ShockBurst Payload size

[NewtoM]

Hi,

I am trying to use enhanced shockburst (ESB) to stream data at high bitrate between two nRF52 development boards. Even though I set the protocol to 2Mbs, the max netto bitrate I get is barely above 400kbs, which may be due to my current payload size of 25 bytes per packet.

So I would like to increase the payload size, but I am somewhat confused at this point, because I feel that different documents deliver contradictory information.

First off, the SDK examples on ESB use small payload sizes.

The infocenter says that "1 to 252 bytes static payload length between nRF5 Series devices" is featured. Static payload length would be fine with me.

However, the nrf_esb_payload_t type definition clearly only allocates 32 bytes for the payload.

So, what is the truth, and how do I use e.g. 252 byte-long payloads with ESB?

Thank you in advance! Tamas

[djqtsg]

check this out

link text

[NewtoM]

Hi djqtsg, thanks for the answer. The link seems promising. However, independently of using or not using th NRF_ESB_CREATE_PAYLOAD macro, I still don't see how the nrf_esb_payload_t struct may hold more than 32 bytes of payload data, if it is defined as it is in the v11 SDK. Or may I simply alter this number in the Nordic source code?

[djqtsg]

yes, you got to change 32 bytes to whatever you want, but <= 252. Read that post carefully since you may need to change a few places in order to make it work.

[NewtoM]

I will give it a try. Thank you!

[SL06]

I know that this post is old but I was looking for the answer for several days and decide to  share what I have found for the next user in need. I am not a programmer, so be careful with this.  In SDK14 esb tx , rx exemples, I have  nrf24_esb.h file to :  

// Hardcoded parameters - change if necessary
#ifndef NRF_ESB_MAX_PAYLOAD_LENGTH
#define     NRF_ESB_MAX_PAYLOAD_LENGTH          252                  //!< The maximum size of the payload. Valid values are 1 to 252.
#endif

I have also increase the rx, tx fifo buffer size from 8 to 32. I hope this is a good idea, I am not shure.

#define     NRF_ESB_TX_FIFO_SIZE                32                  //!< The size of the transmission first
#define     NRF_ESB_RX_FIFO_SIZE                32  

These changes will affect all programs that use the nrh_esb.h file.   There could be another way to do this.


Inside main.c  tx and Rx example I have change that line:

 nrf_esb_config.payload_length           = 252;//SL  max lenght for nrf52  is 255

.....

main.c TX side :  

char mystring[] = "xyz:1.23,1.34.1.65.0.23 a,b,c,d,e,f,g,h,i,j,k, etc...";   
    


    tx_payload.pipe = 3;     //  the pipe adress  used for transmitting 
    tx_payload.length =  strlen(mystring) +1;  //payload lenght+1

for (uint8_t i = 0; i < tx_payload.length; i++) {
			tx_payload.data[i] = mystring[i];
		        }

the packet  is ready o be sent.

main.c RX side (with nrf_log enable in sdk_config) 

case NRF_ESB_EVENT_RX_RECEIVED:
            NRF_LOG_DEBUG("RX RECEIVED EVENT");

               NRF_LOG_DEBUG("Print payload pipe %i \r", rx_payload.pipe);
               NRF_LOG_DEBUG("Print payload lenght %i \r",rx_payload.length);
               NRF_LOG_INFO("%s",  rx_payload.data);  // will print the string.

I hope that this post will be helpful and other will build on it.