topic Re: CDC Send 128_bytes Failure in Kinetis Microcontrollers

CDC Send 128_bytes Failure

CCandido — Fri, 30 Dec 2016 13:07:08 GMT

Hi,

my system to test CDC Kinetis MK20DX256VLL7, with C# VS2013,

whats problems:

send frame 128 bytes ARM/ PC = ok

send frame 16 bytes PC/ARM = ok

send frame 32 bytes PC/ARM = OK..failures....OK

send frame 128 bytes PC/ARM = Many failures.

all buffers in arm = 128 bytes CDC1_DATA_BUFF_SIZE 128 and others.

simple test:

Visual Studio: serialPort1.Write( str_OutBuffer, 0, 128 ); // sendo to ARM

ARM:

loop:

if (CDC1_App_Task(cdc_buffer, sizeof(cdc_buffer))!=ERR_BUSOFF){

if (CDC1_GetCharsInRxBuf()!=0){ // if have bytes received <-------

lenth = CDC1_GetCharsInRxBuf(); get numbers bytes in buffer received

clear_bufstr( 128); //clear buffer + add ( '\0' )
val = bytetochar( lenth ); // convert byte to char(X2)
buf_str[0] = (byte) (val>>8);
buf_str[1] = (byte) (val);
buf_str[127]='#';
WAIT1_Waitms(5);
CDC1_SendString( buf_str); // send to PC = ok

}

results:

arm received: 0x20,0x80,0x40,0x60,0x10.....

how to maker protocols to frame 128 bytes ( char/2 = 64 bytes Hex )

thanks,

Carlos.

Re: CDC Send 128_bytes Failure

mjbcswitzerland — Mon, 02 Jan 2017 16:18:25 GMT

Hi Carlos

There are a few threads that may be related (I didn't find the one that I was hoping to find where there are also suggested workarounds for some problems, but you could spend some time searching more carefully):
https://community.nxp.com/message/814841
https://community.nxp.com/thread/385999?q=virtual%20com
https://community.nxp.com/message/621820

If you don't find a solution take a look at http://www.utasker.com/kinetis/TWR-K20D72M.html
which includes industrial quality USB-CDC operation proven on many Kinetis and Coldfire parts during 8 years of intensive service. Simple to use, allows multiple CDC interfaces at the same time (and multiple CDC to UART bridges with complete end-to-end flow control), plus CDC based RNDIS.
The complete operation can be simulated to allow reviews and accelerate product development.
http://www.utasker.com/docs/uTasker/uTaskerV1.3_USB_Demo.PDF
http://www.utasker.com/docs/uTasker/USB_User_Guide.PDF
http://www.utasker.com/docs/uTasker/uTaskerRNDIS.pdf

Regards

Mark

Re: CDC Send 128_bytes Failure

CCandido — Mon, 02 Jan 2017 19:56:41 GMT

Hi Mark,

Thank you for your suggestion, 16 bytes the packet does not give, it would be 16 every 10ms of intervals.
I tried to increase the buffer to 128 did not give it, but for 64 bytes it worked, so until there is a stack with a bigger package I will adapt with this one.

#undef CIC_NOTIF_ENDP_PACKET_SIZE
#define CIC_NOTIF_ENDP_PACKET_SIZE (64)
#undef DIC_BULK_IN_ENDP_PACKET_SIZE
#define DIC_BULK_IN_ENDP_PACKET_SIZE (64)/* max supported is 64 */
#undef DIC_BULK_OUT_ENDP_PACKET_SIZE
#define DIC_BULK_OUT_ENDP_PACKET_SIZE (64)/* max supported is 64*/

for error buffre < 64 bytes:

void timer_isr(void){ 1ms

if ( CDC1_GetCharsInRxBuf() < 64 ) // no read

return...

else

CDC1_GetChar....

-----

}

thanks,

Carlos.