本文实验将USB配置为虚拟串口。

一、FSP configration

添加r_usb_pcdc

为USB配置48Mhz

pins->USB_FS0->Operation Mode:Device

设置CDC描述符名称

二、软件部分

1、复制一份CDC描述符文件到src

https://gitee.com/ramcu/ra-fsp-examples/tree/master/example_projects/ek_ra4m2/usb_pcdc/usb_pcdc_ek_ra4m2_ep/e2studio/src

复制r_usb_pcdc_descriptor.c到src

2、打开USB

/* Open USB instance */

    err = R_USB_Open (&g_basic0_ctrl, &g_basic0_cfg);

/* Handle error */

if (FSP_SUCCESS != err)

    {

/* Turn ON RED LED to indicate fatal error */



        APP_ERR_TRAP(err);

    }

3、USB事件处理

char firstPage[]="press 1 for Led 1\r\n";

char secondPage[]="press 2 for Led 2\r\n";

while (true)

    {

/* Obtain USB related events */

        err = R_USB_EventGet (&event_info, &usb_event);



/* Handle error */

if (FSP_SUCCESS != err)

        {

/* Turn ON RED LED to indicate fatal error */



            APP_ERR_TRAP(err);

        }



/* USB event received by R_USB_EventGet */

switch (usb_event)

        {

case USB_STATUS_CONFIGURED:

            {

                err = R_USB_Read (&g_basic0_ctrl, g_buf, READ_BUF_SIZE, USB_CLASS_PCDC);

break;

            }



case USB_STATUS_READ_COMPLETE:

            {

if(b_usb_attach)

                {

                    err = R_USB_Read (&g_basic0_ctrl, g_buf, READ_BUF_SIZE, USB_CLASS_PCDC);

                }



/* Switch case evaluation of user input */

switch (g_buf[0])

                {

case KIT_INFO://2

                    {

                        print_to_console(firstPage);

                        R_IOPORT_PinWrite(&g_ioport_ctrl, BSP_IO_PORT_04_PIN_04, OFF);

                        R_IOPORT_PinWrite(&g_ioport_ctrl, BSP_IO_PORT_04_PIN_05, ON);

break;

                    }

case NEXT_STEPS://2

                    {

                        print_to_console(secondPage);

                        R_IOPORT_PinWrite(&g_ioport_ctrl, BSP_IO_PORT_04_PIN_04, ON);

                        R_IOPORT_PinWrite(&g_ioport_ctrl, BSP_IO_PORT_04_PIN_05, OFF);

break;

                    }



case CARRIAGE_RETURN:

                    {

/* Print banner info to console */

                        err = print_to_console(p_welcome);

if (FSP_SUCCESS != err)

                        {

/* Turn ON RED LED to indicate fatal error */



                            APP_ERR_TRAP(err);

                        }

break;

                    }



default:

                    {

break;

                    }

                }

break;

            }



caseUSB_STATUS_REQUEST : /* Receive Class Request */

            {

/* Check for the specific CDC class request IDs */

if (USB_PCDC_SET_LINE_CODING == (event_info.setup.request_type & USB_BREQUEST))

                {

                    err =  R_USB_PeriControlDataGet (&g_basic0_ctrl, (uint8_t *) &g_line_coding, LINE_CODING_LENGTH );

/* Handle error */

if (FSP_SUCCESS != err)

                    {

/* Turn ON RED LED to indicate fatal error */



                        APP_ERR_TRAP(err);

                    }

                }

elseif (USB_PCDC_GET_LINE_CODING == (event_info.setup.request_type & USB_BREQUEST))

                {

                    err =  R_USB_PeriControlDataSet (&g_basic0_ctrl, (uint8_t *) &g_line_coding, LINE_CODING_LENGTH );

/* Handle error */

if (FSP_SUCCESS != err)

                    {

/* Turn ON RED LED to indicate fatal error */



                        APP_ERR_TRAP(err);

                    }

                }

elseif (USB_PCDC_SET_CONTROL_LINE_STATE == (event_info.setup.request_type & USB_BREQUEST))

                {

                    err = R_USB_PeriControlStatusSet (&g_basic0_ctrl, USB_SETUP_STATUS_ACK);

/* Handle error */

if (FSP_SUCCESS != err)

//if (FSP_SUCCESS != g_err)

                    {

/* Turn ON RED LED to indicate fatal error */



                        APP_ERR_TRAP(err);

                    }

                }

else

                {

/* none */

                }



break;

            }



caseUSB_STATUS_DETACH:

caseUSB_STATUS_SUSPEND:

            {

                b_usb_attach = false;

memset (g_buf, 0, sizeof(g_buf));

break;

            }

caseUSB_STATUS_RESUME:

            {

                b_usb_attach = true;

break;

            }

default:

            {

break;

            }

        }

当串口收到1时，串口输出firstPage内容，并点亮led1
当串口收到2时，串口输出secondPage内容，并点亮led2

3、CDC串口输出函数

fsp_err_t print_to_console(char *p_data)

{

fsp_err_t err = FSP_SUCCESS;

uint32_t len = ((uint32_t)strlen(p_data));



    err = R_USB_Write (&g_basic0_ctrl, (uint8_t*)p_data, len, USB_CLASS_PCDC);

/* Handle error */

if (FSP_SUCCESS != err)

    {

return err;

    }



    err = check_for_write_complete();

if (FSP_SUCCESS != err)

    {

/* Did not get the event hence returning error */

returnFSP_ERR_USB_FAILED;

    }

return err;

}

staticfsp_err_tcheck_for_write_complete(void)

{

usb_status_t usb_write_event = USB_STATUS_NONE;

int32_t timeout_count = UINT16_MAX;

fsp_err_t err = FSP_SUCCESS;

usb_event_info_t    event_info = {0};



do

    {

        err = R_USB_EventGet (&event_info, &usb_write_event);

if (FSP_SUCCESS != err)

        {

return err;

        }



        --timeout_count;



if (0 > timeout_count)

        {

            timeout_count = 0;

            err = (fsp_err_t)USB_STATUS_NONE;

break;

        }

    }while(USB_STATUS_WRITE_COMPLETE != usb_write_event);



return err;

}

三、运行

串口输出