EC20 4G模块可以通过串口和USB去驱动，但是串口速度比较慢，所以通过USB驱动才能提高通信速率。
硬件连接:
STM32F407:
EC20模块：
部分参考代码：
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_host.h"
#include "usbh_def.h"
#include "usbh_cdc.h"
#include "string.h"
UART_HandleTypeDef huart1;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);
void MX_USB_HOST_Process(void);
unsigned char recData[100];
unsigned int recLen;
void delay_ums(unsigned int i)
{
unsigned int cnt;
while(i--)
{
cnt=33500;
while(cnt--);
}
}
extern USBH_HandleTypeDef hUsbHostFS;
int main(void)
{
unsigned int a;
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_USART1_UART_Init();
MX_USB_HOST_Init();
MX_GPIO_Init();
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_0, GPIO_PIN_SET);
delay_ums(1000);
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_0, GPIO_PIN_RESET);
while (1)
{
/* USER CODE END WHILE */
MX_USB_HOST_Process();
delay_ums(1);
a++;
if(a>1000)
{
a=0;
USBH_CDC_Transmit(&hUsbHostFS, "AT\r\n", strlen("AT\r\n"));
}
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {
0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {
0};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 4;
RCC_OscInitStruct.PLL.PLLN = 168;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 7;
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_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief USART1 Initialization Function
* @param None
* @retval None
*/
static void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
/* USER CODE END USART1_Init 2 */
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {
0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOC_CLK_ENABLE();
/*Configure GPIO pin Output Level */
/*Configure GPIO pin : PA15 */
GPIO_InitStruct.Pin = GPIO_PIN_15;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_15, GPIO_PIN_SET);
/*Configure GPIO pin : PA15 */
GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_2;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_0|GPIO_PIN_2, GPIO_PIN_RESET);
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
void USBH_CDC_ReceiveCallback(USBH_HandleTypeDef *phost)
{
recLen = USBH_CDC_GetLastReceivedDataSize(phost);
HAL_UART_Transmit_IT(&huart1 ,(uint8_t*)recData,recLen);
while(__HAL_UART_GET_FLAG(&huart1,UART_FLAG_TC)!=SET); //等待发送结束
memset(recData,0x00,sizeof(recData));
}
注意点：
移远EC20模块连接后，配置描述符下一共有5个 Interface , 并且 Interface 中至多有3个Endpoint(下面简称Ep)。所以 注意： USBH_MAX_NUM_ENDPOINTS 需配置 >3 , USBH_MAX_NUM_INTERFACES 需配置 >5 。
* 注:
* cubemx生成的例程中,标准的CDC类设备,1个配置描述符中需要2接口其中一个为Communication Interface Class, 该接口需要一个方向为in的Ep另外一个为Data Interface Class, 该接口需要一个方向为in的Ep和一个方向为out的Ep所以USBH_CDC_InterfaceInit函数,调用了两次USBH_FindInterface函数查找两个匹配的Interface, 分别进行配置USB-TTL串口工具,debug状态下查询设备描述符结构体中,只有一个接口但是该接口拥有3个Ep, 2个方向为in, 1个方向为out.由此猜测,串口工具并没有将Interface分开经测试, Communication Interface使用的Ep为2, Data Interface使用Ep0,1。Ec20模块,可以读到5个Interface,但是只有Interface 1 2 3 有3个Ep,0 和 4 只有2个Ep。经测试,接口AT指令的串口Interface为 2.Interface 2中,Communication Interface使用的Ep为0 Data Interface使用的Ep为1 和 2。