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USB Component
Version 6.12.8
MDK Middleware for USB Device and Host Communication
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This example application shows how to communicate with an USB CDC ACM Device from a microcontroller. It is a simple demonstration on how to send data from the USB Host to the attached USB CDC ACM Device. Here, the USB Host sends "Test!" to the USB CDC ACM Device and stores all incoming data from the device into the array receive_buf
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The following picture shows an exemplary connection of the development board and an USB CDC ACM Device implemented on another development board. This USB CDC ACM Device is connected to a PC via RS232 to check incoming messages.
Create a new project in MDK. In this example, we are using the MCBSTM32F400 board with the STM32F407IGHx device. In the Manage Run-Time Environment window, select the following components:
Click the Resolve button and then OK. Your Project should look like this:
#include <stdio.h> /* Standard I/O .h-file */ #include <ctype.h> /* Character functions */ #include <string.h> /* String and memory functions */ #include "cmsis_os2.h" /* CMSIS RTOS definitions */ #include "rl_usb.h" /* RL-USB function prototypes */ #include "Board_LED.h" #include "Driver_USART.h" #include "stm32f4xx_hal.h" /* UART Driver */ extern ARM_DRIVER_USART Driver_USART9; #define ptrUART_USB (&Driver_USART9) static uint8_t receive_buf[64]; extern uint32_t os_time; uint32_t HAL_GetTick(void) { return os_time; } /* System Clock Configuration */ void SystemClock_Config(void) { RCC_OscInitTypeDef RCC_OscInitStruct; RCC_ClkInitTypeDef RCC_ClkInitStruct; /* Enable Power Control clock */ __PWR_CLK_ENABLE(); /* The voltage scaling allows optimizing the power consumption when the device is clocked below the maximum system frequency (see datasheet). */ __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1); /* Enable HSE Oscillator and activate PLL with HSE as source */ 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 = 25; RCC_OscInitStruct.PLL.PLLN = 336; RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2; RCC_OscInitStruct.PLL.PLLQ = 7; HAL_RCC_OscConfig(&RCC_OscInitStruct); /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */ RCC_ClkInitStruct.ClockType = 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; HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5); } /*------------------------------------------------------------------------------ * UART Done Callback *----------------------------------------------------------------------------*/ void UART_Done (uint32_t event) { switch (event) { case ARM_USART_EVENT_SEND_COMPLETE: // All requested data was transmitted LED_On(1); break; case ARM_USART_EVENT_RECEIVE_COMPLETE: // After 64 bytes were received, restart new reception ptrUART_USB->Receive (receive_buf, 64); LED_On(2); break; } } /*------------------------------------------------------------------------------ * Application *----------------------------------------------------------------------------*/ int main (void) { static bool con_last = false; bool con; HAL_Init(); /* Initialize the HAL Library */ SystemClock_Config(); /* Configure the System Clock */ LED_Initialize (); USBH_Initialize (0); /* Initialize USB Host 0 */ while (1) { con = (USBH_CDC_ACM_GetDeviceStatus(0) == usbOK); if (con ^ con_last) { if (con) { con_last = true; LED_On(0); osDelay(1000); /* Initialize and configure UART <-> USB Bridge */ ptrUART_USB->Initialize (UART_Done); ptrUART_USB->PowerControl(ARM_POWER_FULL); ptrUART_USB->Control (ARM_USART_MODE_ASYNCHRONOUS | ARM_USART_DATA_BITS_8 | ARM_USART_PARITY_NONE | ARM_USART_STOP_BITS_1 | ARM_USART_FLOW_CONTROL_NONE , 115200 ); ptrUART_USB->Control (ARM_USART_CONTROL_TX, 1); ptrUART_USB->Control (ARM_USART_CONTROL_RX, 1); ptrUART_USB->Receive (receive_buf, 64); ptrUART_USB->Send ("Test!", 5); } else { con_last = false; LED_Off(0); } } else { if (con) { // Receive data can be checked by polling as callback will be called // only when all requested number of bytes were received // (in this case 64 bytes) if (ptrUART_USB->GetRxCount() == 5) { // If 5 bytes were received } } osDelay(1000); } } }
Before building the project, you need to edit these configuration files:
Before building and downloading the project to the target, make sure that the correct debugger is set in the Options for Target dialog (ALT + F7). You may then build and download the example project to the evaluation board using the µVision commands:
After these steps, the project should start executing on your evaluation kit. In case of errors, refer to the Evaluation Board User's Guide for configuration information.