ARM MDK Getting Started Guide

This tutorial will go over integrating the panics component of the Memfault Firmware SDK into a system using ARM Compiler 5 and the MDK Microcontroller Development Kit.

Clone Memfault SDK

Using a Git client, clone the memfault-firmware-sdk repository from:

$ git clone https://github.com/memfault/memfault-firmware-sdk.git

Add required Memfault SDK include paths to target

Add required Memfault SDK sources to target

Add the sources at $MEMFAULT_FIRMWARE_SDK/components/[panics, core, util]/src to your project. For the panics component, you do not need to add memfault_fault_handling_xtensa.c. The directories included should look something like:

Make sure Memfault SDK sources are being compiled in C99 mode

Implement platform specific storage region for crash data

We typically recommend starting with the RAM based Coredump port. By default this will only save the top of the stack at the time of crash but it lets you quickly get the system up and running and get a feel for how things work. To do this:

1. Add ports/panics/src/memfault_platform_ram_backed_coredump.c to the build

2. Mark the section being used a a UNINIT region in the scatter file for the target. This will look something like:

   NOINIT_IRAM1 0x20010000 UNINIT 0x00000200  { ;no init section
        *(.noinit*)
      }

Coredump data can also be stored to any other backing storage (eMMc, external NOR flash, internal flash, etc) by implementing the required dependencies.

Implement other platform dependencies

In order to save coredumps, you will need to fill in the functions in the block below

#include "memfault/panics/assert.h"
#include "memfault/core/platform/core.h"
#include "memfault/core/platform/debug_log.h"
#include "memfault/core/platform/device_info.h"

void memfault_platform_log(eMemfaultPlatformLogLevel level, const char *fmt, ...) {
  // Hook up logging implementation
}

void memfault_platform_get_device_info(sMemfaultDeviceInfo *info) {
  // platform specific version information
  *info = (sMemfaultDeviceInfo) {
    .device_serial = "DEMOSERIAL",
    .software_type = "nrf-main",
    .software_version = "1.0.0",
    .hardware_version = "nrf-proto",
  };
}

void memfault_platform_reboot(void) {
  // Last function called before memfault after a crash
  // expect the platform to reboot the system
  __breakpoint(0x1);
}

Publish data to the Memfault cloud

Extensive details about how data from the Memfault SDK makes it to the cloud can be found here. In short, all data is published via the same "chunk" REST endpoint.

#include "memfault/core/data_packetizer.h"
// [...]

bool try_send_memfault_data(void) {
  // buffer to copy chunk data into
  uint8_t buf[USER_CHUNK_SIZE];
  size_t buf_len = sizeof(buf);

  bool data_available = memfault_packetizer_get_chunk(buf, &buf_len);
  if (!data_available ) {
    return false; // no more data to send
  }

  // send payload collected to chunks/ endpoint
  user_transport_send_chunk_data(buf, buf_len);
  return true;
}

void send_memfault_data(void) {
  // [... user specific logic deciding when & how much data to send
  while (try_send_memfault_data()) { }
}

Server-side rate limiting will apply to the device you're using to work on the integration process. Once you can see the device on the Memfault Web App, consider enabling Server-Side Developer Mode for it on the Memfault Web App to temporarily bypass these limits.