timer is not woring

Question

hi........ 
 i am using nrf52382 , merged the uart , timer and twi . while debugging i am getting the error unknown function 0x000008C8 
 . */
int main(void)
{
bool erase_bonds;



 // Initialize.
 uart_init();
 log_init();
 timers_init();
 buttons_leds_init(&erase_bonds);
 power_management_init();
 ble_stack_init();
 gap_params_init();
 gatt_init();
 services_init();
 advertising_init();
 conn_params_init();

 printf("
UART started.
");
 NRF_LOG_INFO("Debug logging for UART over RTT started.");
 advertising_start();


 

twi_init();
 LM75B_set_mode();
 

uint32_t time_ms = 50000; //Time(in miliseconds) between consecutive compare events.
 uint32_t time_ticks;
 uint32_t err_code = NRF_SUCCESS;

 
 

 //Configure all leds on board.
 bsp_board_init(BSP_INIT_LEDS);

 //Configure TIMER_LED for generating simple light effect - leds on board will invert his state one after the other.
 nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
 err_code = nrf_drv_timer_init(&TIMER_SENSOR, &timer_cfg, timer_sensor_event_handler);
 APP_ERROR_CHECK(err_code);

 nrf_drv_timer_extended_compare(
 &TIMER_SENSOR, NRF_TIMER_CC_CHANNEL0, time_ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);


 time_ticks = nrf_drv_timer_ms_to_ticks(&TIMER_SENSOR, time_ms);

 NRF_LOG_INFO("SUCCESS1"); 




 

 // Start execution.
 
 while (true)
 {
 nrf_delay_ms(6000);

 while (m_xfer_done == false);

 m_xfer_done = false;
 
 uint8_t reg[2] = {0x00U};
 err_code = nrf_drv_twi_tx(&m_twi,LM75B_ADDR, reg, sizeof(reg), true);
 APP_ERROR_CHECK(err_code);
 while (m_xfer_done == false);
 nrf_delay_ms(5);
 
 m_xfer_done = false;
 ret_code_t err_code1 = nrf_drv_twi_rx(&m_twi,LM75B_ADDR, &m_sample, sizeof(m_sample));
 APP_ERROR_CHECK(err_code1);
 NRF_LOG_INFO("%d", m_sample);

}
 
 
 }