how could i start ESB tx by using PPI + TIMER

[zyj]

hi:

   my chip is NRF52832 (512k FLASH + 64k RAM).

   I want to triggle ESB send process by PPI  + TIMER ,but i can't find the function like esb_task_address_get()，but i found some info in the datasheet:

 

so i write like this:

    ret_code_t err_code;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 1000);   
       

    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   false);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr =
        nrf_drv_timer_compare_event_address_get(&m_timer, NRF_TIMER_CC_CHANNEL0); 
//  uint32_t esb_send_task_addr   = nrf_esb_write_payload(&tx_payload);
    uint32_t esb_send_task_addr     = 0x40001000+0x008;

    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel,
                                          timer_compare_event_addr,    
                                          esb_send_task_addr);
    APP_ERROR_CHECK(err_code);

but its seems not work. I want to know if i get the wrong task_start address?or other problems may have.

Thank you !

[Håkon Alseth]

Hi,

 

PPI task and events can only be used on a peripheral level. nrf_esb is a higher level protocol, which sets up buffers and other protocol related logic, so PPI cannot be hooked up against the function to start the radio in a certain ESB mode.

You will have to involve the CPU in order to push a packet to the nrf_esb FIFO.

 

Kind regards,

Håkon

[zyj]

Thank you very much! i have solve the problems.