W5500 can help a microcontroller communicate over wired Ethernet. However, a 100 Mbps link does not guarantee 100 Mbps application throughput, and plugging in a cable does not complete a cloud connection. This guide covers interfaces, connection resources, supporting circuitry and sample tests.
See the W5500 product and inquiry page. Use manufacturer documentation for engineering specifications.
1. What problem does W5500 solve?
If an existing device measures temperature, controls a motor or reads instruments and needs to send data over a cable, W5500 is a candidate when the MCU has a suitable SPI interface.
WIZnet's W5500 integrates hardwired TCP/IP processing and a 10/100 Ethernet MAC and PHY. It communicates with a host over SPI and provides eight independent hardware sockets and 32 KB of combined internal transmit/receive buffers. See WIZnet's official documentation.
The host MCU handles acquisition, control logic and application messages.
W5500 handles its supported network protocols and Ethernet communication.
Supporting circuitry provides power, clocking and the cable connection.
It is not a general-purpose replacement for the MCU or a complete standalone application module.
2. Why can throughput be much lower than link speed?
10/100 Ethernet describes link capability, not delivered application throughput. Data passes from the MCU over SPI and then through the network. SPI configuration, software, message size, buffer management and the receiving system affect results.
For sixteen channels reporting 1,000 two-byte values per second each:
Raw data rate = 16 × 1,000 × 2 = 32,000 bytes per second.
Add timestamps, message headers and retransmission overhead. This is a requirements example, not a measured chip benchmark. Occasional status uploads do not necessarily require a full-rate link. Continuous images or high-volume acquisition require testing on the real hardware and software.
Specify acceptance in terms of message size, sending rate, network conditions, test duration, throughput, latency and recovery behavior.
3. Do eight sockets mean eight connected devices?
Device count alone is insufficient. A socket is a communication resource. One peer may require several connections; a UDP application may exchange messages with several peers through one socket. Other network tasks may also consume resources.
Server uploads: which protocol is used, and is the connection persistent?
Host control: must multiple clients connect simultaneously?
Network configuration: is DHCP and its supporting software required?
Name resolution: are DNS and temporary communication resources required?
Maintenance: are extra diagnostic connections needed?
Each socket does not have its own 32 KB buffer.The 32 KB figure is the combined internal transmit/receive total. Allocate buffers according to the application and the W5500 datasheet.
4. Why is TCP support not a complete cloud solution?
A cloud platform may require message formats, authentication, certificates, encryption and reconnection logic. TCP/IP capability does not automatically provide these functions.
Confirm whether the platform uses MQTT, HTTP or another application protocol, whether TLS is required, where encryption and certificates are handled, whether the host has enough program and working memory, and how disconnections are recovered. Additional requirements such as IPv6 also need explicit validation. Evaluate the complete software solution rather than approving the chip name alone.
5. Choose a chip, module or development board
Bare IC:for a custom PCB; check the ordering code, package, packing and supporting circuit.
Ethernet module:reduces some hardware work; check the module code, schematic, supply and interfaces.
Development board:for driver and network evaluation; check board revision, example software and pin definitions.
The chip does not include the entire network connector circuit. Follow manufacturer references for power, clocking, magnetics and connectors. WIZnet offers modules combining W5500 and an RJ45 connector with integrated magnetics, illustrating the different delivery scope: official module example.
A module accepting a 5 V supply does not establish that every signal pin accepts 5 V. Verify supply inputs and logic levels separately.
6. Test more than a successful connection
Sending one message establishes communication only under that condition. Before production, test:
Normal traffic:use realistic message lengths, rates and connection counts; check integrity and latency.
Cable reconnection:does communication recover without a manual reset?
Server restart:can connections be rebuilt, and how is unsent data handled?
Continuous operation:observe buffers, connections and error handling over time.
Multiple devices:check address and identity provisioning to avoid duplicate configuration conflicts.
Record the MCU, board and firmware revisions, SPI settings and network environment so samples and batches can be compared.
7. Purchasing checklist
Deliverable: W5500 bare IC or an explicitly identified module.
Manufacturer, complete ordering code, sample quantity and first production quantity.
Packing, target arrival date, lot and traceability requirements.
For modules: pin definitions, supply conditions, schematic and board revision.
Substitution rule: part or board-revision changes require prior approval.
Compare the same deliverable. Bare chips, modules and development boards are not directly comparable quotations. See our guide to comparing chip supplier quotations.
Send the deliverable type, complete code, quantity and target date through the W5500 product page. Pricing, quantity and lead time are subject to the actual quotation.