S140 RAM allocation running ble_app_uart example

[Roger]

Hi All,

I'm busy exploring the ble_peripheral_uart example and ran into a couple of issues I don't fully understand. Upon flashing the S140 SoftDevice and application program to the nRF52840, the following is observed:
1.) The advertising LED blinks and connects the peripheral to the app (master).
2.) It seems the program running on the nRF52840 hangs because UART Start! does not appear in the serial monitor.
3.) After a minute or so I get the following warnings and then the program crashes.

The values in the linker scripts are unchanged and shown below:

Under nRF5_SDK_14.0.0_3bcc1f7\components\toolchain\gcc the linker file memory is setup as:

FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x100000
RAM (rwx) :  ORIGIN = 0x20000000, LENGTH = 0x40000

Under nRF5_SDK_14.0.0_3bcc1f7\examples\ble_peripheral\ble_app_uart\pca10056\s140\armgcc the linker file memory is setup as:

FLASH (rx) : ORIGIN = 0x22000, LENGTH = 0xde000
RAM (rwx) :  ORIGIN = 0x20002a18, LENGTH = 0x3d5e8

After entering the proposed values in the linker script for the application, a fatal error is again displayed in RTT viewer after flashing and running the program. I'm thinking that this has something to with the RAM management of the S140 for this particular example?

This question has probably been asked many times but I couldn't find anything to help me out. Any suggestions will be greatly be appreciated. I'm using the nRF5_SDK_14.0.0_3bcc1f7 SDK which in turn uses the s140_nrf52840_5.0.0-2.alpha_softdevice to flash the SoftDevice.

Note: I have no issues running the ble_app_hrs example.

[Petter Myhre]

I don't understand. Does the unmodified example work? Why did you change the linker file? Did you make other changes?

[Roger]

Hi Petter,

The unmodified example works up to a point (starts advertising) and then a warning is given that the RAM should be adjusted after say a minute of advertising followed by a fatal error (see picture shown above).

The linker file is left unchanged. I used nRF5_SDK_14.0.0_3bcc1f7 SDK.

I ran the ble_app_uart example directly from the nRF5_SDK_14.0.0_3bcc1f7 folder with no changes.

[Petter Myhre]

Seems there is something funky going on with your UART.

The warnings and UART Start should be printed at once, but they are just warnings. They say that you have given the SoftDevice too much RAM, but that is not a problem.

You are also probably hitting the app_error_fault_handler() where Fatal is printed:

__WEAK void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info)
{
    NRF_LOG_ERROR("Fatal");
    ...

If you define DEBUG in your project you should hit app_error_handler() instead of app_error_handler_bare(), and you can get access to the file name, line number, telling you which function returned the error, and the error code returned of the function.

[Roger]

Thanks Petter, will look into it and let you know.