Hello Raymond,
In CDC example, USB_Class_CDC_Send_Data function serves as sending host ack package as well as makes the looback function.
In your case, you need to send a NULL package only when data has been received (ACK package), try something like this:
void Virtual_Com_App(void) {
if ((0 != g_recv_size) && (0xFFFFFFFF != g_recv_size))
{
int32_t i;
/* Copy Buffer to Send Buff */
for (i = 0; i < g_recv_size; i++)
{
USB_PRINTF("Copied: %c\n\r", g_curr_recv_buf[i]);
}
g_recv_size = 0;
/* Send NULL data when package has been received */
USB_Class_CDC_Send_Data(g_app_handle, DIC_BULK_IN_ENDPOINT,
NULL, 0);
}
}
Other way, every time that Virtual_Com_app is called, you are trying to send a NULL data making endpoint to be busy and crashing application.
I made a simple test of this function and it seems to work fine (next image shows what i got on UART terminal (OpenSDA terminal)).
I hope this can help
Regards,
Isaac
Hello Raymond,
After a review on your code, i noticed that you are sending NULL package on every received data and then, once you received '\r' character, you try to send a string ("TEST"). Current demo structure needs to send NULL data only when there is not available data on device, otherwise, you should send these data to host.
For example, your current project sends both data (NULL and string):
As you can see, when device receives 0x0D, you send a NULL package (No data) and then send 5 bytes ("T E S T \0") bytes, this causes xD to get full after 9 attempts.
The right way to do this would be only send NULL package when you do not want to send data to host:
As you can see, after 0x0D is received, we send the string ("TEST") instead of NULL data and this works fine, otherwise, we send NULL data. Next is code used to get this functionality:
void Virtual_Com_App(void)
{
int c;
int received = 0, send_ack = 1;
/* User Code */
if ((0 != g_recv_size) && (0xFFFFFFFF != g_recv_size))
{
int32_t i;
for (i = 0; i < g_recv_size; i++)
{
if (g_curr_recv_buf[i] == '\r') {
send_ack = 0;
}
usb_if_vcom_put(g_curr_recv_buf[i]);
}
g_recv_size = 0;
if (send_ack) {
received = 1;
}
}
g_send_size = 0;
while ((c = usb_if_vcom_get()) != -1)
{
g_curr_send_buf[g_send_size++] = c;
if (g_send_size == DATA_BUFF_SIZE)
{
// buffer is full, send it and
// more bytes can be picked up on the next pass
break;
}
}
if (g_send_size)
{
uint8_t error;
uint32_t size = g_send_size;
g_send_size = 0;
error = USB_Class_CDC_Send_Data(*g_cdc_vcom_ptr, DIC_BULK_IN_ENDPOINT, g_curr_send_buf, size);
if (error != USB_OK)
{
/* Failure to send Data Handling code here */
}
}
else if (received == 1)
{
// Tell driver there is no data so it can flush output
USB_Class_CDC_Send_Data(*g_cdc_vcom_ptr, DIC_BULK_IN_ENDPOINT, NULL, 0);
}
return;
}
You only need to send NULL character when you are not willing to send data to host, otherwise, you need to send data to host.
I will investingate further on this and try to see why xd entries are not freed.
I hope this can helps,
Best Regards,
Isaac
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