failed to write on ble lbs in central

[sowmiya]

hai ,

           i am using nrf52840 sdk 15.2 and  in my application  i have to connect nrf52840 central to peripheral after connection i have write data on ble_lbs_led_status_send  i can able to write from central to peripheral and also getting response but some of the time its connecting but suddenly gets disconnecting before writing , it is not getting inside thelbs_c_evt_handler disconnecting within a second .i need to write data without frequent failures .any idea on this could you please explain on this

Thanks,

sowmiya

[Kenneth]

You should add debugging on the peripheral and central, are both peers experiencing a disconnect or is possible one peer doing a reset. A reset may for instance be caused by an assert, since the fault handler is by default setup to do a reset on assert to recover.

Best regards,
Kenneth

[sowmiya]

thank you for your quick reply 

I have debugged on both central and peripheral  its not getting reset , dont know why its disconnecting frequently 

[Kenneth]

What LFCLK source (32kHz) are you using, and what tolerance (in ppm) have you configured when enabling the softdevice?

What is the disconnect reason when receiving the disconnect event?

Best regards,
Kenneth

[sowmiya]

NRF_CLOCK_LF_ACCURACY_20_PPM

 i have noted that the disconnection p_gap_evt->params.disconnected. reason is 62 (disconnected reson is  0x3e), i m looking whats the reason 

thanks.

sowmiya

[Kenneth]

Hi,

BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED is something you can get shortly after the central tries to establish a connection. This means that the central have sent the connection request packet, but due to noise in environment, the packet was lost, and no link was established. In such case the central should try to re-connect again, and re-send data.

Best regards,
Kenneth

[sowmiya]

yes, tried to reconnect and sending data after 2 to 3 retires getting success  and when central to peripheral distance at 5 meters sometimes getting failed when i retried also. on peripheral side gap connection interval is

#define MIN_CONN_INTERVAL MSEC_TO_UNITS(100, UNIT_1_25_MS) /**< Minimum acceptable connection interval (0.5 seconds). */
#define MAX_CONN_INTERVAL MSEC_TO_UNITS(200, UNIT_1_25_MS) /**< Maximum acceptable connection interval (1 second). */
#define SLAVE_LATENCY 3 /**< Slave latency. */
#define CONN_SUP_TIMEOUT MSEC_TO_UNITS(4000, UNIT_10_MS)  

[Kenneth]

Have you tuned and verified output power and antenna matching on your hardware? This is something we can help you with, but first we need to review your schematic and layout. You can create a private case to upload your schematic and layout for feedback.

Best regards,
Kenneth