STM32CubeMX series | Use BearPi hardware SPI to drive W5500 Ethernet module

This article records in detail how to use STM32CubeMX to configure the hardware SPI peripherals of STM32L431RCT6 to communicate with W5500 to drive the Ethernet module.
details

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1. Preparation

Hardware preparation

  • Development board

First, you need to prepare a development board, here I am preparing the STM32L4 development board (BearPi):

  • W5500 Ethernet module

Here I use the common Ethernet module W5500:

Software preparation

  • Need to install Keil-MDK and the corresponding package of the chip in order to compile and download the generated code;
  • Prepare a serial port debugging assistant, here I am using Serial Port Utility;
  • Prepare a network debugging assistant, here I am using sockettool;

2. Generate MDK project

Select chip model

Open STM32CubeMX, open the MCU selector:

Search and select the chip STM32L431RCT6:

Configure the clock source
  • If you choose to use an external high-speed clock (HSE), you need to configure RCC in System Core;
  • If the default internal clock (HSI) is used, this step can be skipped;

Here I use an external clock:

Configure Ethernet module to control GPIO

There are two GPIOs that need additional configuration for the Ethernet module:

Ethernet module pin nameGPIOeffect
RSTPC9Ethernet module hard reset
INTPA0Interrupt pin

The reset pin can be configured as output mode:

The interrupt pin needs to receive the interrupt from the Ethernet module, so the EXTI external interrupt pin needs to be configured:

Configure SPI1 interface

In this experiment, I connected the Ethernet module to the SPI1 interface, and the pin correspondence table is as follows:

It should be noted that the SPI chip select pins are not controlled by hardware SPI peripherals, but are configured as ordinary GPIOs and controlled manually .

Ethernet module pinsMCU pin
MISOPA6(SPI1_MISO)
MOSIPA12(SPI1_MOSI)
SCSPA4(SPI1_NSS)
SCLKPA1(SPI1_SCK)

There are three points to note when configuring the SPI interface:

① Frequency division coefficient;
② CPOL: When the CLK is idle, the level is high or low;
③ CPHA: Sampling on the first clock edge or sampling on the second clock edge;

Next, start to configure the SPI1 peripheral. First, configure the mode and pins of the SPI1 peripheral:

Because you chose not to use the hardware SPI peripheral to control the chip select pin, you need to manually configure the chip select pin PA4:

The SPI bus clock given in the W5500 manual is 80Mhz:

SymbolDescriptionMinMaxUnits
FsckSCLK Clock Frequency80MHz
TWHSCLK High duration6ns
TWLSCLK Low duration6ns
TCSnSCS High duration5ns

However, it should be noted that the manual clearly indicates that the actual guarantee is at least 33.3Mhz, so for the sake of safety, the SPI bus clock is configured as 20Mhz in this experiment :

5 Theoretical Guaranteed Speed

For CPOL, W5500 supports both modes. Select the LOW mode when idle. The first clock edge is given in the CPHA manual:

The first clock edge is given in the CPHA manual

In summary, the timing parameters are configured as follows:

Configure the serial port

The development board has a CH340z for serial port, which is connected to USART1.

Next, start the configuration USART1:

Configure the clock tree

The highest frequency of STM32L4 is 80M, so configure PLL, and finally use HCLK = 80Mhz:

Generate project settings

Code generation settings

Finally set to generate a separate initialization file:

Generate code

Click GENERATE CODEto generate MDK-V5 project:

3. Redirect printf function to USART1

Reference: [STM32Cube_09] Multiple methods to redirect printf function to serial port output .

4. Porting W5500 official driver library

4.1. Download the official driver library

W5500 officially provides ioLibrary v2.0.0. ioLibrary is the Ethernet driver library of the WIZnet chip, which includes drivers and application protocols. This driver (ioLibrary) can be used for the application design of WIZnet TCP/IP chips, such as W5500, W5300, W5200, W5100, W5100S.

There are two download addresses:

The source code directory structure is shown in the figure:

  • Ethernet: SOCKET API interface similar to BSD, and WIZCHIP (W5500 / W5300 / W5200 / W5100 / W5100S) driver
  • Internet: Various application layer protocol stacks
    • DHCP client
    • DNS client
    • FTP client
    • FTP server
    • SNMP agent/trap
    • SNTP client
    • TFTP client
    • HTTP server
    • MQTT Client

4.2. Add the driver library to the project

Create a new Hardware/W5500 under the project directory and copy all three folders in the driver library:

Note that only the files under Ethernet are required, and the files in the other two folders can be added optionally, which will be used in the test later.

Next, add files related to W5500 in the Ethernet directory to the MDK project:

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