UART PARITY ERROR with sleep mode

Hi Dhvani,

Could you paste in a minimal example of how to reproduce the issue? Setup, method for transmission, call to transmission etc. and I will try to reproduce it.

Best regards,
Aslak 

Hi Aslak,

In my application , I am running TI CC2541 as slave (Peripheral ) device in power saving mode with PAIRING and Bonding is enable. When my slave device is completely bounded with master device and then i am sending 0x02 command. Before putting command on UART UODBUF , we set  one IO pin to low for 40 ms and then we put data on U0DBUF , after that we keep IO pin to low for 12 ms.

  Please find here code which we are using for command transmission

#define SEND_IDLE    0
#define START_DELAY  1
#define SEND         2
#define STOP_DELAY   3

uint8 Buffer[128];
uint8 Tail=0;
volatile uint8 Head=0;
uint8 Delay = 0;    // in turms of ms
volatile uint8 flag = false;
volatile uint8 State = UART_SEND_IDLE;  // uart tx state flag


// an app function to write command in buffer for transmitt and exit

uint8 writeUARTCmd( uint8 cmd )
{
  Buffer[Tail] = cmd;
  
  if (Tail >= 128)
  {
    Tail = 0;
  }
  else
  {
    Tail++;
  }

  if(flag == false )   // if command on uart not seding set intr.
  {
    IEN2 |= UTX0IE;
  }
  osal_pwrmgr_task_state(TaskID, PWRMGR_HOLD);
  return SUCCESS;
}


// function set timer3 for delay.
void timer3(uint16 msdelay)
{
  Delay = msdelay;
  start timer3 for msdelay.
}


// UART0 tx ISR .
// First check is any data to send on UART  by checking Head and Tail
// If no data to send then disable UART tx intrrupt and set power in converse state.
// If there is data to send on UART 
// clear IF,  start TIMER 3 to 40 ms delay before actully data to put on UART U0DBUF register.
// Exit.

HAL_ISR_FUNCTION( halUART0TxIsr, UTX0_VECTOR )
{
  if(Head == Tail)
  {
    IEN2 &= ~UTX0IE; 
    osal_pwrmgr_task_state(TaskID, PWRMGR_CONSERVE);
  }

  else
  {
    if(flag == false )
    {
      flag = true;
      UTX0IF = 0;
      if(State == UART_SEND_IDLE )  // check UART state IDLE
      {
        State = UART_START_DELAY;  // state change to START_DELAY
        timer3(40); // Start timer3 for delay
      }
    }
  }
}



// Timer 3 ISR is called every 1ms second
// Decrement Delay counter 
// if Delay counter is zero.
// if UART state is UART_START_DELAY then call UARTSendCmd()
// else if state is UART_STOP_DELAY  then call UARTSendComplete()
HAL_ISR_FUNCTION( halTimer3Isr, T3_VECTOR )
{
  TIMIF &=  0xFE ;        // cler timer3 flag;
  T3CTL &= ~0x10;          //stop timer
  Delay--;
  if(Delay <= 0) {
    T3CTL |= 0x04;
    if(State == UART_START_DELAY ) {
      UARTSendCmd();
    }
    else if (State == UART_STOP_DELAY) {
      UARTSendComplete();
    }

  }
  else {
    T3CTL |= 0x10;       // start timer
  }
}


// Function put Data on UODBIF from local Buffer 
// And start timer3 for 12ms delay 
// Put state to UART_SEND
void UARTSendCmd()
{
  
  UTX0IF = 0;
  U0DBUF = txBuffer[uartTxHead];
  IEN2 &= ~UTX0IE;  
  State = UART_SEND;
  timer3(12);
}


// after 12ms delay
// set UART state to idle
// Enable UART tx interrupt and set interrupt flag true 
// So UART tx interrupt called again. 
void UARTSendComplete()
{
  Head++;
  if(Head >= 128)
  {
    Head = 0;
  }
  State = UART_SEND_IDLE;
  flag = false;
  IEN2 |= UTX0IE;
  UTX0IF = 1;
}

Thanks in Advance

Dhvani Patel

Hi,

What is the setup code that you use for the uart?

What's what on the scope picture?

Best regards,
Aslak 

Hi Aslak,

For reproduce this issue, you have to set up UART with 2400 baud rate , event parity , one stop bit. Now send  number commands on UART when paring and bounding complete callback call. and also send number of command on uart  when some event comes to slave from master , like proximately, unread, and some other .. . This issue is not reproducing every time. Its comes randomly.

Please look in above sample code for transmission and if i am missing something. Please provide your suggestion.

Thanks

Dhvani Patel

Hi,

Sorry that I was not specific. I would like to see your exact setup code to be able to reproduce it exactly, to see if there is something wrong with the setup, and to see which pins etc you are using. 

Where does the clock signal on the oscilloscope picture come from?

Best regards,
Aslak 

Hi Aslak

Here is my UART setup.

P1.4 -> Rx
p1.5 -> Tx

No Hardware flow control.

UART  setup:

PERCFG |= 0x01;                                                                                     // UART0 Alt.2
P1SEL  |= 0x30;                                                                                        // Enable Tx and Rx on P1.
ADCCFG &= ~0x30;                                                                                 // Make sure ADC doesnt use this.
U0CSR = CSR_MODE;                                                                           // Mode is UART Mode.
U0UCR = UCR_FLUSH ;                                                                        // Flush
U0BAUD = 59;                                                                                           // For 2400 baud rate
U0GCR = 6;                                                                                               // For 2400 baud rate
U0UCR =  UCR_D9 | UCR_BIT9 | UCR_PARITY | UCR_STOP;    // EVEN PARITY BIT , 9 bit transfer,  parity enable , High stop bit.
URX0IE = 1;                                                                                               // Set Receive Interrupt Enable Bit
UTX0IF = 1;                                                                                                // Set Transmit Interrupt Flag Bit
U0CSR = (CSR_MODE | CSR_RE);                                                    // UART mode with Receiver enable

In waveform 2nd wave show a TX wave with transmission delay about 5.28ms.

Regards,

Dhvani Patel

Hi

Please anyone can suggest me above configuration if i am wrong and provide me some input as i need its urgent.  ?

Thanks in Advanced,

Dhvani Patel

Hi Dhvani,

So I'm not really able to reproduce the error. Can you try to make the error occur outside of an active connection? I mean, to send a lot of packets when not advertising, not in a connection etc, and see if that ever fails. Just to isolate the problem a bit.

Aslak

Hi Aslak,

Thank you for looking in this issue.

This clock stretching problem occurs when my slave device is  in Advertising  mode  or in Pairing mode or in  connected mode with master and receive alerts from master . 

In a simple test, in which i am sending lots of commands on UART without Advertising , then its work fine.Please can you suggest me that this problem occurred due to some activity on RF ? And provide me some possible solution with same UART configuration. Waiting for your response .

Regards,

Dhvani Patel

Hi Harry,

Thanks for your suggestion.

If this is H/W bug in UART module then every time there is a parity error comes. But in my case,clock stretching issue comes inconsistent and it is occurred  when my slave device is  in active mode means in Advertising mode or in Pairing mode or in Connected mode with slave device and master sends some alert to slave.

Regards

Dhvani Patel

Hi Aslak,

Please find here image which show that command bit stretched during transmission when my slave device CC2541(peripheral)  is connected  with master device(Central).

Please provide me some solution. Is this a bug from TI or a valid scenario ?

Regards,

Dhvani Patel

Hi Harry,

I have tested this same things with disable POWER_SAVING macro and I am getting same result. 1) Sends lots of command  on UART when my device not in advertising any packet , I am  not getting any wrong command on UART receiver side. 2)   Sends lots of command  on UART when my device in Advertising mode , i am getting some wrong commands on other side of  UART  receiver.

Please you can try this simple test. Send 150 number of command in idle condition and in Advertising  mode.