fds_record_find function causes crash

[sean]

hi，

  I'm working on passthrough firmware(nRF5_SDK_17.1.0_ddde560)，I need to increase the priority of the serial port,see following code,When APP_UART_FIFO_INIT priority set to APP_IRQ_PRIORITY_HIGHEST,the fds_record_update it causes a crash, and it doesn't have any logs output,Debug locate to nrf_fstorage.c at line 169(return (p_fs->p_api)->write(p_fs, dest, p_src, len, p_context);)。then APP_UART_FIFO_INIT set APP_IRQ_PRIORITY_LOWEST/APP_IRQ_PRIORITY_THREAD working properly.

[Turbo J]

Won't work.

The fstroage has to call softdevice for the write, which you cannot do from APP_IRQ_PRIORITY_HIGHEST context.

I recommend using a FIFO for UART data and to do the actual writing in the main loop.

Edit: Calling Softtdevice from a high priority handler should cause a Hard Fault according to the ARM ARM.

[sean]

hi，

  I had using FIFO for UART ,and APP_UART_DATA_READY event only put data to buf，when high passthrough（10KB/S） data to ble,uart rx will lost lot of data ,only to improve APP_UART_FIFO_INIT priority to solve the packet loss problem。

[Turbo J]

A 10KB/s throughput requires UART hardware handshake lines (RTS/CTS) to be reliable on NRF52x.

Look at how long a flash page write and especially erase cycle lasts and how little time you have per UART byte.

[sean]

hi，

 Pass-through and flash writing（or erase） are mutex，Do not write flash when passing through data