STM32 - WIZnet W5500

The WIZnet W5500 Ethernet chip provides an easy Ethernet network solution for many microprocessors/microcontrollers. Using a SPI interface and sample library code, most any processor can use this device to get connected to a network.

Hardware Interface

In my case, I purchased a small development module from Amazon.com.
This same module is readily available on Ebay.com and Aliexpress.com
Examples:
  https://www.amazon.com/AITRIP-Ethernet-Hardware-Microcontroller-Interface/dp/B09FG5VZFS/ref=sr_1_10   
  https://www.aliexpress.us/item/3256801465688850.html

A 10 conductor, 2x5 pin header, provides the electrical connection between the host and this module
I wired mine using a female-female ribbon cable as follows:
Wire Color   Signal	 W5500 Module Pin  NUCLEO-F103RB Pin	Comment
Brown        Not Connected  J1-1             NC		
Red          SPI-SCLK       J1-2             SCLK	SPI2_SCK, PB13, CN10-30	
Orange       INTn           J1-3             INT	PB11, CN10-18	Active low
Yellow       SPI-CSn        J1-4             SCS	SPI2_NCS, PB12, CN10-16	Active Low Chip Select
Green        RSTn           J1-5             nRST	PB10, CN10-25	Active Low, 500us min
Blue         MOSI           J1-6             MOSI	SPI2_MOSI, PB15, CN10-26	
Violet       GND            J1-7             GND	GND, CN10-20	
Grey         MISO           J1-8             MISO	SPI2_MISO, PB14, CN10-28	
White        5.0V (NC)      J1-9             NC		
Black        3.3V           J1-10            3.3V	+3V3, CN7-16

Information in the comment field describes what pin/function I connected to on my NUCLEO-F103RB board.

Target Software Interface

The WIZnet software library, "ioLibrary_Driver-master", https://github.com/Wiznet/ioLibrary_Driver
interfaces to the target via function pointers.
Need to implement the following functions (function name not important):
void W5500_Select(void);   // Drive the SPI-CSn signal low, selecting the device
void W5500_Deselect(void); // Drive the SPI-CSn signal high, deselecting the device
void W5500_WriteByte(void); // Write a single byte to the device
uint8_t W5500_ReadByte(void); // Read a single byte from the device
void W5500_WriteBuff(uint8_t* buff, uint16_t len); // Write one or more bytes from a buffer
void W5500_ReadBuff(uint8_t* buff, uint16_t len);  // Read one or more bytes into a buffer

For DHCP, a couple call-back functions need implementations:
void Callback_IP_Assigned(void);
void Callback_IP_Conflict(void);