Softdevice assertion failed (PC=0x15124)

Question

Hello, 
 Our setup consists of two nrf52840 devices on custom boards. The devices establish a BLE connection via the Coded PHY (S=8). DLE is used. Connection event time is 7.5 ms and connection interval is also 7.5 ms. Slave latency is 0. On the connection there is almost no traffic but after some time the peripheral device is resetting itself after a failed softdevice assertion (id = 1; pc = 0x15412). The time until the assertion fails is varying between 10 minutes and several hours. 
 Further details: 
 
 Device: nrf52840 
 Setup: Custom board 
 Softdevice: S140 7.0.0 (s140_nrf52_7.0.0_softdevice.hex) 
 
 Thanks for your help in advance! 
 Best regards

F.S · Accepted Answer

Hi Simon, 
 Please excuse my delayed response. Thanks for the link with the overview of the memory region. It is very helpful! I check the memory regions based on the overview and within our application everything should be in range. 
 In the mean time I was able to solve the problem. The connection stays now active over several days without a device reset. The step to solve the problem was to reduce the LL payload size back to fixed 27 bytes. Previously after a connection setup a payload size of 251 bytes was requested. Later I found in the release note of SoftDevice 7.0.0 a limitation which mentions that the LL payload size is limited to 27 bytes for connection via Coded PHY. Maybe the violation of this limitation within our application caused the assertion and the device reset? 
 Thanks for your help and your ideas solving this issue! 
 Best regards, 
 Florian

Softdevice assertion failed (PC=0x15124)

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