usb-cdc issues

[Kanken6174]

Hi, i've successfully built and used the "SimulateCDC" example, but it has a few issues:

• It forces you to connect two hardware uarts together externally which is a bit silly (if possible i'd like to just be able to fill the TX buffer manually... no need for DMA)
• It doesn't work if the wired connection is not stopped. In my experience if i connect UART1 and 2 together nothing happens, but if i disconnect and reconnect the wires it does send its current buffer through the usb cdc, i have no idea why or how this happens but it just does...?

Please advise on how i could get this to work in a smoother way or if better, more recent samples exist.

[Kanken6174]

Bypassing this check solved the second issue for me, it now does send data to my computer, even if slowly.

[Kanken6174]

this quick little hack lets me write data without UART1 and 2 being physically wired together:

void DDWrite(const char* str, unsigned int len){
    for(int i = 0; i < len && i < DEF_UARTx_TX_BUF_LEN; i++){
        UART2_Rx_Buf[i] = str[i];
    }
    UARTx_Rx_DMALastCount = len-1;
    UARTx_Rx_DMACurCount = len;
}

usage:

int main(void)
{
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
    SystemCoreClockUpdate();
    Delay_Init();
    USART_Printf_Init(115200);

    RCC_Configuration( );
    TIM2_Init( );
    UART2_Init( 1, DEF_UARTx_BAUDRATE, DEF_UARTx_STOPBIT, DEF_UARTx_PARITY );

    Set_USBConfig();
    USB_Init();
    USB_Interrupts_Config();

    printf("SystemClk:%d\r\n",SystemCoreClock);
    printf( "ChipID:%08x\r\n", DBGMCU_GetCHIPID() );
    printf("USBD SimulateCDC Demo\r\n");
    unsigned int ctr = 0;
    unsigned int cpt = 0;
    const char hello_world[] = "Hello, world!\n";
    while(1)
    {
        if(ctr >= 10000){
            DDWrite(hello_world, 14);
            ctr = 0;
            cpt++;
        }
        UART2_DataRx_Deal( );
        UART2_DataTx_Deal( );
        ctr++;
    }
}