Receiving Data Using the UART CORTEX M0

I  forgot to ask something else, I send data through the uart to the PC and

the PC responds sending some other data, well after I send the data, my LPC

seems to stop working, it doesn't respond anymore, why that happens?.

2015-01-13 9:32 GMT-04:30 Alejandra Angulo Rico <alerico90@gmail.com>:

I am using a ARM M0 Cortex LPC1114, let me check the baud rate to see if

that's the problem. Thank you!

2015-01-13 8:44 GMT-04:30 jensbauer <community@arm.com>:

       

>> <http://community.arm.com/?et=watches.email.thread>     Receiving Data

>> Using the UART CORTEX M0

>>

>> reply from jensbauer

>> <http://community.arm.com/people/jensbauer?et=watches.email.thread> in *ARM

>> Processors* - View the full discussion

>> <http://community.arm.com/message/24308?et=watches.email.thread#24308>

>>

I  forgot to ask something else, I send data through the uart to the PC and

the PC responds sending some other data, well after I send the data, my LPC

seems to stop working, it doesn't respond anymore, why that happens?.

2015-01-13 9:32 GMT-04:30 Alejandra Angulo Rico <alerico90@gmail.com>:

I am using a ARM M0 Cortex LPC1114, let me check the baud rate to see if

that's the problem. Thank you!

2015-01-13 8:44 GMT-04:30 jensbauer <community@arm.com>:

       

>> <http://community.arm.com/?et=watches.email.thread>     Receiving Data

>> Using the UART CORTEX M0

>>

>> reply from jensbauer

>> <http://community.arm.com/people/jensbauer?et=watches.email.thread> in *ARM

>> Processors* - View the full discussion

>> <http://community.arm.com/message/24308?et=watches.email.thread#24308>

>>

Looking at the code snippet you posted, I think your 'while(1)' could be the problem.

-But something is wrong with the snippet; it does not contain a balanced set of curly braces, so it's difficult to guess where they are in your original code.

You should make sure that there is a starting brace right after your 'while(1)'

For instance...

int main(void)

{

  // some initialization code here.

  while(1)

  {

     // your code here.

  }

// no code here.

}

Notice: the 'extern' keyword in front of 'int main(void)' should also be removed.

well, this is the main function

extern int main( void )

{

EVENT_T evt;

//SysTick_Config(SystemFrequency/100000);

// No se utliza OSTimeDly en esta sección

__disable_irq();

system_init();

if(1)

{//uint8_t buf[6];

uint8_t buf[SPEC12832RowNum*SPEC12832ColumnNum/8];

uint8_t c;

SPEC12832Select(LCD_SELECT_USER | LCD_SELECT_CUSTOM);

memset(buf, 0x00, sizeof(buf));

SPEC12832DisplayPattern(buf);

memset(screen1,'0',sizeof(screen1));

while(1)

{

//KeyScanProc(buf,screen1);

if ((value = uart0Getch()) >= 0)

{ screen1[1]=value;

send_to_uart(screen1,3);

uart0TxFlush();

}

}

}

}

However I run the program and after sending data several times the program

stops working,

2015-01-13 10:12 GMT-04:30 jensbauer <community@arm.com>:

       

<http://community.arm.com/?et=watches.email.thread>     Receiving Data

Using the UART CORTEX M0

reply from jensbauer

<http://community.arm.com/people/jensbauer?et=watches.email.thread> in *ARM

Processors* - View the full discussion

<http://community.arm.com/message/24326?et=watches.email.thread#24326>

OK, then we know this happens inside the while(1){ ... } loop, because we never leave the while loop.

We also know that it won't happen inside uart0Getch, as there are no loops in there.

So two functions are left:

send_to_uart and uart0TxFlush.

What do those two subroutines look like ?

these are thesub routines

int uart0Getch(void)

{

  if (LPC_UART->LSR & LSR_RDR)

{ return LPC_UART->RBR;

}

  return -1;

}

void uart0TxFlush(void)

{

  LPC_UART->FCR |= (1 << 2);          // Borra TX FIFO

}

2015-01-13 11:10 GMT-04:30 jensbauer <community@arm.com>:

       

<http://community.arm.com/?et=watches.email.thread>     Receiving Data

Using the UART CORTEX M0

reply from jensbauer

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<http://community.arm.com/message/24328?et=watches.email.thread#24328>

Have you tried not calling uart0TxFlush ?

(it should not be necessary to flush the outgoing data, and is not recommended).

Ok, let me try that and see if it works. Thanks for all!

2015-01-13 12:45 GMT-04:30 jensbauer <community@arm.com>:

       

<http://community.arm.com/?et=watches.email.thread>     Receiving Data

Using the UART CORTEX M0

reply from jensbauer

<http://community.arm.com/people/jensbauer?et=watches.email.thread> in *ARM

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<http://community.arm.com/message/24330?et=watches.email.thread#24330>

Just in case you were wondering why flushing is probably not what you want:

fflush(stdout); for printf will send all cached characters to the current output device.

flushing the transmit-buffer in a UART, means to throw away any data that has not yet been sent.

That means if you send the string:

"Hello World"

and you flush the transmit-buffer immediately after, you'll probably end up receiving only the first few charaters, perhaps only "He" or "Hel".

Yes, in fact I just ran the program with the flush function and the output

was something like: "HEL W". Thank you very much for your help!!! It has

been very useful

2015-01-13 15:32 GMT-04:30 jensbauer <community@arm.com>:

       

<http://community.arm.com/?et=watches.email.thread>     Receiving Data

Using the UART CORTEX M0

reply from jensbauer

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<http://community.arm.com/message/24333?et=watches.email.thread#24333>