PN学堂GD32教程第21篇——Wifi物联网技术

21.1 WIFI模组和AT指令介绍开发板上的ESP8264具有串口透传转换为MQTT协议的功能注意RXD0和TXD0是烧录ESP8264固件的调试口与单片机连接的应该用IO6(RXD)、IO7TXD:21.2 基于非阻塞方法实现AT指令的驱动乐鑫官方说明AT 命令集 - ESP32-C2 - — ESP-AT 用户指南 latest 文档可得我们就把USART2设置为115200的波特率并且BufferSize写死为256。AT命令涉及到的特殊字符需要转义处理AT透传推荐串口使用空闲中断DMA模式USART2的RX通道和DMA0的CH2相连DMA需要偏移4个字节访问驱动层下面先实现驱动层代码串口需要用空闲中断DMA模式封装成结构体有#include stdint.h #include stdio.h #include stdbool.h #include string.h #include gd32f30x.h #include delay.h #define USART2_DATA_ADDR (USART2 0x04) //串口2的数据寄存器十六进制地址值 #define MAX_BUF_SIZE 256 #define WIFI_DISABLE gpio_bit_reset(GPIOG, GPIO_PIN_7) #define WIFI_ENABLE gpio_bit_set(GPIOG, GPIO_PIN_7) static uint8_t g_recvDataBuf[MAX_BUF_SIZE]; static uint16_t g_recvDataLen; typedef struct { uint32_t uartNo; rcu_periph_enum rcuUart; rcu_periph_enum rcuGpio; uint32_t gpio; uint32_t txPin; uint32_t rxPin; uint8_t irq; uint32_t dmaNo; rcu_periph_enum rcuDma; dma_channel_enum dmaCh; } UartHwInfo_t; // static UartHwInfo_t g_uartHwInfo {USART2, RCU_USART2, RCU_GPIOB, GPIOB, GPIO_PIN_10, // GPIO_PIN_11, USART2_IRQn, DMA0, RCU_DMA0, DMA_CH2}; static UartHwInfo_t g_uartHwInfo { .uartNo USART2, .rcuUart RCU_USART2, .rcuGpio RCU_GPIOB, .gpio GPIOB, .txPin GPIO_PIN_10, .rxPin GPIO_PIN_11, .irq USART2_IRQn, .dmaNo DMA0, .rcuDma RCU_DMA0, .dmaCh DMA_CH2, };IO口初始化G7配置为推挽输出控制模组使能TX复用推挽RX上拉输入static void WifiGpioInit(void) { rcu_periph_clock_enable(RCU_GPIOG); gpio_init(GPIOG, GPIO_MODE_OUT_PP, GPIO_OSPEED_2MHZ, GPIO_PIN_7); rcu_periph_clock_enable(g_uartHwInfo.rcuGpio); gpio_init(g_uartHwInfo.gpio, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, g_uartHwInfo.txPin); gpio_init(g_uartHwInfo.gpio, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, g_uartHwInfo.rxPin); }串口透传WIFI指令分为下面几步①唤醒外设时钟②复位USART③设置波特率这里传递115200③使能TEN\REN寄存器④使能串口接收空闲中断⑤置位UEN位使能USART。static void WifiUartInit(uint32_t baudRate) { /* 使能UART时钟*/ rcu_periph_clock_enable(g_uartHwInfo.rcuUart); /* 复位UART*/ usart_deinit (g_uartHwInfo.uartNo); /* 通过USART_CTL0寄存器的WL设置字长*/ //usart_word_length_set(g_uartHwInfo.uartNo, USART_WL_8BIT); /* 通过USART_CTL0寄存器的PCEN设置校验位*/ //usart_parity_config(g_uartHwInfo.uartNo, USART_PM_NONE); /* 在USART_CTL1寄存器中写STB[1:0]位来设置停止位的长度*/ //usart_stop_bit_set(g_uartHwInfo.uartNo, USART_STB_1BIT); /* 在USART_BAUD寄存器中设置波特率*/ usart_baudrate_set(g_uartHwInfo.uartNo, baudRate); /* 在USART_CTL0寄存器中设置TEN位使能发送功能*/ usart_transmit_config(g_uartHwInfo.uartNo, USART_TRANSMIT_ENABLE); /* 在USART_CTL0寄存器中设置REN位使能接收功能*/ usart_receive_config(g_uartHwInfo.uartNo, USART_RECEIVE_ENABLE); /* 使能串口接收空闲中断*/ usart_interrupt_enable(g_uartHwInfo.uartNo, USART_INT_IDLE); /* 使能串口中断*/ nvic_irq_enable(g_uartHwInfo.irq, 0, 0); /* 在USART_CTL0寄存器中置位UEN位使能UART*/ usart_enable(g_uartHwInfo.uartNo); }复习DMA配置流程注意方向是外设到CPU将数据从串口的数据寄存器偏移0x04搬运到全局数组之中即可static void WifiDmaInit(void) { /* 使能DMA时钟*/ rcu_periph_clock_enable(g_uartHwInfo.rcuDma); /* 复位DMA通道*/ dma_deinit(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh); dma_parameter_struct dmaStruct; /* 配置传输方向*/ dmaStruct.direction DMA_PERIPHERAL_TO_MEMORY; /* 配置数据源地址*/ dmaStruct.periph_addr USART2_DATA_ADDR; /* 配置源地址是固定的还是增长的*/ dmaStruct.periph_inc DMA_PERIPH_INCREASE_DISABLE; /* 配置源数据传输位宽*/ dmaStruct.periph_width DMA_PERIPHERAL_WIDTH_8BIT; /* 配置数据目的地址*/ dmaStruct.memory_addr (uint32_t)g_recvDataBuf; /* 配置目的地址是固定的还是增长的*/ dmaStruct.memory_inc DMA_MEMORY_INCREASE_ENABLE; /* 配置目的数据传输位宽*/ dmaStruct.memory_width DMA_MEMORY_WIDTH_8BIT; /* 配置数据传输最大次数*/ dmaStruct.number MAX_BUF_SIZE; /* 配置DMA通道优先级*/ dmaStruct.priority DMA_PRIORITY_HIGH; dma_init(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh, dmaStruct); /* 使能UART接收数据使用DMA*/ usart_dma_receive_config(g_uartHwInfo.uartNo, USART_RECEIVE_DMA_ENABLE); /* 使能DMA通道*/ dma_channel_enable(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh); }IDLE空闲中断的核心就是实现下面的中断服务函数void USART2_IRQHandler(void) { if (usart_interrupt_flag_get(g_uartHwInfo.uartNo, USART_INT_FLAG_IDLE) ! RESET) { usart_interrupt_flag_clear(g_uartHwInfo.uartNo, USART_INT_FLAG_IDLE); //第一步读取stat0寄存器清除IDLE标志位 usart_data_receive(g_uartHwInfo.uartNo); //第二步读取数据寄存器 g_recvDataLen MAX_BUF_SIZE - dma_transfer_number_get(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh); memset(g_recvDataBuf[g_recvDataLen], 0, MAX_BUF_SIZE - g_recvDataLen); printf(uart recv str:%s\n, g_recvDataBuf); //反面教材中断里面用了printf dma_channel_disable(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh); dma_transfer_number_config(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh, MAX_BUF_SIZE); dma_channel_enable(g_uartHwInfo.dmaNo, g_uartHwInfo.dmaCh); } }串口每收到一个字节由 DMA 自动搬进 g_recvDataBuf当一帧数据发送完毕、串口检测到总线空闲(超过 1 字节时间没新数据)时触发 USART2_IRQHandler在中断里计算出收到了多少字节。分行解读步骤如下①先确认触发源是 IDLE 中断USART2 中断还可能来自其他源先判断标志。②清除 IDLE 标志。手册规定 IDLE 位必须用先读状态寄存器、再读数据寄存器的顺序才能清掉所以这里 clear data_receive 两步配合使用。③算接收长度。DMA 初始化时把传输次数设为 MAX_BUF_SIZE(256)每搬一个字节该计数减 1所以 剩余计数 dma_transfer_number_get(...)已收长度 总数 − 剩余。④把缓冲区这次没用到的尾部清零保证 g_recvDataBuf 能当 C 字符串安全使用清掉上一帧残留。⑤打印结果。注释已说明——中断里调 printf 是反面教材printf 走串口发送、会阻塞、有重入风险、可能丢数据。⑥重新初始化 DMA为下一帧接收做准备。因为这里是普通(非循环)模式需要关通道→重设传输次数(256)→开通道相当于复位接收窗口。应用层用状态机避免死等static WifiCommState_t AtCmdHandle(char *cmd, char *rsp, uint32_t timeoutMs) { static WifiCommState_t s_commState WIFI_COMM_OK; static uint64_t s_sendCmdTime; char *recvStrBuf; if (s_commState ! WIFI_COMM_WAIT) { if (cmd ! NULL) { SendWifiModuleStr(cmd); } s_commState WIFI_COMM_WAIT; s_sendCmdTime getSysRunTime(); } else { if ((getSysRunTime() - s_sendCmdTime) timeoutMs) { recvStrBuf RecvWifiModuleStr(); if (strstr(recvStrBuf, rsp) ! NULL) { s_commState WIFI_COMM_OK; } } else { s_commState WIFI_COMM_FAIL; } } return s_commState; }21.3 基于状态机搭建程序框架每10ms调用一次下面的函数①模组初始化由单条查询改为两步配置 状态机旧逻辑只发 ATCWMODE? 查询。新逻辑ATE0关闭回显→ ATCWMODE1设 Station 模式。CheckWifiModuleWork() 用 AtCheckModuleCmdType 枚举 cmdType 静态变量驱动逐步执行返回 OK/FAIL/WAIT 三态而非之前的同步阻塞。②新增 CheckWifiConnect()硬编码连接指定 2.4G WifiSSID/PWD 写死为 HUAWEI-R1CMF4_2.4G / ThreadxZWJ1024ARM。用 sprintf 拼 ATCWJAP%s,%s等待 GOT IP超时 15s最多重试 3 次。③新增顶层状态机 WifiWorkState_t 驱动 WifiNetworkTask()CHECK_WIFI_MODULE - CHECK_WIFI_CONNECT - CONNECT_MQTT_SERVER - COMM_MQTT_SERVER | (FAIL) (预留) v HWRESET_WIFI_MODULE(最多1次) - WIWI_MODULE_ERROR(放弃)wifi_app.c:#include stdint.h #include stdio.h #include stdbool.h #include string.h #include systick.h #include wifi_drv.h #include sensor_drv.h #include delay.h #include wifi_app.h typedef enum { WIFI_COMM_WAIT, WIFI_COMM_OK, WIFI_COMM_FAIL, } WifiCommState_t; static WifiCommState_t AtCmdHandle(char *cmd, char *rsp, uint32_t timeoutMs) { static WifiCommState_t s_commState WIFI_COMM_OK; static uint64_t s_sendCmdTime; char *recvStrBuf; if (s_commState ! WIFI_COMM_WAIT) { if (cmd ! NULL) { SendWifiModuleStr(cmd); } s_commState WIFI_COMM_WAIT; s_sendCmdTime getSysRunTime(); } else { if ((getSysRunTime() - s_sendCmdTime) timeoutMs) { recvStrBuf RecvWifiModuleStr(); if (strstr(recvStrBuf, rsp) ! NULL) { s_commState WIFI_COMM_OK; } } else { s_commState WIFI_COMM_FAIL; } } return s_commState; } typedef struct { /* 要发送的AT命令 */ char *cmd; /* 期望的应答数据默认处理匹配到该字符串认为命令执行成功 */ char *rsp; /* 得到应答的超时时间达到超时时间为执行失败单位ms*/ uint32_t timeoutMs; } AtCmdInfo_t; /*模组初始化命令集*/ static AtCmdInfo_t g_checkModuleCmdTable[] { { .cmd ATE0\r\n, // 关闭回显 .rsp OK, .timeoutMs 1000, }, { .cmd ATCWMODE1\r\n, // 设置为Station模式 .rsp OK, .timeoutMs 1000, }, }; typedef enum { AT_E0 0, AT_CWMODE_1, } AtCheckModuleCmdType; WifiCommState_t CheckWifiModuleWork(void) { WifiCommState_t commState; static uint8_t retryCount 0; static AtCheckModuleCmdType cmdType AT_E0; switch (cmdType) { case AT_E0: commState AtCmdHandle(g_checkModuleCmdTable[AT_E0].cmd, g_checkModuleCmdTable[AT_E0].rsp, g_checkModuleCmdTable[AT_E0].timeoutMs); if (commState WIFI_COMM_OK) { retryCount 0; cmdType AT_CWMODE_1; } else if (commState WIFI_COMM_FAIL) { retryCount; if (retryCount 3) { retryCount 0; return WIFI_COMM_FAIL; } } break; case AT_CWMODE_1: commState AtCmdHandle(g_checkModuleCmdTable[AT_CWMODE_1].cmd, g_checkModuleCmdTable[AT_CWMODE_1].rsp, g_checkModuleCmdTable[AT_CWMODE_1].timeoutMs); if (commState WIFI_COMM_OK) { cmdType AT_E0; return WIFI_COMM_OK; } else if (commState WIFI_COMM_FAIL) { return WIFI_COMM_FAIL; } break; } return WIFI_COMM_WAIT; } static AtCmdInfo_t g_ConnectApCmdTable[] { { .cmd ATCWJAP\%s\,\%s\\r\n, // 这里的\是给编译器用的 //.cmd ATCWJAP\HIKE_5F\\,2.4G\,\hike666666\\r\n, .rsp GOT IP, .timeoutMs 15000, }, }; typedef enum { AT_CWJAP_SSID_PWD, } AtConnectApCmdType; //硬编码自己能用的2.4GWifi static char g_apSsid[20] HUAWEI-R1CMF4_2.4G; static char g_apPwd[20] ThreadxZWJ1024ARM; WifiCommState_t CheckWifiConnect(void) { WifiCommState_t commState; static AtConnectApCmdType cmdType AT_CWJAP_SSID_PWD; static uint8_t retryCount 0; char cmdStrBuf[256]; switch (cmdType) { case AT_CWJAP_SSID_PWD: sprintf(cmdStrBuf, g_ConnectApCmdTable[AT_CWJAP_SSID_PWD].cmd, g_apSsid, g_apPwd); commState AtCmdHandle(cmdStrBuf, g_ConnectApCmdTable[AT_CWJAP_SSID_PWD].rsp, g_ConnectApCmdTable[AT_CWJAP_SSID_PWD].timeoutMs); if (commState WIFI_COMM_OK) { retryCount 0; return WIFI_COMM_OK; } else if (commState WIFI_COMM_FAIL) { retryCount; if (retryCount 3) { retryCount 0; return WIFI_COMM_FAIL; } } break; } return WIFI_COMM_WAIT; } typedef enum { CHECK_WIFI_MODULE, CHECK_WIFI_CONNECT, CONNECT_MQTT_SERVER, COMM_MQTT_SERVER, HWRESET_WIFI_MODULE, WIWI_MODULE_ERROR, } WifiWorkState_t; void WifiNetworkTask(void) { WifiCommState_t commState; static WifiWorkState_t workState CHECK_WIFI_MODULE; static uint8_t hwresetCnt 0; switch (workState) { case CHECK_WIFI_MODULE: commState CheckWifiModuleWork(); if (commState WIFI_COMM_OK) { workState CHECK_WIFI_CONNECT; } else if (commState WIFI_COMM_FAIL) { workState HWRESET_WIFI_MODULE; } break; case CHECK_WIFI_CONNECT: commState CheckWifiConnect(); if (commState WIFI_COMM_OK) { workState CONNECT_MQTT_SERVER; } else if (commState WIFI_COMM_FAIL) { workState CHECK_WIFI_MODULE; } break; case CONNECT_MQTT_SERVER: break; case COMM_MQTT_SERVER: break; case HWRESET_WIFI_MODULE: if (hwresetCnt 1) // 如果AT命令不通硬件复位1次 { HwresetWifiModule(); DelayNms(1000); workState CHECK_WIFI_MODULE; hwresetCnt; } else { printf(wifi module error!\n); workState WIWI_MODULE_ERROR; // 如果硬件复位1次AT命令还是不通就不再执行WIFI任务的业务逻辑直接退出避免影响其他任务 } break; default: break; } }