
if(reg&0x2)
{
reg &=~(1 << 1);
ret = nm_write_reg(0x1, reg);
}
}
Command
136
CMD_SINGLE_WRITE:0XC9
BYTE [0] = CMD_SINGLE_WRITE
BYTE [1] = address >> 16;
BYTE [2] = address >> 8;
BYTE [3] = address;
BYTE [4] = u32data >> 24;
BYTE [5] = u32data >> 16;
BYTE [6] = u32data >> 8;
BYTE [7] = u32data;
/* single word write
*/
/* WAKE_REG address = 0x1074 */
/* SLEEP_VALUE Data = 0x4321 */
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ATWINC acknowledges the command by sending two bytes [C9] [0].
Command
CMD_INTERNAL_READ: 0xC4
BYTE [0] = CMD_INTERNAL_READ
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = 0x00;
/* internal register read
*/
/* address = 0x01
/* clockless register
*/
*/
ATWINC acknowledges the command by sending three bytes [C4] [0] [F3].
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Then the ATWINC chip sends the value of the register 0x01 which equals 0x03.
Command
CMD_INTERNAL_WRITE: C3
BYTE [0] = CMD_INTERNAL_WRITE
BYTE [1] = address >> 8;
BYTE [1] |= (1 << 7);
BYTE [2] = address;
BYTE [3] = u32data >> 24;
BYTE [4] = u32data >> 16;
BYTE [5] = u32data >> 8;
BYTE [6] = u32data;
/* internal register write
*/
/* address = 0x01
*/
/* clockless register
/* Data = 0x01
*/
The ATWINC chip acknowledges the command by sending two bytes [C3] [0].
Scan Wi-Fi request has been sent to the ATWINC chip and the response is sent to the host successfully.
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*/
Appendix A.
A.1
How to Generate Certificates
Introduction
This chapter explains the required procedures to create and sign custom certificates using OpenSSL, to use
this guide you must install OpenSSL to your machine.
OpenSSL is an open-source implementation of the SSL and TLS protocols. The core library, written in the C
programming language, implements basic cryptographic functions and provides various utility functions.
OpenSSL can be found here: https://www.openssl.org
A.2
Steps
After installing OpenSSL, open a CMD prompt and navigate to the directory where OpenSSL was installed
(e.g.: C:\OpenSSL-Win64\bin).

First you need to generate a key for our The CA (certification authority). To generate a 4096-bit long
RSA (will create a new file CA_KEY.key to store the random key):
CMD:

Next, create your self-signed root CA certificate CA_CERT.crt; you’ll need to provide some data for your
Root certificate.
CMD:

openssl genrsa -out Custom.key 4096
Using the key generated above, you should generate a certificate request file (csr):
CMD:

openssl req -new -x509 -days 1826 -key CA_KEY.key -out CA_CERT.crt
Next step is to create the custom certificate which will be signed by the CA root certificate created earlier.
First, generate the key:
CMD:

openssl genrsa -out CA_KEY.key 4096
openssl req -new -key Custom.key -out CertReq.csr
Finally: process the request for the certificate and get it signed by the root CA.
CMD:
openssl x509 -req -days 730 -in CertReq.csr -CA CA_CERT.crt -CAkey
CA_KEY.key -set_serial 01 -out CustomCert.crt
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Appendix B.
B.1
X.509 Certificate Format and Conversion
Introduction
The most known encodings for the X.509 digital certificates are PEM and DER formats.
The PEM format is base64 encoding of the DER enclosed with between
"-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----".
B.2
Conversion Between Different Formats
The current implementation of the ATWINC root_certificate_downloader supports only DER format. So, if the
certificate is not in DER it must be converted to DER. This conversion can be done by several methods as
described in the following sub-sections.
B.2.1
Using Windows
From Windows®, double click on the .pem certificate file and then go to Details Tab and press “Copy to File”.
Follow the wizard until finish.
B.2.2
Using OpenSSL
The famous OpenSSL could be used for certificate conversion by the following command.
B.2.3
Online Conversion
There are useful online tools which provide conversion between certificate formats, which can be found
through searching online using keywords such as "OpenSSL".
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Appendix C.
C.1
How to Download the Certificate into the ATWINC
Overview
The ATWINC save the certificate inside the SPI flash in 4K sector (so the maximum size of all certificates in
flash should be less than 4K).
C.2
Certificate Downloading
To download the root certificate Execute the batch file RootCertDownload.bat inside the release package:
C.3

I2C Downloader
/src/Tools/root_certificate_downloader/debug_I2C/RootCertDownload.bat

UART Downloader
/src/Tools/root_certificate_downloader/debug UART/RootCertDownload.bat
Adding New Certificate

Open the file RootCertDownload.bat. There you find the following command:
root_certificate_downloader -n 2 NMA_Root.cer PROWL_Root.cer

Update the batch for example to add NMI_root.cer (by update the n number of certificated and add the
new certificate to the argument)
root_certificate_downloader -n 3 NMA_Root.cer PROWL_Root.cer NMI_root.cer
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Appendix D.
Firmware Image Downloader
The Firmware Downloader script use the EDBG SAMD21/W25 UART as the main interface.
D.1
1.
Downloads the serial bridge application on the SAMD21/W25 using the Atmel atprogram.exe.
2.
After downloading, the application will initialize the ATWINC in download mode and start listen on EDBG
UART for UART commands.
3.
The application will convert the UART commands to SPI commands.
4.
The script will wait a couple of seconds until the application initialization finishes, then executes the
firmware downloader, and the gain builder given the UART argument and the firmware/gain sheets path
argument.
Preparing Environment
After connecting SAM D21 Debug USB and ATWINC Virtual COM Port USB port to computer, make sure that
their drivers are already installed and correctly detected by Windows.
The ATWINC COM Port is configured (460800N-8-1) for Debug traces.
To check this, here are the steps for Windows XP and 7:
1.
142
Right click on the icon “My Computer” and a menu will appear. Scroll down and select “Manage”. The
following “Computer Management” window will appear:
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2.
From the list on the left hand side, select (click on) “Device Manager”. The “View” will change to
something very similar to the following image:
3.
In the Right Hand Panel, select (double click) Ports (COM and LPT). The “View” will change to
something like the following (actual info shown depends on your PC).
In the below image, the boards are connected and using COM15, and COM26:
Make sure the EDBG port is not in use at Atmel Studio or with any other serial monitor
before downloading. Also make sure that the firmware bin file is located at “./firmware/m2m_aio.bin” and gain files are located at “./Tools/gain_builder/gain_sheets/”.
The same thing is valid for SAMW25, by running “download_all_sb_samw25_xplained_pro.bat”.
D.2
Download Firmware
Run the "download_all_sb_samd21_xplained_pro.bat" script that is associated with the release to download
firmware and gain settings for SAM D21.
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Appendix E.
E.1
Gain Settings Builder
Introduction
Gain setting values, are those values used by RF with different rates to configure transmission power.
This appendix helps to calculate these values and store them in Flash to use them otherwise default values will
be used.
E.2
Preparing Environment
Make sure the environment is ready for building and downloading gain settings as in Appendix D: Firmware
Image Downloader.
E.3
How to use
E.3.1
Method 1
E.3.2

Replace the data of samd21_gain_setting.csv file in the project’s folder with the new data where the file’s
location is the default (./Tools/gain_builder/gain_sheets/)

Then run your application. It will calculate and store you data in Flash.
Method 2

If you have a different file with data in a different path, then open “gain_build_and_download.bat” patch
file and update it with the new path and file like:
-fw_path ../gain_sheets/samd21_gain_setting.csv → -fw_path c:/gain_values.csv

Then run your application by double click on modified patch file
Registers’ values for each channel
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ch
–
The .csv file must be sorted based on gain rates like the templates
–
There are two different buses to run your app I2C or UART
–
Your file must have 15 columns and 21 Rows for all channels such as the following
template:
1
2
3
4
5
6
7
8
9
10
11
1
2
5.5
11
6
9
12
18
Insert your values here
24
36
48
54
mcs0
mcs1
mcs2
mcs3
mcs4
mcs5
mcs6
mcs7
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13
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Appendix F.
Revision History
Doc Rev.
Date
42566A
04/2016
Comments
Initial document release.
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© 2016 Atmel Corporation. / Rev.: Atmel-42566A-ATWINC3400-WiFi-BLE-Network-Controller-Software-Design-Guide_UserGuide_042016.
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