Jurgis Jurksta

Important changes to forums and questions

All forums and questions are now archived. To start a new conversation or read the latest updates go to forums.mbed.com.

10 years, 10 months ago.

Possibly buggy firmware for LPCXpresso 1549 and 11U68

Hi,

Where is the source code for lpc4322 firmware for those 2 boards? http://developer.mbed.org/teams/NXP/wiki/Updating-LPCXpresso-firmware

I suspect a bug in USB Serial part in the firmware. When I send back what I receive on those 2 boards, the last char either is not sent back or something else is sent back. I tried with another USB Serial on a different port and it was working OK. The problem starts when 3 or more bytes are sent, afterwards if I send 1 byte, I do not get back anything.

Sample application for LPC1159 (I used mbed-src library because I was debugging)

#include "mbed.h"

Serial pc1(USBTX, USBRX);
Serial pc2(P0_9, P0_29);
Serial pc3(P0_0, P1_3);

int main()
{
    pc1.baud(115200);
    pc1.printf("\r\nPC1: Serial Echo Server - 115200\r\n");
    
    pc2.baud(115200);
    pc2.printf("\r\nPC2: Serial Echo Server - 115200\r\n");
    
    pc3.baud(115200);
    pc3.printf("\r\nPC3: Serial Echo Server - 115200\r\n");
    
    while(1)
    {
        if (pc1.readable())
            pc1.putc(pc1.getc());
            
        if (pc2.readable())
            pc2.putc(pc2.getc());

        if (pc3.readable())
            pc3.putc(pc3.getc());
    }
}

Output on port 1

<<< \x0D\x0APC1: Serial Echo Server - 115200\x0D\x0A
>>> 1
<<< 1
>>> 12
<<< 12
>>> 123
<<< 12?
>>> 1
>>> 12
<<< 12

Output on port 2

<<< \x0D\x0APC2: Serial Echo Server - 115200\x0D\x0A
>>> 1
<<< 1
>>> 12
<<< 12
>>> 123
<<< 123
>>> 1
<<< 1
>>> 12
<<< 12

Output on port 3

\x0D\x0APC3: Serial Echo Server - 115200\x0D\x0A
>>> 1
<<< 1
>>> 12
<<< 12
>>> 123
<<< 123
>>> 1
<<< 1
>>> 12
<<< 12

I hope this demonstrates the issue.

Cheers, Jurgis

Most likely it is buffer overflow. 3 bytes per port buffer seems too small. Did you try one port first and slowly increase the number of bytes sent?

posted by HM Yoong 14 Apr 2015

Yes, I tried lots of things during 2 days when I tried to find the problem in mbed library. And came to concludion that the bug is in the firmware. I will not spend any more time on this, will use another usb to serial converter and another port if necessary.

posted by Jurgis Jurksta 15 Apr 2015

1 Answer

Martin Kojtal
10 years, 10 months ago.

Please look at https://github.com/ARMmbed/CMSIS-DAP

Accepted Answer

Looks like it is too complicated for me, I'll create an issue on github.

posted by Jurgis Jurksta 13 Apr 2015