CC2640R2F: UART misses bytes after debugguer pause

Hello,

Another device periodically sends 20 bytes of data to the CC2640R2F :

abcdefgh \r \n
01234567 \r \n

The sample code below just echoes back the incoming data :

// ****************************************************************************
// includes
// ****************************************************************************
#include <string.h>
#include <xdc/std.h>
#include <ti/sysbios/family/arm/m3/Hwi.h>
#include "inc/hw_memmap.h"
#include "inc/hw_ints.h"
#include "icall.h"
#include <board.h>
#include "hal_types.h"
#include <ti/sysbios/knl/Task.h>
#include <ti/sysbios/knl/Swi.h>
#include <ti/drivers/UART.h>
#include <ti/drivers/uart/UARTCC26XX.h>

#include "bas_niveau/uart.h"


// ****************************************************************************
// defines
// ****************************************************************************


// ****************************************************************************
// private prototypes
// ****************************************************************************

void uart_callback_rx(UART_Handle handle, void *data, size_t transferCount);
void uart_callback_tx(UART_Handle handle, void *data, size_t transferCount);


//*****************************************************************************
// globals
//*****************************************************************************


static UART_Handle uartHandle; // handle servant à manipuler le périphérique UART
static uint8_t rx_byte; // octet pour stocker les caractères reçus

//! \brief UART Object. Initialized in board specific files
extern UARTCC26XX_Object uartCC26XXObjects[];



//*****************************************************************************
// private functions
//*****************************************************************************

/*********************************************************************
 * @fn      cb_rx()
 * @brief   Callback appelé par le bas niveau lors de la réception d'un caractère
 * @param   handle: handle de l'UART,
 * @param   *data: pointeur vers les données reçues
 * @param   transferCount: nb d'octets reçus
 * @return  None
 */
void cb_rx(UART_Handle handle, void *data, size_t transferCount)
{
    ICall_CSState key;
    key = ICall_enterCriticalSection();

    UART_write(uartHandle, data, 1);

    UART_read(handle, data, 1);

    ICall_leaveCriticalSection(key);
}



//
/*********************************************************************
 * @fn      cb_tx()
 * @brief   Callback appelé par le bas niveau lors de la fin de l'envoi d'un caractère
 * @param   handle: handle de l'UART,
 * @param   *data: pointeur vers les données reçues
 * @param   transferCount: nb d'octets reçus
 * @return  None
 */
void cb_tx(UART_Handle handle, void *data, size_t transferCount)
{
    ICall_CSState key;
    key = ICall_enterCriticalSection();




    ICall_leaveCriticalSection(key);
}




//*****************************************************************************
// public functions
//*****************************************************************************



/*********************************************************************
 * @fn      uart_init()
 * @brief   Initialise l'UART du module BLE
 * @param   callbacks applicatifs TX et RX
 * @return  None
 */
void uart_init(void *callback_applicatif_tx_, void *callback_applicatif_rx_)
{
    UART_Params params;

    // Initialize the UART driver
    UART_init();

    // Configure UART parameters.
    UART_Params_init(&params);
    params.baudRate = 1200;
    params.readDataMode = UART_DATA_BINARY;
    params.writeDataMode = UART_DATA_BINARY;
    params.dataLength = UART_LEN_8;
    params.stopBits = UART_STOP_ONE;
    params.readMode = UART_MODE_CALLBACK;
    params.writeMode = UART_MODE_CALLBACK;
    params.readEcho = UART_ECHO_OFF;

    params.readCallback = cb_rx;
    params.writeCallback = cb_tx;

    // Open / power on the UART.
    uartHandle = UART_open(Board_UART0, &params);

    //Enable Partial Reads on all subsequent UART_read()
    UART_control(uartHandle, UARTCC26XX_CMD_RETURN_PARTIAL_ENABLE,  NULL);

    UART_read(uartHandle, &rx_byte, 1);
}

Everything works well until I pause and then restart the CC2640. Since this point, many bytes are missed

The issue is here even at a very low baudrate (1200 bds).

Here is the echoed back data :

1357
abcdefgh
1357
abcdefgh
1357
abcdefgh
1357
abcdefgh
1357
abcdefgh
1357

This issue does not appear if I send the 20 bytes every 1000 ms.

However it appears if data is sent every 400 ms.

Since 20 bytes @ 1200-8-N-1 needs 166 ms to be sent, normally there's plenty of free time and I don't understand why bytes are missed.

Thanks.