can I get the length of payload when using the funciton of nrf_gzll_fetch_packet_from_rx_fifo() in the gazell protocol on nrf51822

Question

Hi, 
 there is an example named gzll_ack_payload in the SDK of nrf51822.
when nrf51822 works in device mode, if a packet is send successfully, the funciton of nrf_gzll_device_tx_success() is called.
 my question: 
Can i get the length of payload while using nrf_gzll_fetch_packet_from_rx_fifo() if i don't know the length in advance? 
 thank you.

Håkon Alseth · Accepted Answer

Hi, 
 Yes, you can get the length.
The input in the nrf_gzll_fetch_packet_from_rx_fifo() is a uint32_t * length, so gazell will modify the input variable and return you the length of the received packet: 
 
uint8_t payload[NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH];
uint32_t length = NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH;
nrf_gzll_fetch_packet_from_rx_fifo(pipe, payload, &length);
/*
length will now hold the size of your received payload
*/

 
 Best regards
Håkon