STM32配合W5500网卡连接华为云物联网平台通信-环球新要闻

【1】W5500网卡

W5500是一种基于TCP/IP协议的网络通讯芯片，可以提供网络连接功能，相当于是一种嵌入式以太网控制器，具有低功耗、高速传输、易于集成等特点。W5500芯片能够支持TCP、UDP、IPv4、ARP、ICMP、IGMP等协议，使得它变得非常适合用于嵌入式设备与互联网之间的通信需求，例如智能家居、工业控制、远程监控等场景。W5500网卡还有一个特点是它支持硬件协议堆栈，这意味着它可以非常快地执行协议栈中的操作，从而大大提高了数据传输的效率。同时，W5500还具有较低的功耗，因此非常适合嵌入式设备这种资源受限的场景。

W5500芯片通过SPI总线与MCU进行通信，MCU需要实现SPI总线协议来控制W5500进行数据交互。

【2】SPI协议

SPI（Serial Peripheral Interface）协议是一种串行外设接口协议，是一种全双工、同步的接口技术，通常用于连接微控制器和外设，例如传感器、存储器、显示器等。SPI协议传输效率高，使用简单，开销较小，因此被广泛应用于嵌入式系统中。

SPI协议使用主从模式，主设备可以控制多个从设备，从设备不能主动向主设备发送数据或信息。SPI协议具有以下几个重要的信号线：

时钟

SPI协议的数据传输是基于数据字节的传输，主设备每次通过MOSI线发送一个字节，从设备通过MISO线接受该字节，并回传一个字节。数据的传输顺序可以根据时钟线（SCLK）的极性和相位配置为四种不同的模式。SPI协议支持的模式受闪存、RAM、I/O和模拟/数字转换器等外设和类型的限制。

【3】W5500建立TCP协议通信

以下是STM32通过W5500建立TCP通信，并访问TCP服务器，完成数据收发的示例代码。

代码中使用了STM32 HAL库，W5500的IP地址和端口号需要根据实际情况进行设置。

#include "main.h"#include "stdio.h"#include "stm32f1xx_hal.h"#include "wizchip_conf.h"#include "socket.h"#include "dhcp.h"/* Privatevariables */SPI_HandleTypeDef hspi1;/* Private function prototypes */void SystemClock_Config(void);static void MX_GPIO_Init(void);static void MX_SPI1_Init(void);void W5500_Init(void);uint8_t socket;uint8_t buf[1024];int main(void){ /* MCU Configuration */ HAL_Init(); SystemClock_Config(); MX_GPIO_Init(); MX_SPI1_Init(); /* W5500 Initialization */ W5500_Init(); /* Connect to TCP Server */ uint8_t server_ip[4] = {192, 168, 1, 100}; uint16_t server_port = 5000; uint8_t connected = 0; while (!connected) { if (getSn_SR(socket) == SOCK_CLOSED) { socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (socket == 0xFF) { /* Error: Failed to create socket */ } else { /* Configure socket */ uint8_t dest_ip[4] = {192, 168, 1, 200}; uint16_t dest_port = 5000; uint8_t buf[4]; IINCHIP_WRITE(Sn_DIPR(socket), dest_ip); IINCHIP_WRITE(Sn_DPORT(socket), dest_port); IINCHIP_SOCKET_CONTROL(socket, Sn_CR_OPEN); HAL_Delay(10); /* Try to connect to server */ IINCHIP_SOCKET_CONTROL(socket, Sn_CR_CONNECT); HAL_Delay(1000); if (getSn_SR(socket) == SOCK_ESTABLISHED) { connected = 1; } else { /* Connection failed */ IINCHIP_SOCKET_CONTROL(socket, Sn_CR_CLOSE); HAL_Delay(10); } } } } /* Send Data to Server */ uint8_t tx_data[4] = {0x01, 0x02, 0x03, 0x04}; write(socket, tx_data, sizeof(tx_data)); /* Receive Data from Server */ int rx_len = 0; while (1) { rx_len = getSn_RX_RSR(socket); if (rx_len > 0) { read(socket, buf, rx_len); /* Data received from server, do something */ }= SPI_DIRECTION_2LINES;hspi1.Init.DataSize = SPI_DATASIZE_8BIT;hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;hspi1.Init.NSS = SPI_NSS_SOFT;hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_128;hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;hspi1.Init.TIMode = SPI_TIMODE_DISABLE;hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;hspi1.Init.CRCPolynomial = 10;HAL_SPI_Init(&hspi1);}/* GPIO Initialization */static void MX_GPIO_Init(void) {GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOA_CLK_ENABLE();/*Configure GPIO pin : PA4 */GPIO_InitStruct.Pin = GPIO_PIN_4;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);}/* System Clock Configuration */void SystemClock_Config(void) {RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Initializes the RCC Oscillators according to the specified parametersin the RCC_OscInitTypeDef structure. */RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks */RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { Error_Handler();}}

【4】封装MQTT协议报文

下面使用MQTT client library for Contiki来连接MQTT服务器。这个库适用于不同的平台，包括STM32。在使用前，需要根据需求进行一些配置，例如：指定MQTT服务器的地址和端口号，配置MQTT客户端ID和主题等。

#include "contiki.h"#include "contiki-net.h"#include "mqtt.h"#include "stm32f1xx_hal.h"#include "wizchip_conf.h"#include "w5500.h"/* MQTT Configuration */#define SERVER_IP_ADDR "192.168.1.100"#define SERVER_PORT 1883#define MQTT_CLIENT_ID "mqtt_stm32"#define MQTT_TOPIC "example_topic"/* Network Configuration */static wiz_NetInfo gWIZNETINFO = { .mac = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06}, .ip = {192, 168, 1, 200}, .sn = {255, 255, 255, 0}, .gw = {192, 168, 1, 1}, .dns = {8, 8, 8, 8}, .dhcp = NETINFO_STATIC };/* W5500 Buffer */static uint8_t buf[2048];/* Prototypes */static void MX_SPI1_Init(void);static void MX_GPIO_Init(void);void SystemClock_Config(void);void Error_Handler(void);void W5500_Select(void);void W5500_UnSelect(void);uint8_t W5500_WriteByte(uint8_t b);uint8_t W5500_ReadByte(void);void MQTT_Callback(struct mqtt_connection *m, void *userdata, mqtt_event_t event, mqtt_data_t *data);/* MQTT Connection */static struct mqtt_connection mqtt_conn;static struct mqtt_message *msg_ptr = NULL;static uint8_t mqtt_connected = 0;PROCESS(mqtt_process, "MQTT Process");AUTOSTART_PROCESSES(&mqtt_process);/* MQTT Process */PROCESS_THREAD(mqtt_process, ev, data){ PROCESS_BEGIN(); /* Initialize W5500 */ reg_wizchip_cs_cbfunc(W5500_Select, W5500_UnSelect); reg_wizchip_spi_cbfunc(W5500_ReadByte, W5500_WriteByte); wizchip_init(buf, buf); /* Configure Network */ ctlnetwork(CN_SET_NETINFO, (void*)&(gWIZNETINFO)); /* DHCP Initialization */ uint8_t /* Enable DHCP */ dhcp_client_start();/* Wait for DHCP to finish */while (gWIZNETINFO.dhcp == NETINFO_DHCP) { HAL_Delay(1000); // wait for DHCP to finish } /* Print IP Address */ printf("IP address: %d.%d.%d.%dn", gWIZNETINFO.ip[0], gWIZNETINFO.ip[1], gWIZNETINFO.ip[2], gWIZNETINFO.ip[3]); /* Configure MQTT Connection */ memset(&mqtt_conn, 0, sizeof(mqtt_conn)); mqtt_conn.state = MQTT_INIT; mqtt_conn.host = SERVER_IP_ADDR; mqtt_conn.port = SERVER_PORT; mqtt_conn.client_id = MQTT_CLIENT_ID; mqtt_conn.user_data = NULL; mqtt_conn.user_name = NULL; mqtt_conn.password = NULL; mqtt_conn.protocol_version = MQTT_VERSION_3_1_1; mqtt_conn.keep_alive = 60; /* Connect to MQTT Server */ mqtt_connect(&mqtt_conn); /* Wait for MQTT Connection to Finish */ while (!mqtt_connected) { PROCESS_PAUSE(); } /* Publish Message to MQTT Server */ static char msg[100] = "Hello from STM32 using MQTT protocol!"; msg_ptr = mqtt_msg_publish_init(msg, strlen(msg), MQTT_TOPIC, MQTT_QOS_LEVEL_0, MQTT_RETAIN_OFF); mqtt_publish(&mqtt_conn, msg_ptr); /* Wait for Message to be Sent */ while (mqtt_conn.out_buffer_sent == 0) { PROCESS_PAUSE(); } /* Subscribe to MQTT Topic */ mqtt_subscribe(&mqtt_conn, MQTT_TOPIC, MQTT_QOS_LEVEL_0); /* Loop Forever */ while (1) { PROCESS_PAUSE(); } PROCESS_END();} /* SPI Initialization / static void MX_SPI1_Init(void) { / SPI1 parameter configuration*/hspi1.Instance = SPI1;hspi1.Init.Mode = SPI_MODE_MASTER;hspi1.Init.Direction = SPI_DIRECTION_2LINES;hspi1.Init.DataSize = SPI_DATASIZE_8BIT;hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;hspi1.Init.NSS = SPI_NSS_SOFT;hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_128;hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;hspi1.Init.TIMode = SPI_TIMODE_DISABLE;hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;hspi1.Init.CRCPolynomial = 10;HAL_SPI_Init(&hspi1);}/* GPIO Initialization */static void MX_GPIO_Init(void) {GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOA_CLK_ENABLE();/*Configure GPIO pin : PA4 */GPIO_InitStruct.Pin = GPIO_PIN_4;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);}/* System Clock Configuration */void SystemClock_Config(void) {RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Initializes the RCC Oscillators according to the specified parametersin the RCC_OscInitTypeDef structure. */RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks */RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { Error_Handler();} }/* Error Handler */void Error_Handler(void) {while (1) { // error } } /* W5500 Select */ void W5500_Select(void) { HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET); } /* W5500 Unselect */ void W5500_UnSelect(void) { HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET); } /* W5500 Write Byte */ uint8_t W5500_Writebyte(uint8_t b) { uint8_t res; HAL_SPI_TransmitReceive(&hspi1, &b, &res, 1, HAL_MAX_DELAY); return res; } /* W5500 Readbyte */ uint8_t W5500_Readbyte(void) { uint8_t b = 0xff; HAL_SPI_TransmitReceive(&hspi1, &b, &b, 1, HAL_MAX_DELAY); return b;}/* MQTT Callback */void MQTT_Callback(struct mqtt_connection *m, void *userdata, mqtt_event_t event, mqtt_data_t *data) { switch (event) { case MQTT_EVENT_CONNECTED: printf("MQTT connectedn"); mqtt_connected = 1; break; case MQTT_EVENT_DISCONNECTED: printf("MQTT disconnectedn"); mqtt_connected = 0; break; case MQTT_EVENT_PUBLISHED: printf("MQTT message publishedn"); break; case MQTT_EVENT_SUBACK: printf("MQTT subscribed to topicn"); break; case MQTT_EVENT_UNSUBACK: printf("MQTT unsubscribed from topicn"); break; case MQTT_EVENT_DATA: printf("MQTT received messagen"); printf("Topic: %.*sn", data->topic_name_size, data->topic_name); printf("Message: %.*sn", data->data_size, (char *)data->data); break; default: break; }}