Azure IoT Hub WiFi Gateway, LED ON/OFF

I The process of connecting W5100S-EVB-Pico to Azure IoT Hub by MQTT using Micropython and sending and receiving messages.

I used a SAS Token authentication method for IoT Hub.

Components

1. H/W

• W5100S-EVB-Pico for Ethernet an MCU
• WizFi360 for Wi-Fi
• Micro 5pin USB cable
• LAN cable

Details on W5500 and WizFi360 PIN Connection

TDX and RDX jumpers from the WizFi to send UART data to the UART W5500-EVB-Pico pins.

1. 1 WizFi360 Pin Map

1. 2 W5500-EVB-Pico Pin Map

https://docs.wiznet.io/Product/iEthernet/W5500/w5500-evb-pico

2. S/W

2.1 Prepare Azure Resource

Create a Azure IoT Hub

There are various ways to create an Azure IoT Hub, such as the Azure portal, Azure CLI, REST API, etc. In the beginning, we mainly use the method of creating through the Azure portal.

Instructions can be found at the link below.

• Create an IoT hub using the Azure portal
• Azure IoT Explorer

How to Generate and Register Cert.

Follow this guide: https://www.hackster.io/lawrence-wiznet-io/azure-iot-cloud-monitored-and-controlled-raspberry-pi-pico-65fc93

2.2 RP2040 C/C++ Development Environment

https://maker.wiznet.io/eric_g/projects/development-environment-w5100s-evb-pico-c-c-in-windows/?page=4&sercateidx=0&serob=1

C/C++ Firmware

Build

The build operation used Raspberry Pi C/C++ environment.

https://maker.wiznet.io/eric_g/projects/development-environment-w5100s-evb-pico-c-c-in-windows/?page=4&sercateidx=0&serob=1

2-1. Download and Install Programs for the integrated Development Environment

Release v0.3.4 · ndabas/pico-setup-windows · GitHub

2.2 Repository clone

Raspberry Pi Pico W5x00 Azure IoT SDK Examples

RP2040 - W5100S or W5500 network examples - Azure IoT Cloud functions, Azure IoT SDK, Azure IoT device client, and server.

• 'iothub_ll_telemetry_sample' application result
• iothub_ll_c2d_sample' application result
• iothub_ll_client_x509_sample' application result
• prov_dev_client_ll_sample' application result

Build W5100S-EVB-Pico Device Firmware

Device Source code

I uploaded the RP2040 (W5500/W5100 and WizFi360) Gateway device code to the link below to control through the WiFi IoT device's MAC address.

• https://github.com/Wiznet/RP2040-WizFi360-Gateway-C

The Azure IoT Hub Gateway contents have been added and modified from the RP2040-HAT-AZURE-C: original example code.

• W5100S/W5500 Azure IoT Hub Connection Settings
• Modification of telemetry message transmission to / receiving from IoT Devices through MAC address

Clone the Repository including the submodules and retrieve the submodules.

git clone https://github.com/Wiznet/RP2040-HAT-AZURE-C.git
cd RP2040-HAT-AZURE-C

git submodule update --init

• How to Manage the Device Information for this Gateway

This gateway executes the ethernet thread and Wi-Fi server thread. When a client has physically connected to AP, we called a connected state. It adopted in Wi-Fi driver; I modified CMSIS WiFi driver WiFi_WizFi360.h and WiFi_WizFi360.c to manage connection information.

typedef struct {
  uint8_t conn_mac[8];
  uint8_t conn_ip[4];
} CONNECTED_MAC_IP_s;

When a client is logically connected to AP's server, we called link connected. So gateway manages two separate clients' IP and MAC address data. The gateway sends and receives each IoT device's data between the Azure IoT hub and IoT devices by distinguishing the IoT device's MAC address. We called it a linked MAC address.

/* ------------------------------------------------------------------------
 * WizFi360 added for IoT Devices
 * Station Connection Event Declaration
 * : to update/delete Mac Address for distinguishing IoT Devices
 * -----------------------------------------------------------------------*/
void update_connected_macIp(uint8_t macAddr[6], uint8_t ipAddr[4]);
void update_linked_mac(void);
int update_unliked_mac(uint8_t macAddr[6]);
CONNECTED_MAC_IP_s ConnSta[4];   // Station's mac address connected to AP
uint8_t LinkedMac[5][6] = {0, }; // Client's mac address connected to Server

• Set your board network information and select a sample application

In the following RP2040-HAT-AZURE-C/examples/main.c source file, find the line similar to this and replace it as you want:

(...)

// The application you wish to use should be uncommented
//
#define APP_TELEMETRY
//#define APP_C2D
//#define APP_CLI_X509
//#define APP_PROV_X509

// The application you wish to use DHCP mode should be uncommented
#define _DHCP
static wiz_NetInfo g_net_info =
    {
        .mac = {0x00, 0x08, 0xDC, 0x12, 0x34, 0x56}, // MAC address
        .ip = {192, 168, 11, 2},                     // IP address
        .sn = {255, 255, 255, 0},                    // Subnet Mask
        .gw = {192, 168, 11, 1},                     // Gateway
        .dns = {8, 8, 8, 8},                         // DNS server
#ifdef _DHCP
        .dhcp = NETINFO_DHCP // DHCP enable/disable
#else
        // this example uses static IP
        .dhcp = NETINFO_STATIC
#endif
};

• Set the key information

Copy & Paste the proper connection string and key value from the Azure Portal to RP2040-HAT-AZURE-C/examples/sample_certs.c:

/* Paste in your IoT hub connection string  */
const char pico_az_connectionString[] = "[device connection string]";

const char pico_az_x509connectionString[] = "[device connection string]";

const char pico_az_x509certificate[] =
"-----BEGIN CERTIFICATE-----""\n"
"-----END CERTIFICATE-----";

const char pico_az_x509privatekey[] =
"-----BEGIN PRIVATE KEY-----""\n"
"-----END PRIVATE KEY-----";

const char pico_az_id_scope[] = "[ID Scope]";

const char pico_az_COMMON_NAME[] = "[custom-hsm-device]";

const char pico_az_CERTIFICATE[] =
"-----BEGIN CERTIFICATE-----""\n"
"-----END CERTIFICATE-----";

const char pico_az_PRIVATE_KEY[] =
"-----BEGIN PRIVATE KEY-----""\n"
"-----END PRIVATE KEY-----";

2.3 Build and Run

1. Build and Run the application

Run VS Code or Developer command prompt for VS 2019 and build the application. copy main.uf2 file into Raspberry Pi Pico board.

Firmware Upload

Upload the firmware to the device.

Enter Boot Mode

If you press the RUN button while holding down the BOOTSEL button, it enters the boot mode and there is no need to re-apply the power.

3. Setup Azure IoT hub

Install Tools and libraries

There are several ways to get information, and among them, I used IoT Explorer.

• Azure IoT Hub Release
• Releases · Azure/azure-iot-explorer (github.com)

Install the PC library in the Azure environment.

Get device information from IoT Explorer

Set up IoT Explorer IoT Hub connection

Device creation

detailed information: https://maker.wiznet.io/eric_g/projects/azure-iot-gateway-with-w500-and-wizfi360/

4. Execution and monitoring

Simple Telemetry Test: Recieve the Messages from the IoT Device with the Device's own MAC address

Cloud-to-Device message: Send the Messages to the IoT Device with the Device's own MAC address

IoT Device's Received Message Log

Sending message 1 to IoTHub
Message:
iotSocketRecv data is 123

Sending message 7 to IoTHub
Message:
-> 08:18:48 PUBLISH | IS_DUP: false | RETAIN: 0 | QOS: DELIVER_AT_LEAST_ONCE | TOPIC_NAME: devices/wiznetGateway/messages/events/display_message=Hello_RP2040_W5100S&%24.cid=CORE_ID&%24.mid=MSG_ID&%24.ct=application%252fjson&%24.ce=utf-8 | PACKET_ID: 9 | PAYLOAD_LEN: 53

<- 08:18:50 PUBACK | PACKET_ID: 9
Confirmation callback received for message 7 with result IOTHUB_CLIENT_CONFIRMATION_OK

iotSocketRecv data is wiznet device1

<- 07:42:36 PUBLISH | IS_DUP: false | RETAIN: 0 | QOS: DELIVER_AT_LEAST_ONCE | TOPIC_NAME: devices/wiznetGateway/messages/devicebound/%24.mid=080d3e1f-e25e-437e-b15b-5525878f9439&%24.to=%2Fdevices%2FwiznetGateway%2Fmessages%2Fdevicebound&mac=48%3A60%3A5F%3A2F%3A76%3AC8 | PACKET_ID: 5 | PAYLOAD_LEN: 9
Received Binary message
Message ID: 080d3e1f-e25e-437e-b15b-5525878f9439
 Correlation ID: <unavailable>
 Data: <<<Power Off>>> & Size=9

Message Properties:
        Key: mac Value: 48:60:5F:2F:76:C8
macstr: 48:60:5F:2F:76:C85h en = 26
Received C-to-D Message: Power Off
MQTT Subsribed the msg to client: Power Off, idx = 1

Message Call Count is 4:

-> 07:42:37 PUBACK | PACKET_ID: 5
iotSocketSend data is Power Off

How to consist the Remote IoT Device

You can set it up so that Azure IoT Hub can control IoT Devices (Client) through this Gateway refer to the below.

TCP Client LED ON / OFF Reference and Example:

https://maker.wiznet.io/eric_g/projects/tcp-client-led-on-off-for-raspberry-pi-pico-with-wizfi360-1/