Hi Regis,
USB CDC Host example is coded to work only with the USB CDC device example. Let me explain.
- USB CDC Device example receives data from UART - CDC and sends it back (echo) to CDC - UART
- USB CDC Host example send data to the device and waits for the echo. If the same amount of data that was transmited is not received the example will get stuck. You can see this part of the code in void CDC_Task () defined in cdc_serial.c.
/* Write data to USB */
if (uart2usb_num)
{
num_done = _io_cdc_serial_write(f_usb, uart2usb, (int_32)(sizeof(uart2usb[0]) * uart2usb_num));
if(num_done > 0)
{
for (i = (uint_32)num_done; i < uart2usb_num; i++) /* move buffer data, remove the written ones */
uart2usb[i - num_done] = uart2usb[i];
uart2usb_num -= num_done;
char_to_recv += num_done;
}
}
/* Read data from USB */
if(char_to_recv > 0)
{
num_done = _io_cdc_serial_read(f_usb, usb2uart + usb2uart_num, (int_32)(sizeof(uart2usb) / sizeof(uart2usb[0]) - usb2uart_num));
if(num_done > 0)
{
usb2uart_num += num_done;
if(char_to_recv >= num_done)
{
char_to_recv -= num_done;
}
else
{
char_to_recv = 0;
}
}
else
{
char_to_recv = 0;
}
}
/* write them to UART */
if (usb2uart_num > 0)
{
for (i = 0; i < usb2uart_num; i++)
{
#ifdef MCU_mcf51jf128
printf(" --received--> %c\n\r",usb2uart[i]);
#else
sci2_PutChar(usb2uart[i]);
#endif
}
usb2uart_num = 0;
}
}
I hope this helps.
Best regards,
Carlos
Technical Support Engineer
