Wiznet makers

How to HTTP Client Example (MicroPython)

This program demonstrates how to implement a simple HTTP Client using the W55RP20 S2E board via UART or SPI interface. The Raspberry Pi Pico (Host) configures the W55RP20 S2E as a TCP Client (OP4) using AT commands. Once connected to a web server (e.g., httpbin.org), it enters Data Mode to send an HTTP GET request and print the received HTML/JSON response to the console.

Step 1: Prepare software

The following software is required to run and test the MicroPython example.

• Thonny : An integrated development environment for MicroPython. used to write, upload, and run code.
• Public Test Server: We will use httpbin.org (a simple HTTP Request & Response Service) for testing, so no local server software is strictly required.

Step 2: Prepare hardware

1. Connect GPIO13 according to the selected UART/SPI mode of the W55RP20 EVB Pico, as illustrated below.

2. Connect the Raspberry Pi Pico and the W55RP20 EVB Pico using jumper wires as shown below, depending on the selected UART/SPI mode.

• Important Note on Mode Switching: In this example setup, GPIO 13 of the W55RP20 EVB Pico is physically connected to GPIO 13 of the Raspberry Pi Pico. The Host Pico sets the mode (High/Low) automatically based on the software configuration.
• If you change the MODE in the code (e.g., UART ↔ SPI): You MUST reset both boards (Raspberry Pi Pico and W55RP20 EVB Pico) to ensure the mode is switched and recognized correctly.

If UART mode :

If SPI mode :

3. Connect the Raspberry Pi Pico to your PC (desktop or laptop) using a 5-pin Micro USB cable.

4. Connect the W55RP20 EVB Pico to your PC (desktop or laptop) using a USB Type-C cable.

Step 3: Setup Example

• Raspberry Pi Pico (Master) : Getting started with Raspberry Pi Pico (MicroPython)

Please refer to the link below to install the MicroPython firmware on the Raspberry Pi Pico.

• W55RP20 EVB Pico : Getting started with W55RP20 EVB Pico

Please refer to the link below for instructions on how to use the W55RP20 S2E.

Step 4: Upload Code

• Raspberry Pi Pico

Open Thonny IDE and connect to the Raspberry Pi Pico. Upload the following driver and example files to the Pico's storage.

Required Files:

1. w55rp20_s2e_uart.py (Required for UART mode)
2. w55rp20_s2e_spi.py (Required for SPI mode)

Example Application Files (Choose one to test):

• 07_http_client.py

Configuration: Before running an example, open the Python file you intend to use and modify the User Configuration section at the top.

# 05_http_client.py
#
# HTTP client example (Supports both SPI and UART modes):
# - Configure the module as TCP client + DHCP
# - Connect to httpbin.org and send HTTP GET requests
# Select mode by changing the MODE variable below.

import time

# -------------------------------------------------------------------------
# Configuration
# -------------------------------------------------------------------------
MODE = "uart"   # Set to "spi" or "uart"

# IP Configuration Mode
USE_DHCP = True  # True: DHCP (IM=1), False: Static IP (IM=0)

# Network Configuration
LOCAL_IP    = "192.168.11.100"  # Local IP (Used when USE_DHCP=False)
SUBNET_MASK = "255.255.255.0"   # Subnet Mask (Used when USE_DHCP=False)
GATEWAY     = "192.168.11.1"    # Gateway (Used when USE_DHCP=False)
DNS_SERVER  = "8.8.8.8"         # DNS Server (Used when USE_DHCP=False)
REMOTE_IP   = "httpbin.org"  # HTTP server (domain or IP)
REMOTE_PORT = "80"           # HTTP port
.
.

• W55RP20 EVB Pico

Following Step 3 in the Getting Started Guide, program the W55RP20 EVB Pico with the UF2 file and write the MAC address to complete the setup.

Step 5: Run

Check IP

Open a command prompt on your PC and type ping httpbin.org. Copy the IP address and paste it into the REMOTE_IP variable in 07_http_client.py.

Pico (Thonny):

• Open 07_http_client.py.
• Run the script (Press F5).

Monitor:

• Watch the Thonny shell.
• You should see the initialization logs.
• After the reboot, the script will send the data.

Success: You will see the HTTP headers and a JSON body printed in the console, similar to:

--- HTTP Response Start ---
HTTP/1.1 200 OK
Date: Mon, 01 Jan 2024 12:00:00 GMT
Content-Type: application/json
Content-Length: 300
Connection: close
Server: gunicorn/19.9.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true

{
  "args": {}, 
  "headers": {
    "Host": "httpbin.org", 
    "User-Agent": "W55RP20-S2E", 
    ...
  }, 
  "origin": "xxx.xxx.xxx.xxx", 
  "url": "http://httpbin.org/get"
}
--- HTTP Response End ---