Flash read error 16 [NRF_ERROR_INVALID_ADDR] when code executing outside of debugger

[NickH]

When I run my code using Segger debugger, all is well and I can read and write from flash with issues.  However, when I run the same code independently I sometimes get:

ASSERT ERROR 16 [NRF_ERROR_INVALID_ADDR]

when calling:

#define FLASH_START_ADDRESS 0x7e000

#define FLASH_END_ADDRESS   0x7ffff

…

ret = nrf_fstorage_read(&fstorage, FLASH_START_ADDRESS, buf, size);

APP_ERROR_CHECK(ret);

at this point buf is 1940 bytes.

The application RAM start is 0x200039d8 as determined by nrf_sdh_ble_enable().

My set-up is:

Module: nrf52840

Hardware: nrf52840 DVK and custom board

Soft Device: s140_nrf52_7.2.0_softdevice

SDK: nRF5_SDK_17.0.2_d674dde

Memory Segments:

FLASH RX 0x0 0x100000;RAM1 RWX 0x20000000 0x40000

Section Placement Macros:

FLASH_PH_START=0x0

FLASH_PH_SIZE=0x100000

RAM_PH_START=0x20000000

RAM_PH_SIZE=0x40000

FLASH_START=0x27000

FLASH_SIZE=0x2a222

RAM_START=0x200039d8

RAM_SIZE=0x3dda0

Stack and Heap both set to:

32768 bytes

I did notice that when code downloaded via Segger and then viewed via nRF Connect programmer, there is a memory chunk starting at 0x7000 and ending 0x7e676.  [I don’t know why this is not either the size of my file ie 1940 bytes or the 0x7ffff specified as flash end address.]

I also don’t get this memory chunk when the code is run after being downloaded via nrfjprog or nRF Connect programmer but either way, I still get the invalid address error.

I’m clearly misunderstanding something here and would be grateful for some pointers….

Nick

[NickH]

I have tried some further debug.  I changed the sample project to use the fds API's rather than writing directly to flash as per the 'flash_fds' example.

I have noticed the following:

 - the code will run on the custom board after being downloaded via debugger using SWD pins

 - after running OK in debug mode, code also runs OK and flash accessed correctly even after a board reset

 - however, if power is cycled to the custom board, code then runs until any kind of flash access attempted wherein a invalid address message is seen

- if code is downloaded via nrfprog (after chip erase), code only runs after power to chip cycled. 

 Q - what is different between a reset and a power cycle in terms of flash?

This flash behaviour is NOT seen on DK when 52840 run isolated from rest of DVK so it must be something different on the custom board...

[Jørgen Holmefjord]

NickH said:

Q - what is different between a reset and a power cycle in terms of flash?

I can't think of any particular difference between these two operations.

NickH said:

- if code is downloaded via nrfprog (after chip erase), code only runs after power to chip cycled. 

Do the code not run if you reset the board from nrfjprog?:

nrfjprog -r