STM32F030 and SPWF01 WiFi Module

[Tabulous]

Hi
i am currently working with the above aparts, and am experiencing serial data loss/corruption.

The interface to the WiFi module is a simple UART 115200 with hardware flow control. Module is controlled via AT commands.


All the AT command control works fine, as the data returned from the module is not large. 10-20 byte responses.


Now when i get the module to do a HTTP POST to webserver, the response to this is quite long, basically its the HTTP 200 OK crap you get back from a server, so it can be a good few 100 bytes.

The issue is the MCU is not getting everything correctly, i've checked if everything is coming out of the WiFi module TX pin Ok and it is.


Flow control is all enable as i can see the CTS line holding the WiFi off periodically. I've also increased the 'SERIAL_BUFFERS_SIZE' upto 128bytes in the halconf.h
I've tried changing the Threads priority, this made no difference.

This is my Thread code

Code: Select all

static THD_FUNCTION(ThreadAthl, arg)
{
msg_t c;
eventflags_t flags;
ATHND_ST *pd = &at;
event_listener_t elModemdata;


    (void)arg;
    chRegSetThreadName("athl");
    sdStart(&SD2, &serialconfig);

    /* Register thread watchdog */
//    watchdogRegister( APPWTDG_ATC );

    chEvtRegister(chnGetEventSource(&SD2),
                  &elModemdata, EVENT_MASK(1));

    while( TRUE )
    {
//        watchdogNotify( APPWTDG_ATC );

        flags = chEvtGetAndClearFlags(&elModemdata);

        if(flags & CHN_INPUT_AVAILABLE)
        {
           do
           {
              c = chnGetTimeout(&SD2, TIME_IMMEDIATE);

              if ( c != Q_TIMEOUT )
              {

                  switch( pd->service )
                  {
                      case DAT_MODE:
                          data_mode_handler( c );
                          break;

                      case CMD_MODE:
                          command_mode_handler( c );
                          break;
                  }

                  MBS_DEBUG( DBG_MASK_ATC, "%c", c );
              }
           }
           while ( c != Q_TIMEOUT );
        }

        chEvtWaitOneTimeout(EVENT_MASK(1), MS2ST(10));
    }

//    return( 0 );
}

This line just outputs what is received, and this does not match what is coming out of the WiFi Module TX pin
MBS_DEBUG( DBG_MASK_ATC, "%c", c );

What else can i look at ?

[Giovanni]

Hi,

Are you getting overflow event flags?

Giovanni

[Tabulous]

Hi,

Are you getting overflow event flags?

Giovanni

Should the flow control not stop this happening ?

Just added a check for overrun and yes it looks like this is hapening

[Giovanni]

There are two kind of overflows: data overflow (queue full) and ISR overflow.

Probably the ISR is not serviced fast enough. Move the USART IRQ priority to 3 and see if this helps. The default priority is very low and all other IRQs can preempt it.

Please also place breakpoints and see what kind of overflow you are getting.

Giovanni

[Tabulous]

There are two kind of overflows: data overflow (queue full) and ISR overflow.

Probably the ISR is not serviced fast enough. Move the USART IRQ priority to 3 and see if this helps. The default priority is very low and all other IRQs can preempt it.

Please also place breakpoints and see what kind of overflow you are getting.

Giovanni

By default its 3 anyways, as per define in mcuconf.h

#define STM32_SERIAL_USART2_PRIORITY 3

I put break on this this code and it never hits it

Code: Select all

static void set_error(SerialDriver *sdp, uint32_t isr) {
  eventflags_t sts = 0;

  if (isr & USART_ISR_ORE)
    sts |= SD_OVERRUN_ERROR;
  if (isr & USART_ISR_PE)
    sts |= SD_PARITY_ERROR;
  if (isr & USART_ISR_FE)
    sts |= SD_FRAMING_ERROR;
  if (isr & USART_ISR_NE)
    sts |= SD_NOISE_ERROR;
  osalSysLockFromISR();
  chnAddFlagsI(sdp, sts);
  osalSysUnlockFromISR();
}

but checking this in the thread

Code: Select all

        if(flags & SD_OVERRUN_ERROR)
        {
            MBS_DEBUG( DBG_MASK_ATC, "Overrun !\r\n" );
        }

results in being true

[Giovanni]

Hi,

There is another overflow case in the ISR, where the char is queued, set the breakpoint there too. If you hit that then the thread does not empty the queue fast enough and the received character cannot be queued. It means that the queue is full.

About the priority, sorry, 3 was for M3/M4/M7, on the M0 set it to 1 (highest).

Giovanni

[Tabulous]

Hi,

There is another overflow case in the ISR, where the char is queued, set the breakpoint there too. If you hit that then the thread does not empty the queue fast enough and the received character cannot be queued. It means that the queue is full.

About the priority, sorry, 3 was for M3/M4/M7, on the M0 set it to 1 (highest).

Giovanni

its hitting the chnAddFlagsI(sdp, SD_OVERRUN_ERROR); in this

Code: Select all

void sdIncomingDataI(SerialDriver *sdp, uint8_t b) {

  osalDbgCheckClassI();
  osalDbgCheck(sdp != NULL);

  if (iqIsEmptyI(&sdp->iqueue))
    chnAddFlagsI(sdp, CHN_INPUT_AVAILABLE);
  if (iqPutI(&sdp->iqueue, b) < Q_OK)
    chnAddFlagsI(sdp, SD_OVERRUN_ERROR);

[Giovanni]

Hi,

It means that the ISR is unable to put data in queue because the queue is full. This is cause by the queue not being emptied fast enough, check the thread that does that.

Giovanni

[Tabulous]

Hi,

It means that the ISR is unable to put data in queue because the queue is full. This is cause by the queue not being emptied fast enough, check the thread that does that.

Giovanni

my recieving thread is here

Code: Select all

static THD_FUNCTION(ThreadAthl, arg)
{
msg_t c;
eventflags_t flags;
ATHND_ST *pd = &at;
event_listener_t elModemdata;


    (void)arg;
    chRegSetThreadName("athl");
    sdStart(&SD2, &serialconfig);

    /* Register thread watchdog */
//    watchdogRegister( APPWTDG_ATC );

    chEvtRegister(chnGetEventSource(&SD2),
                  &elModemdata, EVENT_MASK(1));

    while( TRUE )
    {
//        watchdogNotify( APPWTDG_ATC );

        flags = chEvtGetAndClearFlags(&elModemdata);

        if(flags & SD_OVERRUN_ERROR)
        {
            MBS_DEBUG( DBG_MASK_ATC, "Overrun !\r\n" );
        }

        if(flags & CHN_INPUT_AVAILABLE)
        {
           do
           {
              c = chnGetTimeout(&SD2, TIME_IMMEDIATE);

              if ( c != Q_TIMEOUT )
              {

                  switch( pd->service )
                  {
                      case DAT_MODE:
                          data_mode_handler( c );
                          break;

                      case CMD_MODE:
                          command_mode_handler( c );
                          break;
                  }

//                  MBS_DEBUG( DBG_MASK_ATC, "%c", c );
              }
           }
           while ( c != Q_TIMEOUT );
        }

        chEvtWaitOneTimeout(EVENT_MASK(1), MS2ST(10));
    }

//    return( 0 );
}

i do have a this to wait for 10ms this might not help.......chEvtWaitOneTimeout(EVENT_MASK(1), MS2ST(10));

[Giovanni]

The timeout does not matter, it is the execution time of those handlers that you should verify. If you don't get data fast enough the queue will fill.

Giovanni